®
Intel 82854 Graphics Memory
Controller Hub (GMCH)
Datasheet
Revision 2.0
June 2005
Order Number: D15343-003
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Contents
Contents
1.0 Introduction....................................................................................................................................11
Overview.............................................................................................................................11
Terminology........................................................................................................................17
Reference Documents........................................................................................................19
®
2.0 Intel 82854 GMCH Overview.......................................................................................................21
System Architecture............................................................................................................21
2.1.1 Intel 82854 GMCH...............................................................................................21
®
GMCH System Memory Interface.......................................................................................22
Graphics Features ..............................................................................................................23
Display Features.................................................................................................................23
2.5.1 GMCH Analog Display Port ...................................................................................23
2.5.2 GMCH Integrated DVO Ports ................................................................................23
Hub Interface ......................................................................................................................24
Address Decode Policies....................................................................................................24
GMCH Clocking..................................................................................................................25
System Interrupts................................................................................................................26
3.0 Signal Description..........................................................................................................................27
Host Interface Signals.........................................................................................................28
DDR SDRAM Interface.......................................................................................................31
Hub Interface Signals .........................................................................................................32
Clocks.................................................................................................................................33
Internal Graphics Display Signals.......................................................................................35
3.5.1 Digital Video Output B (DVOB) Port ......................................................................35
3.5.2 Digital Video Output C (DVOC) Port......................................................................36
3.5.3 Analog CRT Display ..............................................................................................37
3.5.4 General Purpose Input/Output Signals ..................................................................38
Voltage References, PLL Power.........................................................................................39
4.0 Register Description ......................................................................................................................41
Conceptual Overview of the Platform Configuration Structure ...........................................41
Nomenclature for Access Attributes ...................................................................................42
Standard PCI Bus Configuration Mechanism .....................................................................43
Routing Configuration Accesses.........................................................................................43
4.4.1 PCI Bus #0 Configuration Mechanism...................................................................43
Register Definitions.............................................................................................................44
I/O Mapped Registers.........................................................................................................45
4.6.2 CONFIG_DATA – Configuration Data Register.....................................................47
VGA I/O Mapped Registers ................................................................................................48
4.8.1 VID – Vendor Identification Register......................................................................51
4.8.2 DID – Device Identification Register ......................................................................51
4.8.3 PCICMD – PCI Command Register.......................................................................52
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4.8.4 PCI Status Register ...............................................................................................53
4.8.5 RID – Register Identification..................................................................................54
4.8.6 SUBC – Sub Class Code Register ........................................................................54
4.8.7 BCC – Base Class Code Register.........................................................................55
4.8.8 HDR – Header Type Register................................................................................55
4.8.9 SVID – Subsystem Vendor Identification Register ................................................55
4.8.10 SID – Subsystem Identification Register ...............................................................56
4.8.11 CAPPTR – Capabilities Pointer Register...............................................................56
4.8.12 CAPID – Capabilities Identification Register (Device #0) ......................................57
4.8.20 ERRSTS – Error Status Register (Device #0) .......................................................66
4.8.21 ERRCMD – Error Command Register (Device #0)................................................67
4.9
Intel 854 GMCH Main Memory Control, Memory I/O Control Registers (Device #0, Function
4.9.1 VID – Vendor Identification Register......................................................................73
4.9.2 DID – Device Identification Register......................................................................73
4.9.3 PCICMD – PCI Command Register.......................................................................74
4.9.4 PCISTS – PCI Status Register ..............................................................................75
4.9.5 RID – Revision Identification Register ...................................................................76
4.9.6 RID – Revision Identification Register ...................................................................76
4.9.7 BCC – Base Class Code Register.........................................................................76
4.9.8 HDR – Header Type Register................................................................................77
4.9.9 SVID – Subsystem Vendor Identification Register ................................................77
4.9.10 SID – Subsystem Identification Register ...............................................................77
4.9.11 CAPPTR – Capabilities Pointer Register...............................................................78
4.9.13 DRA – DRAM Row Attribute Register (Device #0) ................................................79
4.9.14 DRT – DRAM Timing Register (Device #0) ...........................................................80
4.9.16 DRC – DRAM Controller Mode Register (Device #0)............................................85
4.9.17 DTC – DRAM Throttling Control Register (Device #0) ..........................................88
4.10 Intel 854 GMCH Configuration Process Registers (Device #0, Function #3) .....................92
4.10.1 VID – Vendor Identification Register......................................................................92
4.10.2 DID – Device Identification Register......................................................................93
4.10.3 PCICMD – PCI Command Register.......................................................................94
4.10.4 PCISTS – PCI Status Register ..............................................................................95
4.10.5 RID – Revision Identification Register ...................................................................96
4.10.6 SUBC – Sub-Class Code Register ........................................................................96
4.10.7 BCC – Base Class Code Register.........................................................................96
4.10.8 HDR – Header Type Register................................................................................97
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4.10.9 SVID – Subsystem Vendor Identification Register.................................................97
4.10.10 ID – Subsystem Identification Register..................................................................97
4.10.11 CAPPTR – Capabilities Pointer Register...............................................................98
4.10.12 HPLLCC – HPLL Clock Control Register (Device #0) ...........................................98
®
4.11.1 VID – Vendor Identification Register (Device #2) ................................................101
4.11.2 DID – Device Identification Register (Device #2).................................................101
4.11.3 PCICMD – PCI Command Register (Device #2) .................................................102
4.11.4 PCISTS – PCI Status Register (Device #2).........................................................103
4.11.5 RID – Revision Identification Register (Device #2)..............................................103
4.11.6 CC – Class Code Register (Device #2) ...............................................................104
4.11.7 CLS – Cache Line Size Register (Device #2)......................................................104
4.11.8 MLT – Master Latency Timer Register (Device #2) .............................................104
4.11.9 HDR – Header Type Register (Device #2)...........................................................105
4.11.12 IOBAR – I/O Base Address Register (Device #2)................................................106
4.11.14 SID – Subsystem Identification Register (Device #2) ..........................................107
4.11.17 INTRPIN – Interrupt Pin Register (Device #2) .....................................................108
4.11.18 MINGNT – Minimum Grant Register (Device #2) ................................................108
4.11.19 MAXLAT – Maximum Latency Register (Device #2)............................................109
®
5.0 Intel 82854 GMCH System Address Map..................................................................................111
System Memory Address Ranges ....................................................................................111
DOS Compatibility Area....................................................................................................112
Extended System Memory Area.......................................................................................114
5.4.1 15 MB-16 MB Window.........................................................................................115
5.4.2 Pre-allocated System Memory.............................................................................115
5.4.4 System Memory Shadowing ................................................................................119
5.4.5 I/O Address Space...............................................................................................119
5.4.7 Hub Interface Decode Rules................................................................................121
6.0 Functional Description.................................................................................................................123
Host Interface Overview ...................................................................................................123
Dynamic Bus Inversion.....................................................................................................123
6.2.1 System Bus Interrupt Delivery .............................................................................123
6.2.2 Upstream Interrupt Messages .............................................................................124
System Memory Interface.................................................................................................124
6.3.1 DDR SDRAM Interface Overview ........................................................................124
6.3.2 System Memory Organization and Configuration ................................................124
6.3.3 DDR SDRAM Performance Description...............................................................125
Integrated Graphics Overview ..........................................................................................126
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6.4.1 3D/2D Instruction Processing ..............................................................................126
6.4.2 3D Engine............................................................................................................127
6.4.3 Raster Engine......................................................................................................130
6.4.4 2D Engine............................................................................................................133
6.4.5 Planes and Engines.............................................................................................134
6.4.6 Hardware Cursor Plane (Native Graphic Mode only) ..........................................134
6.4.7 Overlay Plane ......................................................................................................135
6.4.8 Video Functionality ..............................................................................................137
Internal Graphic Display Interface ....................................................................................138
6.5.1 Pipe A Timing Generator Unit..............................................................................138
6.5.2 Blend Function.....................................................................................................141
6.5.3 Interlaced Video Field display..............................................................................141
6.5.4 Interlace support for Video Overlay Window .......................................................143
6.5.5 Analog Display Port Characteristics ....................................................................145
7.0 Power and Thermal Management ...............................................................................................147
General Description of Supported CPU States.................................................................148
General Description of ACPI States .................................................................................148
Internal Thermal Sensor ...................................................................................................149
7.3.1 Overview..............................................................................................................149
7.3.2 Hysteresis Operation ...........................................................................................149
External Thermal Sensor Input.........................................................................................150
7.4.1 Usage ..................................................................................................................150
®
8.0 Intel 82854 GMCH Strap Pins...................................................................................................151
8.1 Strapping Configuration....................................................................................................151
9.0 Ballout and Package Information.................................................................................................153
VCC/VSS Voltage Groups................................................................................................154
Package Mechanical Information......................................................................................164
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Contents
Figures
Intel® 854 Chipset system block diagram (Native Graphic mode) .............................................16
Configuration Address Register..................................................................................................45
Configuration Data Register .......................................................................................................47
PAM Registers............................................................................................................................62
Simplified View of System Address Map ..................................................................................111
Detailed View of System Address Map.....................................................................................112
ARIB TR-B15 Plane Resolutions..............................................................................................139
H, V Parameters .......................................................................................................................140
®
11 Timing Register Switching ........................................................................................................144
®
12 Intel 82854 GMCH Ballout Diagram (Top View).....................................................................153
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13 Intel 82854 GMCH Micro-FCBGA Package Dimensions (Top View) .....................................164
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14 Intel 82854 GMCH Micro-FCBGA Package Dimensions (Side View) ....................................165
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15 Intel 82854 GMCH Micro-FCBGA Package Dimensions (Bottom View) ................................166
Tables
Terms and Descriptions..............................................................................................................17
Reference Documents................................................................................................................19
DDR SDRAM Memory Capacity.................................................................................................22
Intel 82854 GMCH Interface Clocks.........................................................................................25
Host Interface Signal Descriptions..............................................................................................28
DDR SDRAM Interface Descriptions .........................................................................................31
Hub Interface Signals ................................................................................................................32
Clock Signals..............................................................................................................................33
Digital Video Output B (DVOB) Port Signal Descriptions ...........................................................35
®
10 Digital Video Output C (DVOC) Port Signal Descriptions...........................................................36
11 DVOB and DVOC Port Common Signal Descriptions ...............................................................37
12 Analog CRT Display Signal Descriptions....................................................................................37
13 GPIO Signal Descriptions...........................................................................................................38
14 Voltage References, PLL Power ................................................................................................39
15 Device Number Assignment .......................................................................................................41
16 Nomenclature for Access Attributes ...........................................................................................42
17 VGA I/O Mapped Register List ...................................................................................................48
18 Index – Data Registers ...............................................................................................................48
19 GMCH Configuration Space - Device #0, Function#0 ................................................................49
20 Attribute Bit Assignment .............................................................................................................61
21 PAM Registers and Associated System Memory Segments......................................................63
23 Configuration Process Configuration Space (Device#0, Function #3)........................................92
®
25 Integrated Graphics Device Configuration Space (Device #2, Function#0) ............................100
26 System Memory Segments and Their Attributes ......................................................................113
27 Table 33. Pre-allocated System Memory..................................................................................115
28 SMM Space Transaction Handling ...........................................................................................119
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Intel 82854 Graphics Memory Controller Hub (GMCH)
29 Relation of DBI Bits to Data Bits...............................................................................................123
30 Data Bytes on DDR DIMM Used for Programming DRAM Registers.......................................125
31 Dual Display Usage Model (Native Graphic Mode only) ..........................................................134
32 DVO Control Data Bits..............................................................................................................143
33 Strapping Signals and Configuration........................................................................................151
®
34 Intel 82854 GMCH Straps for Frequency/CPU Configuration ................................................152
35 Voltage Levels and Ball Out for Voltage Groups......................................................................154
36 Ballout Table ............................................................................................................................155
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Contents
Revision History
Date
Revision
Description
Initial release of this document.
March 2005
1.0
2.0
Add support for Genuine Intel® Processor at 1.2 GHz and
Genuine Intel® Processor at 1.5 GHz technology.
June 2005
§ §
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Intel 82854 Graphics Memory Controller Hub (GMCH)
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Introduction
1.0
Introduction
®
This document is the datasheet for the Intel 82854 Graphics Memory Controller Hub (GMCH).
1.1
Overview
®
®
The Intel 854 chipset is a combination of the Intel 82854 Graphics Memory Controller Hub
(GMCH) (Graphics Memory Controller Hub) and ICH4-M (I/O Controller Hub). The Intel 854
®
®
Chipset is designed to work with the Ultra Low Voltage (ULV) Intel Celeron M processor at 600
MHz with 512 KB of on-die L2 cache on an 0.13 micron process, Genuine Intel Processor at 1.2
GHz, and Genuine Intel Processor at 1.5 GHz. The Intel 82854 GMCH provides high-
854 chipset block diagram.
®
®
®
Processor/Host Bus Support
®
®
The Genuine Intel Processor at 1.2 GHz and Genuine Intel Processor at 1.5 GHz have the
following key features:
• High performance, low power core
• AGTL+ bus driver technology with integrated AGTL+ termination resistors and low voltage
operation
• Supports Intel Architecture with Dynamic Execution
• 400-MHz, Source-Synchronous processor system bus
• 2x address, 4x data
• On-die, primary 32-Kbyte instruction cache and 32-Kbyte write-back data cache
• On-die, 512-Kbyte second level cache with Advanced Transfer Cache Architecture
• Advanced Branch Prediction and Data Prefetch Logic
• Streaming SIMD Extensions 2 (SSE2)
• Advanced Power Management features
Memory System
• Directly supports one DDR SDRAM channel, 64-bits wide
• Supports 266/333-MHz DDR SDRAM devices with max of two, double-sided DIMM (four
rows populated) with unbuffered PC2100/PC2700 DDR SDRAM.
• Supports 128-Mbit, 256-Mbit, and 512-Mbit technologies providing maximum capacity of
2 GB with x16 devices
• All supported devices have four banks
• Supports up to 16 simultaneous open pages
• Supports page sizes of 2 kB, 4 kB, 8 kB, and 16 kB. Page size is individually selected for
every row
• UMA support only
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Intel 82854 Graphics Memory Controller Hub (GMCH)
System Interrupts
• Supports Intel 8259 and front side bus interrupt delivery mechanism
• Supports interrupts signaled as upstream memory writes from PCI and Hub interface
• MSI sent to the CPU through the system bus
• IOxAPIC in ICH4-M provides redirection for upstream interrupts to the system bus
Video Stream Decoder
• Hardware motion compensation for MPEG2
• All video format decoder (18 ATSC video formats) supported
• Dynamic Bob and Weave support for video streams
• Software DVD at 60 Fields/second and 30 frames/second full screen
• Support for standard definition DVD (i.e., NTSC pixel resolution of 720x480, and so on)
quality encoding at low CPU utilization
Video Overlay
• Single high quality scalable overlay and second Sprite to support second overlay
• Multiple overlay functionality provided via arithmetic stretch BLT (Block Transfer)
• 5-tap horizontal, 3-tap vertical filtered scaling
• Multiple overlay formats
• Direct YUV from overlay to TV-out
• Independent gamma correction
• Independent brightness / contrast/ saturation
• Independent tint/hue support
• Destination colorkeying
• Source chromakeying
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Introduction
Display
• Analog display support
— 350-MHz integrated 24-bit RAMDAC that can drive a standard progressive scan analog
monitor with pixel resolution up to 1600x1200 at 85 Hz and up to 2048x1536 at 75 Hz
• Dual independent pipe support
— Concurrent: different images and display timings on each display device
— Simultaneous: same images and display timings on each display device
• DVO (DVOB and DVOC) support
— Digital video out ports DVOB and DVOC with 165-MHz dot clock on each 12-bit
interface; two 12-bit channels can be combined to form one dual channel 24-bit interface
with an effective dot clock of 330 MHz
— The combined DVO B/C ports as well as individual DVO B/C ports can drive a variety of
DVO devices (TV-Out Encoders, TMDS and LVDS transmitters, and so on) with pixel
resolution up to 1600x1200 at 85 Hz and up to 2048x1536 at 72 Hz.
— Compliant with DVI Specification 1.0
• Tri-view support through DVO B, C port, and CRT
Internal Graphics Features
• Up to 64 MB of dynamic video memory allocation
• Display image rotation
• Graphics core frequency at 200, 250 MHz
• 2D graphics engine
— Optimized 128-bit BLT engine
— Ten programmable and predefined monochrome patterns
— Alpha Stretch BLT (via 3D pipeline)
— Anti-aliased lines
— Hardware-based BLT Clipping and Scissoring
— 32-bit Alpha Blended cursor
— Programmable 64 x 64 3-color Transparent cursor
— Color Space Conversion
— Three Operand Raster BLTs
— 8-bit, 16-bit, and 32-bit color
— ROP support
— DIB translation and Linear/Tile addressing
— Multiple hardware color cursor support (32-bit with alpha and legacy 2-bpp mode)
2
— Accompanying I C and DDC channels provided through multiplexed interface
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Intel 82854 Graphics Memory Controller Hub (GMCH)
•
3D graphics engine
— 3D setup and render engine
— Enhanced Hardware Binning Instruction Set supported
— Zone rendering
— High quality performance texture engine
— Viewpoint transform and perspective divide
— Triangle lists, strips and fans support
— Indexed vertex and flexible vertex formats
— Pixel accurate fast scissoring and clipping operation
— Backface culling support
— Direct 3D support
— Anti-Aliased lines support
— Sprite points support
— Provides the highest sustained fill rate performance in 32-bit color and 24-bit W mode
— High quality performance texture engine
— 266-MegaTexel/s peak performance
— Per pixel perspective corrected texture mapping
— Single pass texture compositing (multi-textures)
— Enhanced texture blending functions
— Twelve level of detail MIP map sizes from 1x1 to 2k x 2k
— Numerous texture formats
— Alpha and Luminance maps
— Texture chromakeying
— Bilinear, trilinear, and anisotropic MIP map filtering
— Cubic environment reflection mapping
— Dot product bump-mapping
— Embossed bump-mapping
— DXTn texture decompression
— FX1 texture compression
— 3D graphics rasterization enhancements
— One Pixel per clock
— Flat and Gouraud shading
— Color alpha blending for transparency
— Vertex and programmable pixel fog and atmospheric effects
— Color specular lighting
— Z Bias support
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Introduction
— Dithering
— Line and full-scene anti-aliasing
— 16- and 24-bit Z buffering
— 16- and 24-bit W buffering
— 8-bit Stencil buffering
— Double and triple render buffer support
— 16- and 32-bit color
— Destination alpha
— Vertex cache
— Optimal 3D resolution supported
— Fast Clear support
— ROP support
Hub Interface to ICH4-M
• 266-MB/s point-to-point Hub interface to ICH4-M
• 66-MHz base clock
Graphic Power Management
• Dynamic Frequency Switching
• Memory Self-Refresh during C3
• Intel Display Power Saving Technology
Power Management
• SMRAM space remapping to A0000h (128-kB)
• Supports extended SMRAM space above 256-MB, additional 1-MB TSEG from top of
memory, cacheable (cacheability controlled by CPU)
• APM Rev 1.2 compliant power management
• Supports Suspend to System Memory (S3), Suspend to Disk (S4) and Soft Off (S5)
• ACPI 1.0b, 2.0 support
• Optimized Clock Gating for 3D and Display Engines
• On-Die Thermal Sensor
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Intel 82854 Graphics Memory Controller Hub (GMCH)
Package
732-pin Micro-FCBGA (37.5 x 37.5 mm)
Figure 1.
Intel® 854 Chipset system block diagram (Native Graphic mode)
®
®
Intel Celeron M
Processor
VGA
400 MHz
512 MB DDR
Memory Down
VGA
DVO
Intel® 82854
333 MHz
(GMCH)
TV
ADD Slot
IDE
USB 2.0/1.1
LCI
®
Intel 82801DBM
AC Link
Audio
Codec
(ICH4-M)
6 USB
LAN
PHY
LPC
FWH
PS/2
PCI Slots
SIO
Serial
16
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Introduction
1.2
Terminology
Table 1.
Terms and Descriptions
Term
Description
AGTL+
BLI
Advanced Gunning Transceiver Logic + (AGTL+) bus
Backlight Inverter
Core
CPU
CRT
DBI
The internal base logic in the Intel® 82854 GMCH
Central Processing Unit
Cathode Ray Tube
Dynamic Bus inversion
DBL
Display Brightness Link
DDC
DPMS
DVI*
Display Data Channel (standard created by VESA)
Display Power Management Signaling (standard created by VESA)
Digital Visual Interface is the interface specified by the DDWG (Digital Display
Working Group) DVI Spec. Rev. 1.0 utilizing only the Silicon Image developed
TMDS protocol
DVMT
DVO
EDID
EIST
FSB
Dynamic Video Memory Technology
Digital Video Out
Extended Display Identification Data
Enhanced Intel® SpeedStep® Technology
Front side bus. Connection between Intel® 82854 GMCH and the CPU. Also
known as the Host interface
Full Reset
GMCH
HD
A full Intel® 82854 GMCH Reset is defined in this document when RSTIN# is
asserted
Refers to the GMCH component. Throughout this datasheet, the Intel® 82854
Graphics Memory Controller Hub (GMCH) will be referred to as the GMCH.
High definition, typically MP@HL for MPEG2; Resolution supported are 720p,
1080i and 1080p
Host
This term is used synonymously with processor
Hub Interface (HI)
The proprietary interconnect between the Intel® 82854 GMCH and the ICH4-M
component. In this document, the Hub interface cycles originating from or
destined for the ICH4-M are generally referred to as “Hub interface cycles.” Hub
cycles originating from or destined for the primary PCI interface on are
sometimes referred to as “Hub interface/PCI cycles”
I2C
Inter-IC (a two wire serial bus created by Philips)
Integrated Graphics Device
IGD
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
Intel 82801DBM ICH4-M
The component contains the primary PCI interface, LPC interface, USB 2.0,
ATA-100, AC’97, and other I/O functions. It communicates with the Intel® 82854
GMCH over a proprietary interconnect called the Hub interface. Throughout this
datasheet, the Intel 82801DBM ICH4-M component will be referred to as the
ICH4-M
IPI
Inter Processor Interrupt
Liquid Crystal Display
LCD
MSI
Message Signaled Interrupts. MSI allow a device to request interrupt service via
a standard memory write transaction instead of through a hardware signal
Native Graphic Mode
The Intel® 82854 GMCH can support RGB and Dual Independent Display in this
mode
PWM
SD
Pulse Width Modulation
Standard definition, typically MP@ML for MPEG2
Spread Spectrum Clocking
Set Top Box
SSC
STB
System Bus
Processor-to-Intel® 82854 GMCH interface. The Enhanced mode of the
Scalable bus is the P6 Bus plus enhancements, consisting of source
synchronous transfers for address and data, and system bus interrupt delivery.
The Intel Celeron M processor implements a subset of Enhanced mode.
UMA
VDL
Unified Memory Architecture with graphics memory for the IGD inside system
memory
Video Data Link
18
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Introduction
1.3
Reference Documents
Table 2.
Reference Documents
Document
Location
Intel® Celeron® M Processor Datasheet
http://www.intel.com/design/mobile/datashts/300302.htm
Ultra Low Voltage Intel(R) Celeron(R) M
Processor at 600 MHz Addendum to the
Intel(R) Celeron(R) M Processor Datasheet
http://developer.intel.com/design/intarch/datashts/
301753.htm
Intel® 854 Chipset Platform Design Guide
for Use with Ultra Low Voltage Intel®
Celeron® M Processor at 600 MHz
Please contact your local Intel representative for this
document.
PCI Local Bus Specification 2.2
Intel® 82801DBM I/O Controller Hub 4
Mobile (ICH4-M) Datasheet
http://developer.intel.com/design/mobile/datashts/
Advanced Configuration and Power
Management (ACPI) Specification 1.0b &
2.0
IA-32 Intel® Architecture Software
Developer Manual Volume 3: System
Programming Guide
http://developer.intel.com/design/pentium4/manuals/
INTEL® DIGITAL VIDEO OUT (DVO) PORT
HARDWARE EXTERNAL DESIGN
SPECIFICATION (EDS) VER – 2.X
Please contact your local Intel representative for this
document.
ARIB TR-B15 Operational Guidelines for
Digital Satellite Broadcasting (detailed
Implementation guideline for receiver)
http://www.atsc.org/standards.html
ATSC Standards
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Intel 82854 GMCH Overview
®
2.0
Intel 82854 GMCH Overview
2.1
System Architecture
®
The Intel 82854 GMCH includes a processor interface, DDR SDRAM interface, display
interface, and Hub interface.
Combined with the ULV Intel® Celeron® M Processor or Genuine Intel® Processor, and an ICH4-
M, it provides many of the functions required to deliver the features below:
• Overall system software platform
• Graphic overlay function for the GUI and 3-D graphics for gaming.
• Soft CODEC function
• STB middleware execution
• New STB embedded applications requiring IA level of high performance.
®
2.1.1
Intel 82854 GMCH
®
The Intel 82854 GMCH is in a 732-pin Micro-FCBGA package that contains the following
functionality listed below:
• AGTL+ host bus supporting 32-bit host addressing with Enhanced Intel SpeedStep technology
support
• Supports a single channel of DDR SDRAM memory
• System memory supports DDR 266/333 MHz (SSTL_2) DDR SDRAM
• Integrated graphics capabilities: Graphic Core frequency at 200, 250 MHz
• Supports three display ports: one progressive scan analog monitor and two DVO ports.
• Enhanced Power Management Graphics features
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Intel 82854 Graphics Memory Controller Hub (GMCH)
2.2
Processor Host Interface
®
The Intel 82854 GMCH supports the Intel Celeron M Processor, and Genuine Intel Processor.
Key features of the front side bus (FSB) are:
• Support for a 400-MHz system bus frequency.
• Source synchronous double pumped address (2X)
• Source synchronous quad pumped data (4X)
• Front side bus interrupt delivery
• Low voltage swing Vtt (1.05 ~ 1.55V)
• Dynamic Power Down (DPWR#) support
• Integrates AGTL+ termination resistors on all of the AGTL+ signals
• Supports 32-bit host bus addressing allowing the CPU to access the entire 4 GB of the GMCH
memory address space.
• An 8-deep, In-Order queue
• Support DPWR# signal
• Supports one outstanding defer cycle at a time to any particular I/O interface
2.3
GMCH System Memory Interface
The GMCH system memory controller directly supports the following:
• One channel of PC2100/2700 DIMM DDR SDRAM memory
• DDR SDRAM devices with densities of 128-Mb, 256-Mb, and 512-Mb technology
• Up to 1 GB (512-Mb technology) with two DDR DIMMs
• Up to 2 GB (512-Mb technology) using high density devices with two DDR DIMMs
Table 3.
DDR SDRAM Memory Capacity
System Memory Capacity
with Stacked Memory
Technology
Width
System Memory Capacity
128 Mb
256 Mb
512 Mb
128 Mb
256 Mb
512 Mb
16
16
16
8
256 MB
512 MB
1 GB
-
-
-
256 MB
512 MB
1 GB
512 MB
1 GB
2 GB
8
8
The GMCH system memory interface supports a thermal throttling scheme to selectively throttle
reads and/or writes. Throttling can be triggered either by the on-die thermal sensor, or by preset
write bandwidth limits. Read throttle can also be triggered by an external input pin. The memory
controller logic supports aggressive Dynamic Row Power Down features to help reduce power and
supports Address and Control line tri-stating when DDR SDRAM is in an active power down or in
self refresh state.
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Intel 82854 GMCH Overview
The GMCH system memory architecture is optimized to maintain open pages (up to 16-KB page
size) across multiple rows. As a result, up to 16 pages across four rows is supported. To
complement this, the GMCH will tend to keep pages open within rows, or will only close a single
bank on a page miss. The GMCH supports only four bank memory technologies.
2.4
Graphics Features
The GMCH IGD provides a highly integrated graphics accelerator delivering high performance
2D, 3D, and video capabilities. With its interfaces to UMA using a DVMT configuration, an analog
display, and two digital display ports, the GMCH can provide a complete graphics solution.
The GMCH also provides 2D hardware acceleration for block transfers of data (BLTs). The BLT
engine provides the ability to copy a source block of data to a destination and perform raster
operations (for example, ROP1, ROP2, and ROP3) on the data using a pattern, and/or another
destination. Performing these common tasks in hardware reduces CPU load, and thus improves
performance.
High bandwidth access to data is provided through the system memory interface. The GMCH uses
Tiling architecture to increase system memory efficiency and thus maximize effective rendering
®
bandwidth. The Intel 82854 GMCH improves 3D performance and quality with 3D Zone
®
rendering technology. The Intel 82854 GMCH also supports Video Mixer rendering, and Bi-
Cubic filtering.
2.5
Display Features
®
The Intel 82854 GMCH has three display ports: one analog and two digital. With these interfaces,
the GMCH can provide support for a progressive scan analog monitor and two DVO ports. The
native graphic mode is able to deliver up to two streams of data via the two DVO ports.
2.5.1
GMCH Analog Display Port
®
The Intel 82854 GMCH has an integrated 350-MHz, 24-bit RAMDAC that can directly drive a
progressive scan analog monitor pixel resolution up to 1600x1200 at 85-Hz refresh and up to
2048x1536 at 75-Hz refresh. In the native graphic mode, the Analog display port can be driven by
Pipe A or Pipe B.
2.5.2
GMCH Integrated DVO Ports
®
The Intel 82854 GMCH provides a digital display channel that is capable of driving a pixel clock
up to 165 MHz.
The GMCH supports three ARIB planes of graphics: Still Picture Plane, Text and Graphic Plane,
and Superimpose Text Plane at a frame rate of 10 fps. A minimum of two displays are supported.
In native graphics mode, the GMCH supports a single display up to 60 fps real time with maximum
resolution of 720 x 480 pixels.
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
2.6
2.7
Hub Interface
A proprietary interconnect connects the GMCH to the ICH4-M. All communication between the
GMCH and the ICH4-M occurs over the Hub interface 1.5. The Hub interface runs at 66 MHz
(266-MB/s).
Address Decode Policies
Host initiated I/O cycles are positively decoded to the GMCH configuration space and
subtractively decoded to the Hub interface. Host initiated system memory cycles are positively
decoded to DDR SDRAM and are again subtractively decoded to the Hub interface, if less than
4 GB. System memory accesses from the Hub interface to DDR SDRAM will be snooped on
the FSB.
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Intel 82854 GMCH Overview
2.8
GMCH Clocking
The GMCH has the following clock input/output pins:
• 400-MHz, spread spectrum, low voltage differential BCLK, BCLK# for front side bus (FSB)
• 66-MHz, 3.3-V GCLKIN for Hub interface buffers
• Six pairs of differential output clocks (SCK[5:0], SCK[5:0]#), 200/266 MHz, 2.5 V for system
memory interface
• 48-MHz, non-Spread Spectrum, 3.3-V DREFCLK for the Display Frequency Synthesis
• 8-MHz or 66-MHz, Spread Spectrum, 3.3-V DREFSSCLK for the Display Frequency
Synthesis
• Up to 148.5 MHz, 1.5-V DVOBCCLKINT for TV-Out mode
• DPMS clock for S1-M
Clock Synthesizer chips are responsible for generating the system host clocks, GMCH display
clocks, Hub interface clocks, PCI clocks, SIO clocks, and FWH clocks. The host target speed is
400 MHz. The GMCH does not require any relationship between the BCLK Host clock and the
66-MHz clock generated for the Hub interface; they are asynchronous to each other. The Hub
the various interfaces that the GMCH supports.
®
Table 4.
Intel 82854 GMCH Interface Clocks
CPU System
Bus Frequency
Ratio
Data Rate
(Mega-
samples/s)
Data
Width
(Bytes)
Peak
Bandwidth
(MB/s)
Samples
Per Clock
Interface
Clock Speed
CPU Bus
100 MHz
133 MHz
166 MHz
Reference
4
2
2
2
400
266
333
330
8
8
3200
2128
2664
495
DDR SDRAM
1:1 Synchronous
1:1 Synchronous
Asynchronous
8
DVO B or DVO C
Up to 165
MHz
1.5
(Native Graphic
Mode)
DVO B+DVO C
Up to 330
MHz
Asynchronous
Asynchronous
2
1
660
350
3
3
1980
1050
(Native Graphic
Mode)
DAC Interface
350 MHz
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
2.9
System Interrupts
The GMCH supports both the legacy Intel 8259 Programmable Interrupt delivery mechanism and
the Intel Celeron M processor FSB interrupt delivery mechanism. The serial APIC Interrupt
mechanism is not supported.
The Intel 8259 Interrupt delivery mechanism support consists of flushing in bound Hub interface
write buffers when an Interrupt Acknowledge cycle is forwarded from the system bus to the Hub
interface.
PCI MSI interrupts are generated as memory writes. The GMCH decodes upstream memory writes
to the range 0FEE0_0000h - 0FEEF_FFFFh from the Hub interface as message based interrupts.
The GMCH forwards the memory writes along with the associated write data to the system bus as
an Interrupt Message transaction. Since this address does not decode as part of main system
memory, the write cycle and the write data do not get forwarded to system memory via the write
buffer. The GMCH provides the response and HTRDY# for all Interrupt Message cycles including
the ones originating from the GMCH. The GMCH also supports interrupt redirection for upstream
interrupt memory writes.
For message based interrupts, system write buffer coherency is maintained by relying on strict
ordering of memory writes. The GMCH ensures that all memory writes received from a given
interface prior to an interrupt message memory write are delivered to the system bus for snooping
in the same order that they occur on the given interface.
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Signal Description
3.0
Signal Description
®
This section describes the Intel 82854 GMCH signals. These signals are arranged in functional
groups according to their associated interface. The following notations are used to describe the
signal type.
Notation
Description
I
Input pin
O
I/O
Output pin
Bi-directional Input/Output pin
The signal description also includes the type of buffer used for the particular signal:
Buffer
Description
AGTL+
Open Drain AGTL+ interface signal. Refer to the AGTL+ I/O
Specification for complete details. The GMCH integrates AGTL+
termination resistors, and supports VTTLF of 1.05 V ± 5%. AGTL+
signals are "inverted bus" style where a low voltage represents a
logical 1.
DVO
DVO buffers (1.5-V tolerant)
Hub
Compatible to Hub interface 1.5
SSTL_2
LVTTL
CMOS
Analog
Ref
Stub Series Termination Logic compatible signals (2.5-V tolerant)
Low Voltage TTL compatible signals (3.3-V tolerant)
CMOS buffers (3.3-V tolerant)
Analog signal interface
Voltage reference signal
Note: System Address and Data Bus signals are logically inverted signals. In other words, the actual
values are inverted from what appears on the system bus. This must be taken into account and the
addresses and data bus signals must be inverted inside the GMCH. All processor control signals
follow normal convention: A 0 indicates an active level (low voltage), and a 1 indicates an active
level (high voltage).
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®
Intel 854 Graphics Memory Controller Hub (GMCH)
3.1
Host Interface Signals
Table 5.
Host Interface Signal Descriptions
Signal Name
ADS#
Type
I/O
Description
Address Strobe: The system bus owner asserts ADS# to indicate the
first of two cycles of a request phase. The GMCH can assert this signal
for snoop cycles and interrupt messages.
AGTL+
BNR#
BPRI#
I/O
AGTL+
Block Next Request: Used to block the current request bus owner from
issuing a new request. This signal is used to dynamically control the CPU
bus pipeline depth.
O
Bus Priority Request: The GMCH is the only Priority Agent on the
system bus. It asserts this signal to obtain the ownership of the address
bus. This signal has priority over symmetric bus requests and will cause
the current symmetric owner to stop issuing new transactions unless the
HLOCK# signal was asserted.
AGTL+
BREQ0#
I/O
AGTL+
Bus Request 0#: The GMCH pulls the processor bus BREQ0# signal
low during CPURST#. The signal is sampled by the processor on the
active-to-inactive transition of CPURST#. The minimum setup time for
this signal is 4 BCLKs. The minimum hold time is 2 clocks and the
maximum hold time is 20 BCLKs. BREQ0# should be tristated after the
hold time requirement has been satisfied.
During regular operation, the GMCH will use BREQ0# as an early
indication for FSB Address and Ctl input buffer and sense amp activation.
CPURST#
O
CPU Reset: The CPURST# pin is an output from the GMCH. The
GMCH asserts CPURST# while RESET# (PCIRST# from ICH4-M) is
asserted and for approximately 1 ms after RESET# is deasserted. The
CPURST# allows the processor to begin execution in a known state.
AGTL+
Note that the ICH4-M must provide CPU strap set-up and hold-times
around CPURST#. This requires strict synchronization between GMCH,
CPURST# deassertion and ICH4-M driving the straps.
DBSY#
I/O
Data Bus Busy: Used by the data bus owner to hold the data bus for
AGTL+
transfers requiring more than one cycle.
DEFER#
O
Defer: GMCH will generate a deferred response as defined by the rules
of the GMCH’s Dynamic Defer policy. The GMCH will also use the
DEFER# signal to indicate a CPU retry response.
AGTL+
DINV[3:0]#
I/O
AGTL+
Dynamic Bus Inversion: Driven along with the HD[63:0]# signals.
Indicates if the associated signals are inverted or not. DINV[3:0]# are
asserted such that the number of data bits driven electrically low (low
voltage) within the corresponding 16-bit group never exceeds 8.
DINV# Data Bits
DINV[3]# HD[63:48]#
DINV[2]# HD[47:32]#
DINV[1]# HD[31:16]#
DINV[0]# HD[16:0]#
DPSLP#
I
Deep Sleep #: This signal comes from the ICH4-M device, providing an
indication of C3 and C4 state control to the CPU. Deassertion of this
signal is used as an early indication for C3 and C4 wake up (to active
HPLL). Note that this is a low-voltage CMOS buffer operating on the FSB
VTT power plane.
CMOS
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Signal Description
DRDY#
I/O
Data Ready: Asserted for each cycle that data is transferred.
AGTL+
HA[31:3]#
I/O
AGTL+
Host Address Bus: HA[31:3]# connects to the CPU address bus. During
processor cycles the HA[31:3]# are inputs. The GMCH drives HA[31:3]#
during snoop cycles on behalf of Hub interface. HA[31:3]# are
transferred at 2x rate. Note that the address is inverted on the CPU bus.
HADSTB[1:0]#
I/O
AGTL+
Host Address Strobe: HA[31:3]# connects to the CPU address bus.
During CPU cycles, the source synchronous strobes are used to transfer
HA[31:3]# and HREQ[4:0]# at the 2x transfer rate.
Strobe
Address Bits
HADSTB[0]#
HADSTB[1]#
HA[16:3]#, HREQ[4:0]#
HA[31:17]#
HD[63:0]#
I/O
AGTL+
Host Data: These signals are connected to the CPU data bus.
HD[63:0]# are transferred at 4x rate. Note that the data signals are
inverted on the CPU bus.
HDSTBP[3:0]#
HDSTBN[3:0]#
I/O
AGTL+
Differential Host Data Strobes: The differential source synchronous
strobes are used to transfer HD[63:0]# and DINV[3:0]# at the 4x
transfer rate.
Strobe
Data Bits
HDSTBP[3]#, HDSTBN[3]#
HDSTBP[2]#, HDSTBN[2]#
HDSTBP[1]#, HDSTBN[1]#
HDSTBP[0]#, HDSTBN[0]#
HD[63:48]#, DINV[3]#
HD[47:32]#, DINV[2]#
HD[31:16]#, DINV[1]#
HD[15:0]#, DINV[0]#
HIT#
I/O
AGTL+
Hit: Indicates that a caching agent holds an unmodified version of the
requested line. Also, driven in conjunction with HITM# by the target to
extend the snoop window.
HITM#
I/O
AGTL+
Hit Modified: Indicates that a caching agent holds a modified version of
the requested line and that this agent assumes responsibility for
providing the line. Also, driven in conjunction with HIT# to extend the
snoop window.
HLOCK#
I/O
AGTL+
Host Lock: All CPU bus cycles sampled with the assertion of HLOCK#
and ADS#, until the negation of HLOCK# must be atomic; that is, no Hub
interface snoopable access to system memory is allowed when HLOCK#
is asserted by the CPU.
HREQ[4:0]#
I/O
AGTL+
Host Request Command: Defines the attributes of the request.
HREQ[4:0]# are transferred at 2x rate. Asserted by the requesting agent
during both halves of the Request Phase. In the first half the signals
define the transaction type to a level of detail that is sufficient to begin a
snoop request. In the second half the signals carry additional information
to define the complete transaction type.
The transactions supported by the GMCH Host Bridge are defined in the
Host Interface section of this document.
HTRDY#
O
Host Target Ready: Indicates that the target of the processor
AGTL+
transaction is able to enter the data transfer phase.
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Intel 854 Graphics Memory Controller Hub (GMCH)
RS[2:0]#
O
Response Status: Indicates the type of response according to the
AGTL+
following the table:
RS[2:0]#
000
Response type
Idle state
001
Retry response
010
Deferred response
Reserved (not driven by GMCH)
Hard Failure (not driven by GMCH)
No data response
011
100
101
110
Implicit Write back
111
Normal data response
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Signal Description
3.2
DDR SDRAM Interface
Table 6.
DDR SDRAM Interface Descriptions
Signal Name
SCS[3:0]#
Type
Description
O
Chip Select: These pins select the particular DDR SDRAM
SSTL_2
components during the active state.
NOTE: There is one SCS# per DDR-SDRAM Physical DDR DIMM
device row. These signals can be toggled on every rising System
Memory Clock edge (SCMDCLK).
SMA[12:0]
SBA[1:0]
O
Multiplexed Memory Address: These signals are used to provide the
multiplexed row and column address to the DDR SDRAM.
SSTL_2
O
Bank Select (Memory Bank Address): These signals define which
banks are selected within each DDR SDRAM row. The SMA and SBA
signals combine to address every possible location within a DDR
SDRAM device.
SSTL_2
SRAS#
SCAS#
SWE#
O
DDR Row Address Strobe: SRAS# may be heavily loaded and
requires tw0 DDR SDRAM clock cycles for setup time to the DDR
SDRAMs. Used with SCAS# and SWE# (along with SCS#) to define the
system memory commands.
SSTL_2
O
DDR Column Address Strobe: SCAS# may be heavily loaded and
requires two clock cycles for setup time to the DDR SDRAMs. Used
with SRAS# and SWE# (along with SCS#) to define the system memory
commands.
SSTL_2
O
Write Enable: Used with SCAS# and SRAS# (along with SCS#) to
define the DDR SDRAM commands. SWE# is asserted during writes to
DDR SDRAM. SWE# may be heavily loaded and requires two clock
cycles for setup time to the DDR SDRAMs.
SSTL_2
SDQ[63:0]
SDQS[8:0]
I/O
SSTL_2
Data Lines: These signals are used to interface to the DDR SDRAM
data bus.
I/O
SSTL_2
Data Strobes: Data strobes are used for capturing data. During writes,
SDQS is centered on data. During reads, SDQS is edge aligned with
data. The following list matches the data strobe with the data bytes.
There is an associated data strobe (DQS) for each data signal (DQ) and
check bit (CB) group.
SDQS[7] -> SDQ[63:56]
SDQS[6] -> SDQ[55:48]
SDQS[5] -> SDQ[47:40]
SDQS[4] -> SDQ[39:32]
SDQS[3] -> SDQ[31:24]
SDQS[2] -> SDQ[23:16]
SDQS[1] -> SDQ[15:8]
SDQS[0] -> SDQ[7:0]
SCKE[3:0]
O
Clock Enable: These pins are used to signal a self-refresh or power
down command to the DDR SDRAM array when entering system
suspend. SCKE is also used to dynamically power down inactive DDR
SDRAM rows. There is one SCKE per DDR SDRAM row. These
signals can be toggled on every rising SCK edge.
SSTL_2
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Intel 854 Graphics Memory Controller Hub (GMCH)
SMAB[5,4,2,1]
SDM[8:0]
O
Memory Address Copies: These signals are identical to SMA[5,4,2,1]
and are used to reduce loading for selective CPC(clock-per-command).
These copies are not inverted.
SSTL_2
O
Data Mask: When activated during writes, the corresponding data
groups in the DDR SDRAM are masked. There is one SDM for every
eight data lines. SDM can be sampled on both edges of the data
strobes.
SSTL_2
RCVENOUT#
RCVENIN#
O
Clock Output: Reserved, NC.
SSTL_2
O
Clock Input: Reserved, NC.
SSTL_2
3.3
Hub Interface Signals
Table 7.
Hub Interface Signals
Signal Name
Type
Description
HL[10:0]
HLSTB
I/O Hub
I/O Hub
Packet Data: Data signals used for HI read and write operations.
Packet Strobe: One of two differential strobe signals used to transmit or
receive packet data over HI.
HLSTB#
I/O Hub
Packet Strobe Complement: One of two differential strobe signals used
to transmit or receive packet data over HI.
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Signal Description
3.4
Clocks
Table 8.
Clock Signals
Signal Name
Type
Description
Host Processor Clocking
BCLK
I
Differential Host Clock In: These pins receive a buffered host clock
from the external clock synthesizer. This clock is used by all of the
GMCH logic that are in the Host clock domain (Host, Hub and system
memory). The clock is also the reference clock for the graphics core
PLL. This is a low voltage differential input.
BCLK#
CMOS
System Memory Clocking
SCK[5:0]
O
Differential DDR SDRAM Clock: SCK and SCK# pairs are differential
clock outputs. The crossing of the positive edge of SCK and the
negative edge of SCK# is used to sample the address and control
signals on the DDR SDRAM. There are 3 pairs to each DDR DIMM.
SSTL_2
SCK[5:0]#
O
Complementary Differential DDR SDRAM Clock: These are the
complimentary differential DDR SDRAM clock signals.
SSTL_2
DVO/Hub Input Clocking
GCLKIN
I
Input Clock: 66-MHz, 3.3-V input clock from external buffer DVO/Hub
interface.
CMOS
DVO Clocking
DVOBCLK
O
Differential DVO Clock Output: These pins provide a differential pair
DVOBCLK#
reference clock that can run up to 165-MHz.
DVO
DVOBCLK corresponds to the primary clock out.
DVOBCLK# corresponds to the primary complementary clock out.
DVOBCLK and DVOBCLK# should be left as NC (“Not Connected”) if
the DVO B port is not implemented.
DVOCCLK
O
Differential DVO Clock Output: These pins provide a differential pair
DVOCCLK#
reference clock that can run up to 165-MHz.
DVO
DVOCCLK corresponds to the primary clock out.
DVOCCLK# corresponds to the primary complementary clock out.
DVOCCLK and DVOCCLK# should be left as NC (“Not Connected”) if
the DVO C port is not implemented.
DVOBCCLKINT
I
DVOBC Pixel Clock Input/Interrupt: This signal may be selected as
the reference input to either dot clock PLL (DPLL) or may be
configured as an interrupt input. A TV-out device can provide the clock
reference. The maximum input frequency for this signal is 148.5 -MHz.
DVO
DVOBC Pixel Clock Input: When selected as the dot clock PLL (DPLL)
reference input, this clock reference input supports SSC clocking for
DVO LVDS devices.
DVOBC Interrupt: When configured as an interrupt input, this interrupt
can support either DVOB or DVOC.
DVOBCCLKINT needs to be pulled down if the signal is NOT used.
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®
Intel 854 Graphics Memory Controller Hub (GMCH)
DPMS
I
Display Power Management Signaling: This signal is used only in
mobile systems to act as the DREFCLK in certain power management
states (i.e., Display Power Down Mode); DPMS Clock is used to
refresh video during S1-M. Clock Chip is powered down in S1-M.
DPMS should come from a clock source that runs during S1-M and
needs to be 1.5 V. So, an example would be to use a 1.5-V version of
SUSCLK from ICH4-M.
DVO
DAC Clocking
DREFCLK
I
Display Clock Input: This pin is used to provide a 48-MHz input clock
to the Display PLL that is used for 2D/Video and DAC.
LVTTL
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Signal Description
3.5
Internal Graphics Display Signals
The IGD has support for DVOB/C interfaces, and an Analog CRT port.Digital Video Output B
(DVOB) Port.
3.5.1
Digital Video Output B (DVOB) Port
Table 9.
Digital Video Output B (DVOB) Port Signal Descriptions
Name
Type
Description
DVOBD[11:0]
O
DVOB Data: This data bus is used to drive 12-bit RGB data on each edge
of the differential clock signals, DVOBCLK and DVOBCLK#. This provides
24-bits of data per clock period. In dual channel mode, this provides the
lower 12-bits of pixel data.
DVO
DVOBD[11:0] should be left as NC (“Not Connected”) if not used.
DVOBHSYNC
DVOBVSYNC
O
Horizontal Sync: HSYNC signal for the DVOB interface.
DVO
DVOBHSYNC should be left as left as NC (“Not Connected”) if not used.
O
Vertical Sync: VSYNC signal for the DVOB interface.
DVO
DVOBVSYNC should be left as left as NC (“Not Connected”) if the signal
is NOT used when using internal graphics device.
DVOBBLANK#
DVOBFLDSTL
O
Flicker Blank or Border Period Indication: DVOBBLANK# is a
programmable output pin driven by the GMCH.
DVO
When programmed as a blank period indication, this pin indicates active
pixels excluding the border. When programmed as a border period
indication, this pin indicates active pixel including the border pixels.
DVOBBLANK# should be left as left as NC (“Not Connected”) if not used.
I
TV Field and Flat Panel Stall Signal. This input can be programmed to
be either a TV Field input from the TV encoder or Stall input from the flat
panel.
DVO
DVOB TV Field Signal: When used as a Field input, it synchronizes the
overlay field with the TV encoder field when the overlay is displaying an
interleaved source.
DVOB Flat Panel Stall Signal: When used as the Stall input, it indicates
that the pixel pipeline should stall one horizontal line. The signal changes
during horizontal blanking. The panel fitting logic, when expanding the
image vertically, uses this.
DVOBFLDSTL needs to be pulled down if not used.
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Intel 854 Graphics Memory Controller Hub (GMCH)
3.5.2
Digital Video Output C (DVOC) Port
Table 10.
Digital Video Output C (DVOC) Port Signal Descriptions
Name
Type
Description
DVOCD[11:0]
O
[Native Graphic Mode]
DVO
DVOC Data: This data bus is used to drive 12-bit RGB data on each edge
of the differential clock signals, DVOCCLK and DVOCCLK#. This
provides 24-bits of data per clock period. In dual channel mode, this
provides the upper 12-bits of pixel data.
DVOCD[11:0] should be left as left as NC (“Not Connected”) if not used.
DVOCHSYNC
DVOCVSYNC
O
Horizontal Sync: HSYNC signal for the DVOC interface.
DVO
DVOCHSYNC should be left as left as NC (“Not Connected”) if not used.
O
Vertical Sync: VSYNC signal for the DVOC interface.
DVO
DVOCVSYNC should be left as left as NC (“Not Connected”) if the signal
is NOT used when using internal graphics device.
DVOCBLANK#
DVOCFLDSTL
O
Flicker Blank or Border Period Indication: DVOCBLANK# is a
programmable output pin driven by the GMCH.
DVO
When programmed as a blank period indication, this pin indicates active
pixels excluding the border. When programmed as a border period
indication, this pin indicates active pixel including the border pixels.
DVOCBLANK# should be left as left as NC (“Not Connected”) if not used.
I
TV Field and Flat Panel Stall Signal. This input can be programmed to
be either a TV Field input from the TV encoder or Stall input from the flat
panel.
DVO
DVOC TV Field Signal: When used as a Field input, it synchronizes the
overlay field with the TV encoder field when the overlay is displaying an
interleaved source.
DVOC Flat Panel Stall Signal: When used as the Stall input, it indicates
that the pixel pipeline should stall one horizontal line. The signal changes
during horizontal blanking. The panel fitting logic, when expanding the
image vertically, uses this.
DVOCFLDSTL needs to be pulled down if not used.
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Signal Description
Table 11.
DVOB and DVOC Port Common Signal Descriptions
Name
Type
Description
DVOBCINTR#
I
DVOBC Interrupt: This pin is used to signal an interrupt, typically used to
indicate a hot plug or unplug of a digital display.
DVO
ADDID[7:0]
I
ADDID[7:0]: These pins are used to communicate to the Video BIOS
when an external device is interfaced to the DVO port.
DVO
Note: Bit[7] needs to be strapped low when an on-board DVO device is
present. The other pins should be left as NC.
ADDID[0] = 0, Reserve
ADDID[0] = 1, the Intel® 82854 GMCH is strapped to operate under
Native Graphic Mode
DVODETECT
I
DVODETECT: This strapping signal indicates to the GMCH whether a
DVO device is present or not. When a DVO device is connected, then
DVODETECT = 0.
DVO
3.5.3
Analog CRT Display
Table 12.
Analog CRT Display Signal Descriptions
Pin Name
VSYNC
Type
Description
O
CRT Vertical Synchronization: This signal is used as the vertical sync signal.
CMOS
HSYNC
RED
O
CRT Horizontal Synchronization: This signal is used as the horizontal sync
signal.
CMOS
O
Red (Analog Video Output): This signal is a CRT Analog video output from
the internal color palette DAC. The DAC is designed for a 37.5-Ω equivalent
load on each pin (that is, a 75-Ω resistor on the board, in parallel with the 75-Ω
CRT load).
Analog
RED#
O
Red# (Analog Output): Tied to ground.
Analog
GREEN
O
Green (Analog Video Output): This signal is a CRT analog video output from
the internal color palette DAC. The DAC is designed for a 37.5-Ω equivalent
load on each pin (that is, a 75-Ω resistor on the board, in parallel with the 75- Ω
CRT load).
Analog
GREEN#
O
Green# (Analog Output): Tied to ground.
Analog
Blue (Analog Video Output) : This signal is a CRT Analog video output from
the internal color palette DAC. The DAC is designed for a 37.5-Ω equivalent
load on each pin (that is, a 75-ohm resistor on the board, in parallel with the 75-
Ω CRT load).
O
BLUE
Analog
O
Blue# (Analog Output): Tied to ground.
BLUE#
Analog
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Intel 854 Graphics Memory Controller Hub (GMCH)
3.5.4
General Purpose Input/Output Signals
Table 13.
GPIO Signal Descriptions
GPIO I/F Total
RSTIN#
Type
Comments
I
Reset: Primary Reset, Connected to PCIRST# of ICH4-M.
CMOS
PWROK
I
Power OK: Indicates that power to GMCH is stable.
CMOS
EXTTS_0
I
External Thermal Sensor Input: This signal is an active low input to the
GMCH and is used to monitor the thermal condition around the system memory
and is used for triggering a read throttle. The GMCH can be optionally
programmed to send a SERR, SCI, or SMI message to the ICH4-M upon the
triggering of this signal.
CMOS
LCLKCTLA
LCLKCTLB
O
SSC Chip Clock Control: Can be used to control an external clock chip with
SSC control.
CMOS
O
SSC Chip Data Control: Can be used to control an external clock chip for
SSC control.
CMOS
I/O
DDCACLK
CRT DDC Clock: This signal is used as the DDC clock signal between the
CRT monitor and the GMCH.
CMOS
I/O
DDCADATA
CRT DDC Data: This signal is used as the DDC data signal between the CRT
monitor and the GMCH.
CMOS
MI2CCLK
I/O
DVO I2C Clock: This signal is used as the I2C_CLK for a digital display (i.e.
TV-Out Encoder, TMDS transmitter). This signal is tri-stated during a hard
reset.
DVO
MI2CDATA
MDVICLK
MDVIDATA
MDDCDATA
MDDCCLK
I/O
DVO I2C Data: This signal is used as the I2C_DATA for a digital display (i.e.
TV-Out Encoder, TMDS transmitter). This signal is tri-stated during a hard
reset.
DVO
I/O
DVI DDC Clock: This signal is used as the DDC clock for a digital display
connector (that is, primary digital monitor). This signal is tri-stated during a hard
reset.
DVO
I/O
DVI DDC Data: The signal is used as the DDC data for a digital display
connector (that is, the primary digital monitor). This signal is tri-stated during a
hard reset.
DVO
I/O
DVI DDC Clock: The signal is used as the DDC data for a digital display
connector (that is, the secondary digital monitor). This signal is tri-stated during
a hard reset.
DVO
I/O
DVI DDC Data: The signal is used as the DDC clock for a digital display
connector (that is, the secondary digital monitor). This signal is tri-stated during
a hard reset.
DVO
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Signal Description
3.6
Voltage References, PLL Power
Table 14.
Voltage References, PLL Power
Signal Name
Type
Description
Host Processor
HXRCOMP
HYRCOMP
HXSWING
Analog
Host RCOMP: Used to calibrate the Host AGTL+ I/O buffers.
Host RCOMP: Used to calibrate the Host AGTL+ I/O buffers.
Analog
Analog
Host Voltage Swing (RCOMP reference voltage): This signal provides
a reference voltage used by the FSB RCOMP circuit.
HYSWING
Analog
Host Voltage Swing (RCOMP reference voltage): This signal provides
a reference voltage used by the FSB RCOMP circuit.
HDVREF[2:0]
Ref
Analog
Host Data (input buffer) VREF: Reference voltage input for the data
signals of the Host AGTL+ Interface. Input buffer differential amplifier to
determine a high versus low input voltage.
HAVREF
Ref
Analog
Host Address (input buffer) VREF: Reference voltage input for the
address signals of the Host AGTL+ Interface. This signal is connected to
the input buffer differential amplifier to determine a high versus low input
voltage.
HCCVREF
Ref Analog
Host Common Clock (Command input buffer) VREF: Reference
voltage input for the common clock signals of the Host AGTL+ Interface.
This signal is connected to the input buffer differential amplifier to
determine a high versus low input voltage.
VTTLF
VTTHF
Power
Power
FSB Power Supply: VTTLF is the low frequency connection from the
board. This signal is the primary connection of power for GMCH.
FSB Power Supply: VTTHF is the high frequency supply. It is for direct
connection from an internal package plane to a capacitor placed
immediately adjacent to the GMCH.
NOTE: Not to be connected to power rail.
System Memory
SMRCOMP
Analog
System Memory RCOMP: This signal is used to calibrate the memory I/
O buffers.
SMVREF_0
Ref
Memory Reference Voltage(Input buffer VREF):Reference voltage
Analog
input for Memory Interface.
Input buffer differential amplifier to determine a high versus low input
voltage.
SMVSWINGH
SMVSWINGL
Ref
Analog
RCOMP reference voltage: This is connected to the RCOMP buffer
differential amplifier and is used to calibrate the I/O buffers.
Ref
RCOMP reference voltage: This is connected to the RCOMP buffer
Analog
differential amplifier and is used to calibrate the I/O buffers.
VCCSM
Power
Power
Power
Power supply for Memory I/O.
VCCQSM
VCCASM
Power supply for system memory clock buffers.
Power supply for system memory logic running at the core voltage
(isolated supply, not connected to the core).
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®
Intel 854 Graphics Memory Controller Hub (GMCH)
Hub Interface
HLRCOMP
PSWING
HLVREF
Analog
Analog
Hub Interface RCOMP: This signal is connected to a reference resistor
in order to calibrate the buffers.
RCOMP reference voltage: This is connected to the RCOMP buffer
differential amplifier and is used to calibrate the buffers.
Ref
Input buffer VREF: Input buffer differential amplifier to determine a high
versus low input voltage.
Analog
VCCHL
Power
Power supply for Hub interface buffers
DVO
DVORCOMP
Analog
Analog
Compensation for DVO: This signal is used to calibrate the DVO I/O
buffers.
GVREF
Ref Analog
Power
Input buffer VREF: Input buffer differential amplifier to determine a high
versus low input voltage.
VCCDVO
GPIO
Power supply for DVO.
VCCGPIO
DAC
Power
Power supply for GPIO buffers
REFSET
Ref
Resistor Set: Set point resistor for the internal color palette DAC.
Analog
VCCADAC
VSSADAC
IGD
Power
Power
Power supply for the DAC
Ground supply for the DAC
VCC1_5
VCC2_5
VCCA
Power
Power
Power
Power
Digital power supply.
Digital power supply
Analog power supply.
Ground supply
VSSA
Clocks
VCCAHPLL
VCCAGPLL
VCCADPLLA
VCCADPLLB
Core
Power
Power
Power
Power
Power supply for the Host PLL.
Power supply for the Hub/DVO PLL.
Power supply for the display PLL A.
Power supply for the display PLL B.
VCC
Power
Power
Power supply for the core.
Ground supply for the chip.
VSS
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Register Description
4.0
Register Description
4.1
Conceptual Overview of the Platform Configuration
Structure
The GMCH and ICH4-M are physically connected by a Hub interface. From a configuration
standpoint, the Hub interface is logically PCI bus #0. As a result, all devices internal to the GMCH
and ICH4-M appear to be on PCI bus #0. The system's primary PCI expansion bus is physically
attached to the ICH4-M and from a configuration perspective, appears to be a hierarchical PCI bus
behind a PCI-to-PCI bridge and therefore has a programmable PCI Bus number. Note that the
primary PCI bus is referred to as PCI_A in this document and is not PCI bus #0 from a
configuration standpoint. For the GMCH, the graphics subsystem appears to system software to be
a real PCI bus behind PCI-to-PCI bridges, resident as devices on PCI bus #0.
The GMCH contains two PCI devices within a single physical component. The configuration
registers for the two devices are mapped as devices residing on PCI bus #0.
Device #0: Host-Hub Interface Bridge/DDR SDRAM Controller. Logically this appears as a PCI
device residing on PCI bus #0. Physically, Device #0 contains the standard PCI registers, DDR
SDRAM registers, the Graphics Aperture Controller registers, HI Control registers and other
GMCH specific registers. Device #0 is divided into the following functions:
Function #0: Host Bridge Legacy registers including Graphics Aperture Control registers, HI
Configuration registers and Interrupt Control registers
Function #1: DDR SDRAM Interface Registers
Function #3: Intel Configuration Process Registers
Device #2: Integrated Graphics Controller. Logically this appears as a PCI device residing on PCI
bus #0. Physically Device #2 contains the Configuration registers for 2D, 3D, and display
functions.
®
Note: The legacy VGA registers are only supported when the Intel 82854 GMCH is strapped into
Native Graphics Mode.
Table 15 shows the Device # assignment for the various internal GMCH devices.
Table 15.
Device Number Assignment
GMCH Function
Bus #0, Device#
Host-Hub interface, DDR SDRAM I/F, Legacy control
Integrated Graphics Controller (IGD)
Device #0
Device #2
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Intel 82854 Graphics Memory Controller Hub (GMCH)
4.2
Nomenclature for Access Attributes
Table 16 provides the nomenclature for the access attributes.
Table 16.
Nomenclature for Access Attributes
RO
Read Only. If a register is Read Only, Writes to this register have no effect.
R/W
Read/Write. A register with this attribute can be Read and Written.
R/W/L
R/WC
Read/Write/Lock. A register with this attribute can be Read, Written, and Locked.
Read/Write Clear. A register bit with this attribute can be Read and Written.
However, a Write of a 1 clears (sets to 0) the corresponding bit and a Write of a 0
has no effect.
R/WO
Read/Write Once. A register bit with this attribute can be Written to only once
after power up. After the first Write, this bit becomes Read Only.
L
Lock. A register bit with this attribute becomes Read Only after a Lock bit is set.
Reserved Bits
Some of the GMCH registers described in this section contain Reserved bits.
These bits are labeled "Reserved”. Software must deal correctly with fields that are
Reserved. On Reads, software must use appropriate masks to extract the defined
bits and not rely on Reserved bits being of any particular value. On Writes,
software must ensure that the values of Reserved bit positions are preserved. That
is, the values of Reserved bit positions must first be Read, Merged with the new
values for other bit positions and then Written back. Note the software does not
need to perform Read, Merge, and Write operations for the Configuration Address
register.
Reserved Registers
In addition to Reserved bits within a register, the GMCH contains address locations
in the configuration space of the Host-Hub Interface Bridge entity that are marked
either "Reserved" or “Intel Reserved”. The GMCH responds to accesses to
“Reserved” address locations by completing the Host cycle. When a “Reserved”
register location is Read, in certain cases, a zero value can be returned
(“Reserved” registers can be 8-bit, 16-bit, or 32-bit in size) or a non-zero value can
be returned. In certain cases, Writes to “Reserved” registers may have no effect on
the GMCH or may cause system failure. Registers that are marked as “Intel
Reserved” must not be modified by system software.
Default Value upon a
Reset
Upon Reset, the GMCH sets all of its internal configuration registers to
predetermined default states. Some register values at Reset are determined by
external strapping options. The default state represents the minimum functionality
feature set required to successfully bring up the system. Hence, it does not
represent the optimal system configuration. It is the responsibility of the system
initialization software (usually BIOS) to properly determine the DDR SDRAM
configurations, operating parameters and optional system features that are
applicable, and to program the GMCH registers accordingly.
S
SW Semaphore.
A physical PCI Bus #0 does not exist. The Hub interface and the internal devices in the GMCH and
ICH4-M logically constitute PCI Bus #0 to configuration software.
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Register Description
4.3
Standard PCI Bus Configuration Mechanism
The PCI Bus defines a slot based “configuration space” that allows each device to contain up to
eight functions with each function containing up to 256, 8-bit configuration registers. The PCI
Specification defines two bus cycles to access the PCI Configuration Space: Configuration Read
and Configuration Write. Memory and I/O spaces are supported directly by the CPU.
Configuration Space is supported by a mapping mechanism implemented within the GMCH. The
PCI 2.2 specification defines two mechanisms to access Configuration Space: Mechanism #1 and
Mechanism #2. The GMCH supports only Mechanism #1.
The Configuration Access Mechanism makes use of the CONFIG_ADDRESS register (at I/O
address 0CF8h though 0CFBh) and CONFIG_DATA register (at I/O address 0CFCh though
0CFFh). To reference a Configuration register a Dword I/O Write cycle is used to place a value
into CONFIG_ADDRESS that specifies the PCI Bus, the device on that bus, the function within
the device, and a specific Configuration register of the device function being accessed.
CONFIG_ADDRESS[31] must be a 1 to enable a Configuration cycle. CONFIG_DATA then
becomes a window into the four Bytes of Configuration Space specified by the contents of
CONFIG_ADDRESS. Any Read or Write to CONFIG_DATA will result in the GMCH translating
the CONFIG_ADDRESS into the appropriate Configuration cycle.
The GMCH is responsible for translating and routing the CPU’s I/O accesses to the
CONFIG_ADDRESS and CONFIG_DATA registers to internal GMCH Configuration registers
and to the Hub interface.
4.4
Routing Configuration Accesses
The GMCH supports one bus interface: the Hub interface. PCI Configuration cycles are selectively
routed to this interface. The GMCH is responsible for routing PCI Configuration cycles to the
proper interface. PCI configuration cycles to the ICH4-M internal devices, and Primary PCI
(including downstream devices) are routed to theICH4-M via the Hub interface.
4.4.1
PCI Bus #0 Configuration Mechanism
The GMCH decodes the Bus Number (bits 23:16) and the Device Number fields of the
CONFIG_ADDRESS register. If the Bus Number field of CONFIG_ADDRESS is 0, then the
Configuration cycle is targeting a PCI Bus #0 device.
The Host-Hub Interface Bridge entity within the GMCH is hardwired as Device #0 on PCI Bus #0.
Configuration cycles to any of the GMCH’s internal devices are confined to the GMCH and not
sent over Hub interface. Accesses to disabled GMCH internal devices will be forwarded over the
Hub interface as Type 0 Configuration cycles.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
4.4.2
Primary PCI and Downstream Configuration Mechanism
If the Bus Number in the CONFIG_ADDRESS is non-zero, the GMCH will generate a Type 1 Hub
interface Configuration Cycle. A[1:0] of the Hub interface request packet for the Type 1
configuration cycle will be “01”. This Hub interface configuration cycle will be sent over Hub
interface.
If the cycle is forwarded to the ICH4-M via Hub interface, the ICH4-M compares the non-zero Bus
Number with the Secondary bus number and Subordinate bus number registers of its PCI-to-PCI
bridges to determine if the configuration cycle is meant for Primary PCI, one of the ICH4-M’s Hub
interfaces, or a downstream PCI bus.
4.5
Register Definitions
The GMCH contains four sets of software accessible registers accessed via the Host CPU I/O
Address Space, and they are as follows:
• Control registers: I/O Mapped into the CPU I/O Space, which control access to PCI
Configuration Space via Configuration Mechanism #1 in the PCI 2.2 specification.
• Internal Configuration registers: residing within the GMCH, they are partitioned into two
logical device register sets (“logical” since they reside within the single physical device). The
first register set is dedicated to Host-HI Bridge functionality (that is, DDR SDRAM
configuration, other chip-set operating parameters and optional features). The second register
block is for the integrated graphics functions.
• Internal Memory Mapped Configuration registers: reside in the GMCH Device #0.
• Internal Memory Mapped Configuration registers, Legacy VGA registers, or blending
function registers: reside in the GMCH Device #2 that controls the Integrated Graphics
Controller.
The GMCH internal registers (I/O Mapped and Configuration registers) are accessible by the Host
CPU. The registers can be accessed as Byte, Word (16-bit), or Dword (32-bit) quantities, with the
exception of CONFIG_ADDRESS, which can only be accessed as a Dword. All multi-byte
numeric fields use “Little Endian Byte Ordering” (that is, lower addresses contain the least
significant parts of the field).
Reserved Bits
Some of the GMCH registers described in this section contain Reserved bits. These bits are labeled
“Reserved”. Software must deal correctly with fields that are Reserved. On Reads, software must
use appropriate Masks to extract the defined bits and not rely on Reserved bits being any particular
value. On Writes, software must ensure that the values of Reserved bit positions are preserved.
That is, the values of Reserved bit positions must first be Read, Merged with the new values for
other bit positions and then Written back.
Note: The software does not need to perform Read, Merge, and Write operations for the Configuration
Address register.
Default Value upon Reset
Upon a Full Reset, the GMCH sets all of its Internal Configuration registers to a predetermined
default state. Some register values at Reset are determined by external strapping options. The
default state represents the minimum functionality feature set required to successfully bring up the
system. Hence, it does not represent the optimal system configuration. It is the responsibility of the
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Register Description
system initialization software (usually BIOS) to properly determine the DDR SDRAM
configurations, operating parameters, and optional system features that are applicable and to
program the GMCH registers accordingly.
4.6
I/O Mapped Registers
The GMCH contains two registers that reside in the CPU I/O Address Space: the Configuration
Address (CONFIG_ADDRESS) Register and the Configuration Data (CONFIG_DATA) Register.
The Configuration Address Register enables/disables the Configuration Space and determines
what portion of Configuration Space is visible through the Configuration Data window.
4.6.1
CONFIG_ADDRESS – Configuration Address Register
I/O Address:
Default Value:
Access:
0CF8h Accessed as a Dword
00000000h
Read/Write
Size:
32 bits
CONFIG_ADDRESS is a 32-bit register that can be accessed only as a Dword. A Byte or Word
reference will “pass through” the Configuration Address Register and the Hub interface, onto the
PCI bus as an I/O cycle. The CONFIG_ADDRESS register contains the Bus Number, Device
Number, Function Number, and Register Number for which a subsequent configuration access is
intended.
Figure 2.
Configuration Address Register
Bit
Default
31 30 24 23 16 15 11 10
8 7
2 1 0
R
R
0
0
0
0
0
Reserved
Register Number
Function Number
Device Number
Bus Number
Reserved
Enable
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Intel 82854 Graphics Memory Controller Hub (GMCH)
Bit
Descriptions
31
Configuration Enable (CFGE): When this bit is set to 1, accesses to PCI Configuration Space
are enabled. If this bit is Reset to 0, accesses to PCI Configuration Space are disabled.
30:24
23:16
Reserved
Bus Number: When the Bus Number is programmed to 00h, the target of the Configuration
Cycle is a Hub interface agent (GMCH, ICH4-M, and so on.).
The Configuration Cycle is forwarded to Hub interface if the Bus Number is programmed to 00h
and the GMCH is not the target (the device number is >= 2).
15:11
10:8
Device Number: This field selects one agent on the PCI Bus selected by the Bus Number. When
the Bus Number field is 00 the GMCH decodes the Device Number field. The GMCH is always
Device Number 0 for the Host-Hub interface bridge entity. Therefore, when the Bus Number =0
and the Device Number=0-1 the internal GMCH devices are selected.
For Bus Numbers resulting in Hub interface Configuration cycles, the GMCH propagates the
device number field as A[15:11].
Function Number: This field is mapped to A[10:8] during Hub interface Configuration cycles.
This allows the configuration registers of a particular function in a multi-function device to be
accessed. The GMCH ignores Configuration cycles to its internal Devices if the function number is
not equal to 0.
7:2
1:0
Register Number: This field selects one register within a particular Bus, Device, and Function as
specified by the other fields in the Configuration Address register. This field is mapped to A[7:2]
during Hub interface Configuration cycles.
Reserved
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Register Description
4.6.2
CONFIG_DATA – Configuration Data Register
I/O Address:
Default Value:
Access:
0CFCh
00000000h
Read/Write
32 bits
Size:
CONFIG_DATA is a 32-bit Read/Write window into Configuration Space. The portion of
Configuration Space that is referenced by CONFIG_DATA is determined by the contents of
CONFIG_ADDRESS.
Figure 3.
Configuration Data Register
31
0
Bit
0
Default
Configuration Data Window
Bit
31:0
Descriptions
Configuration Data Window (CDW). If bit 31 of CONFIG_ADDRESS is 1, then any I/O access
to the CONFIG_DATA register will be mapped to Configuration Space using the contents of
CONFIG_ADDRESS.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
4.7
VGA I/O Mapped Registers
If Native Graphics mode is strapped, and Device #2 is enabled, and Function #0 within Device #2
is enabled for VGA, and IO_EN is set within Function #0 then GMCH claims a set of I/O registers
that are Index – Data registers that are used to access Internal VGA registers.
Table 17.
VGA I/O Mapped Register List
Name
Function
Read @
Write @
ST00
ST01
FCR
MSR
VGA Input Status Register 0
3C2h
3BAh/3Dah
3CAh
–
–
VGA Input Status Register 1
VGA Feature Control Register
VGA Miscellaneous Status/Output Register
3BAh/3DAh
3C2h
3CCh
Table 18.
Index – Data Registers
Name
Function
Index IO
Data IO
SRX
GRX
ARX
Sequencer Registers
3C4
3CE
3C0
3C5
3CF
Graphics Controller Registers
Attribute Control Registers
3C0: Write
3C1: Read
DACMASK
DACSTATE
DACRX
Pixel Data Mask Register
DAC State Register
--
--
3C6h
3C7 Read Only
--
Palette Read Index Register
Palette Write Index Register
Palette Data Register
CRT Registers
3C7 Write Only
3C8 Write Only
3C9
DACWX
DACDATA
CRX
3B4/3D4
3B5/3D5
(MDA/CGA)
(MDA/CGA)
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Register Description
4.8
Intel 854 GMCH Host-Hub Interface Bridge Device Registers
(Device #0, Function #0)
Table 5 summarizes the configuration space for Device #0, Function#0.
Table 19.
GMCH Configuration Space - Device #0, Function#0
Register
Symbol
Register
Start
Register
End
Register Name
Default Value
Access
Vendor Identification
Device Identification
PCI Command
VID
DID
00
02
04
06
08
0A
0B
0E
2C
01
03
05
07
08
0A
0B
0E
2D
8086h
358Ch
0006h
0090h
02h
RO
RO
PCICMD
PCISTS
RID
RO,R/W
RO,R/WC
RO
PCI Status
Revision Identification
Sub-Class Code
Base Class Code
Header Type
SUBC
BCC
00h
RO
06h
RO
HDR
80h
RO
Subsystem Vendor
Identification
SVID
0000h
R/WO
Subsystem Identification
Capabilities Pointer
SID
CAPPTR
CAPID
GMC
2E
34
40
50
52
54
58
59
60
2F
34
44
51
53
55
58
5F
60
0000h
40h
R/WO
RO
Capability Identification
GMCH Misc. Control
84_A105_0009h
0000h
RO
R/W
R/W
R/W
R/W
R/W
R/W/L
GMCH Graphics Control
Device and Function Control
Fixed Dram Hole Control
Programmable Attribute Map
GGC
0030h
DAFC
0000h
FDHC
00h
PAM (6:0)
SMRAM
00h Each
02h
System Management RAM
Control
Extended System
ESMRAMC
61
61
38h
R/W/L
Management RAM Control
Error Status
ERRSTS
ERRCMD
SMICMD
SCICMD
SHIC
62
64
66
67
74
63
65
66
67
77
0000h
0000h
00h
R/WC
R/W
Error Command
SMI Command
SCI Command
R/W
00h
R/W
Secondary Host Interface
Control Register
00006010h
RO, R/W
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
Aperture Translation Table
Base
ATTBASE
HEM
B8
F0
BB
F3
00000000h
00000000h
RO, R/W
RO, R/W
Host Error Control/Status/
Obs
50
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Register Description
4.8.1
VID – Vendor Identification Register
Address Offset:
Default Value:
Access:
00-01h
8086h
Read only
16 bits
Size:
The VID Register contains the vendor identification number. This 16-bit register, combined with
the Device Identification Register, uniquely identifies any PCI device. Writes to this register have
no effect.
Bit
Descriptions
15:0
Vendor Identification (VID): This register field contains the PCI standard identification for Intel.
4.8.2
DID – Device Identification Register
Address Offset:
Default Value:
Access:
02-03h
358Ch
Read only
16 bits
Size:
This 16-bit register combined with the Vendor Identification register uniquely identifies any PCI
device. Writes to this register have no effect.
Bit
Descriptions
15:0
Device Identification (DID): This is a 16-bit value assigned to the GMCH Host-Hub interface
bridge, Device #0.
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
4.8.3
PCICMD – PCI Command Register
Address Offset:
Default Value:
Access:
04-05h
0006h
Read only, Read/Write
16 bits
Size:
Since GMCH Device #0 does not physically reside on PCI_A many of the bits are not
implemented.
Bit
Descriptions
Reserved
15:10
9
Fast Back-to-Back Enable (FB2B): This bit controls whether or not the master can do fast back-
to-back Write. Since Device #0 is strictly a target, this bit is not implemented and is hardwired to
0. Writes to this bit position have no affect.
8
SERR Enable (SERRE): This bit is a global enable bit for Device #0 SERR messaging. The
GMCH does not have an SERR# signal, but communicates the SERR# condition by sending an
SERR message to the ICH4-M.
1 = Enable. GMCH is enabled to generate SERR messages over Hub interface for specific
Device #0 error conditions that are individually enabled in the ERRCMD register. The error status
is reported in the ERRSTS and PCISTS registers.
0 = SERR message is not generated by the GMCH for Device #0.
NOTE: This bit only controls SERR messaging for the Device #0. Device #1 has its own SERRE
bit to control error reporting for error conditions occurring on Device #1. The two control bits are
used in a logical OR manner to enable the SERR Hub interface message mechanism.
7
6
5
4
Address/Data Stepping Enable (ADSTEP): Address/data stepping is not implemented in the
GMCH, and this bit is hardwired to 0. Writes to this bit position have no effect.
Parity Error Enable (PERRE): PERR# is not implemented by GMCH and this bit is hardwired to
0. Writes to this bit position have no effect.
VGA Palette Snoop Enable (VGASNOOP): The GMCH does not implement this bit and it is
hardwired to a 0. Writes to this bit position have no effect.
Memory Write and Invalidate Enable (MWIE): The GMCH will never issue memory write and
invalidate commands. This bit is therefore hardwired to 0. Writes to this bit position will have no
effect.
3
2
1
0
Special Cycle Enable (SCE): The GMCH does not implement this bit and it is hardwired to a 0.
Writes to this bit position have no effect.
Bus Master Enable (BME): The GMCH is always enabled as a master on HI. This bit is
hardwired to a 1. Writes to this bit position have no effect.
Memory Access Enable (MAE): The GMCH always allows access to main system memory. This
bit is not implemented and is hardwired to 1. Writes to this bit position have no effect.
I/O Access Enable (IOAE): This bit is not implemented in the GMCH and is hardwired to a 0.
Writes to this bit position have no effect.
52
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Register Description
4.8.4
PCI Status Register
Address Offset:
Default Value:
Access:
06-07h
0090h
Read only, Read/WriteClear
16 bits
Size:
PCISTS is a 16-bit status register that reports the occurrence of error events on Device #0's PCI
Interface. Bit 14 is Read/Write Clear. All other bits are Read Only. Since GMCH Device #0 does
not physically reside on PCI_A many of the bits are not implemented.
Bit
Descriptions
15
Detected Parity Error (DPE): The GMCH does not implement this bit and it is hardwired to a 0.
Writes to this bit position have no effect.
14
Signaled System Error (SSE): R/WC. This bit is set to 1 when GMCH Device #0 generates an
SERR message over HI for any enabled Device #0 error condition. Device #0 error conditions are
enabled in the PCICMD and ERRCMD registers. Device #0 error flags are read/reset from the
PCISTS or ERRSTS registers. Software sets SSE to 0 by writing a 1 to this bit.
13
12
Received Master Abort Status (RMAS): R/WC. This bit is set when the GMCH generates a HI
request that receives a Master Abort completion packet or Master Abort Special Cycle. Software
clears this bit by writing a 1 to it.
Received Target Abort Status (RTAS): R/WC. This bit is set when the GMCH generates a HI
request that receives a Target Abort completion packet or Target Abort Special Cycle. Software
clears this bit by writing a 1 to it. If bit 6 in the ERRCMD is set to a one and an Serr# special cycle
is generated on the HI bus.
11
Signaled Target Abort Status (STAS): The GMCH will not generate a Target Abort HI
completion packet or Special Cycle. This bit is not implemented in the GMCH and is hardwired to
a 0. Writes to this bit position have no effect.
10:9
DEVSEL Timing (DEVT): These bits are hardwired to “00”. Writes to these bit positions have no
affect. Device #0 does not physically connect to PCI_A. These bits are set to “00” (fast decode)
so that the GMCH does not limit optimum DEVSEL timing for PCI_A.
8
7
Master Data Parity Error Detected (DPD): PERR signaling and messaging are not implemented
by the GMCH therefore this bit is hardwired to 0. Writes to this bit position have no effect.
Fast Back-to-Back (FB2B): This bit is hardwired to 1. Writes to these bit positions have no
effect. Device #0 does not physically connect to PCI_A. This bit is set to 1 (indicating fast back-to-
back capability) so that the GMCH does not limit the optimum setting for PCI_A.
6:5
4
Reserved
Capability List (CLIST): This bit is hardwired to 1 to indicate to the configuration software that
this device/function implements a list of new capabilities. A list of new capabilities is accessed via
register CAPPTR at configuration address offset 34h.
3:0
Reserved
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Intel 82854 Graphics Memory Controller Hub (GMCH)
4.8.5
RID – Register Identification
Address Offset:
Default Value:
Access:
08h
02h
Read only
8 bits
Size:
This register contains the revision number of the GMCH Device #0. These bits are read only and
writes to this register have no effect.
Bit
Descriptions
7:0
Revision Identification Number (RID): This is an 8-bit value that indicates the revision
identification number for the GMCH Device #0.
4.8.6
SUBC – Sub Class Code Register
Address Offset:
Default Value:
Access:
0Ah
00h
Read only
8 bits
Size:
This register contains the Sub-Class Code for the GMCH Device #0. This code is 00h indicating a
Host Bridge device.
Bit
Descriptions
7:0
Sub-Class Code (SUBC): This is an 8-bit value that indicates the category of Bridge into which
the GMCH falls. The code is 00h indicating a Host Bridge.
54
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Register Description
4.8.7
BCC – Base Class Code Register
Address Offset:
Default Value:
Access:
0Bh
06h
Read only
8 bits
Size:
This register contains the Base Class code of the GMCH Device #0. This code is 06h indicating a
Bridge device.
Bit
Descriptions
7:0
Base Class Code (BASEC): This is an 8-bit value that indicates the Base Class Code for the
GMCH. This code has the value 06h, indicating a Bridge device.
4.8.8
HDR – Header Type Register
Address Offset:
Default Value:
Access:
0Eh
80h
Read only
8 bits
Size:
This register identifies the header layout of the configuration space. No physical register exists at
this location.
Bit
Descriptions
7:0
PCI Header (HDR): This field always returns 80 to indicate that Device #0 is a multifunction
device. If Functions other than 0 are disabled, this field returns a 00 to indicate that the GMCH is a
single function device with standard header layout. Writes to this location have no effect.
4.8.9
SVID – Subsystem Vendor Identification Register
Address Offset:
Default Value:
Access:
2C-2Dh
0000h
Read/Write Once
16 bits
Size:
This value is used to identify the vendor of the subsystem.
Bit
Descriptions
15:0
Subsystem Vendor ID (SUBVID): This field should be programmed during boot-up to indicate the
vendor of the system board. After it has been written once, it becomes Read Only.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
4.8.10
SID – Subsystem Identification Register
Address Offset:
Default Value:
Access:
2E-2Fh
0000h
Read/Write Once
16 bits
Size:
This value is used to identify a particular subsystem.
Bit
Descriptions
15:0
Subsystem ID (SUBID): This field should be programmed during BIOS initialization. After it has
been written once, it becomes Read Only.
4.8.11
CAPPTR – Capabilities Pointer Register
Address Offset:
Default Value:
Access:
34h
40h
Read Only
8 bits
Size:
The CAPPTR provides the offset that is the pointer to the location of the first device capability in
the capability list.
Bit
Descriptions
7:0
Pointer to the offset of the first capability ID register block: In this case the first capability is
the Product-Specific Capability, which is located at offset 40h.
56
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Register Description
4.8.12
CAPID – Capabilities Identification Register (Device #0)
Address Offset:
Default Value:
Access:
40-44h
chipset independent
Read Only
40 bits
Size:
The Capability Identification Register uniquely identifies chipset capabilities as defined in the
table below. The bits in this register are intended to define a capability ceiling for each feature, not
a capability select. The capability selection for each feature is implemented elsewhere. The
mechanism to select the capability for each feature must comprehend these Capability registers and
not allow a selected setting above the ceiling specified in these registers. The BIOS must read this
register to identify the part and comprehend the capabilities specified within when configuring the
effected portions of the GMCH.
The default setting, in most cases, allows the maximum capability. Exceptions are noted in the
individual bits. This register is Read Only. Writes to this register have no effect.
Bit
Descriptions
39:37
Capability ID [2:0]:
000: Intel® 82854 GMCH
001-111: Reserved
36:28
27:24
Reserved
CAPREG Version: This field has the value 0001b to identify the first revision of the CAPREG
definition.
23:16
15:0
Cap_length: This field has the value 05h indicating the structure length.
Reserved
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Intel 82854 Graphics Memory Controller Hub (GMCH)
4.8.13
GMC – GMCH Miscellaneous Control Register (Device #0)
Address Offset:
Default Value:
Access:
50-51h
0000h
Read/Write
16 bits
Size:
Bit
Descriptions
15:10
Reserved
Reserved
9
8
RRBAR Access Enable—R/W:
1: Enables the RRBAR space.
0: Disable
7:1
0
Reserved
MDA Present (MDAP)—R/W:
This bit should not be set when the VGA Enable bit is not set. If the VGA enable bit is set, then
accesses to IO address range x3BCh–x3BFh are forwarded to Hub interface. If the VGA enable bit
is not set then accesses to IO address range x3BCh–x3BFh are treated just like any other IO
accesses. MDA resources are defined as the following:
Memory: 0B0000h – 0B7FFFh
I/O: 3B4h, 3B5h, 3B8h, 3B9h, 3BAh, 3BFh,
(including ISA address aliases, A[15:10] are not used in decode)
Any I/O reference that includes the I/O locations listed above, or their aliases, will be forwarded to
Hub interface even if the reference includes I/O locations not listed above.
The following table shows the behavior for all combinations of MDA and VGA:
VGA
0 0
MDA Behavior
All References to MDA and VGA go to Hub interface (Default)
Reserved
0 1
1 0
All References to VGA go to PCI.
MDA-only references (I/O address 3BF and aliases will go to Hub interface.
1 1
VGA References go to PCI; MDA References go to Hub interface
58
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Register Description
4.8.14
GGC – GMCH Graphics Control Register (Device #0)
Address Offset:
Default Value:
Access:
52-53h
0030h
Read/Write
16 bits
Size:
Bit
Descriptions
Reserved
15:7
6:4
Graphics Mode Select (GMS): This field is used to select the amount of Main system memory
that is pre-allocated to support the Internal Graphics Device in VGA (non-linear) and Native (linear)
modes. The BIOS ensures that system memory is pre-allocated only when Internal Graphics is
enabled.
000: No system memory pre-allocated. Device #2 (IGD) does not claim VGA cycles (Memory and
I/O), and the Sub-Class Code field within Device #2 Function #0 Class Code register is 80.
001: DVMT (UMA) mode, 1 MB of system memory pre-allocated for frame buffer.
010: DVMT (UMA) mode, 4 MB of system memory pre-allocated for frame buffer.
011: DVMT (UMA) mode, 8 MB of system memory pre-allocated for frame buffer.
100: DVMT (UMA) mode, 16 MB of system memory pre-allocated for frame buffer.
101: DVMT (UMA) mode, 32 MB of system memory pre-allocated for frame buffer.
All other combinations reserved.
3
2
Reserved
Device #2 Function #1 Enable/Disable:
1: Disable Function #1 within Device #2.
0: Enable Function #1 within Device #2.
1
0
IGD VGA Disable (IVD): VGA can only be enabled in Naytive Graphics Mode. If strapped in other
mode, this bit should always set to 1.
1: Disable. Device #2 (IGD) does not claim VGA Memory and I/O Mem cycles, and the Sub-Class
Code field within Device #2 Function #0 Class Code register is 80.
0: Enable. Device #2 (IGD) claims VGA Memory and I/O cycles, the Sub-Class Code within Device
#2 Class Code register is 00.
Reserved
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
4.8.15
DAFC – Device and Function Control Register (Device #0)
Address Offset:
Default Value:
Access:
54-55h
0000h
Read/Write
16 bits
Size:
This 16-bit register controls the visibility of devices and functions within the GMCH to
configuration software.
Bit
Description
Reserved
15:8
7
Device #2 Disable:
1: Disabled.
0: Enabled.
6:3
2
Reserved
Device #0 Function #3 Disable:
1: Disable Function #3 registers within Device #0 and all associated DDR SDRAM and I/O ranges.
0: Enable Function #3 within Device #0.
1
0
Reserved
Device #0 Function #1 Disable:
1: Disable Function #1 within Device #0.
0: Enable Function #1 within Device #0.
4.8.16
FDHC – Fixed DRAM Hold Control Register (Device #0)
Address Offset:
Default Value:
Access:
58h
00h
Read/Write
8 bits
Size:
This 8-bit register controls a single fixed DDR SDRAM hole: 15-16 MB.
Bit
Description
7
Hole Enable (HEN): This field enables a memory hole in DDR SDRAM space. Host cycles
matching an enabled hole are passed onto ICH4-M through Hub interface. The GMCH will ignore
Hub interface cycles matching an enabled hole.
NOTE: A selected hole is not re-mapped.
0: None
1: 15 MB–16 MB (1MBs)
6:0
Reserved
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Register Description
4.8.17
PAM(6:0) – Programmable Attribute Map Register (Device #0)
Address Offset:
Default Value:
Access:
59-5Fh
00h Each
Read/Write
Size:
4 bits/register, 14 registers
The GMCH allows programmable DDR SDRAM attributes on 13 Legacy system memory
segments of various sizes in the 640 kB -1 MB address range. Seven Programmable Attribute Map
(PAM) registers are used to support these features. Cacheability of these areas is controlled via the
MTRR registers in the P6 processor. Two bits are used to specify system memory attributes for
each system memory segment. These bits apply to both Host and Hub interface initiator accesses to
the PAM areas. These attributes are:
• RE - Read Enable. When RE = 1, the CPU Read accesses to the corresponding system
memory segment are claimed by the GMCH and directed to main system memory. Conversely,
when RE = 0, the Host Read accesses are directed to PCI0.
• WE - Write Enable. When WE = 1, the Host Write accesses to the corresponding system
memory segment are claimed by the GMCH and directed to main system memory. Conversely,
when WE = 0, the Host Write accesses are directed to PCI0.
The RE and WE attributes permit a system memory segment to be Read Only, Write Only, Read/
Write, or Disabled. For example, if a system memory segment has RE = 1 and WE = 0, the segment
is Read Only.
Each PAM register controls two regions, typically 16 kB in size. Each of these regions has a 4-bit
field. The 4 bits that control each region have the same encoding and are defined in the following
table.
Table 20.
Attribute Bit Assignment
Bits [7, 3]
Reserved
Bits [6, 2]
Reserved
Bits [5, 1]
WE
Bits [4, 0]
RE
Description
X
X
0
0
Disabled. DDR SDRAM is disabled and all accesses
are directed to Hub interface. The GMCH does not
respond as a Hub interface target for any Read or
Write access to this area.
X
X
0
1
Read Only. Reads are forwarded to DDR SDRAM
and Writes are forwarded to Hub interface for
termination. This Write protects the corresponding
DDR SDRAM segment. The GMCH will respond as a
Hub interface target for Read accesses but not for
any Write accesses.
X
X
X
X
1
1
0
1
Write Only. Writes are forwarded to DDR SDRAM
and Reads are forwarded to the Hub interface for
termination. The GMCH will respond as a Hub
interface target for Write accesses but not for any
Read accesses.
Read/Write. This is the normal operating mode of
main system memory. Both Read and Write cycles
from the host are claimed by the GMCH and
forwarded to DDR SDRAM. The GMCH will respond
as a Hub interface target for both Read and Write
accesses.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
As an example, consider a BIOS that is implemented on the Expansion bus. During the
initialization process, the BIOS can be shadowed in main system memory to increase the system
performance. When BIOS is shadowed in main system memory, it should be copied to the same
address location. To shadow the BIOS, the attributes for that address range should be set to Write
Only. The BIOS is shadowed by first doing a Read of that address. This Read is forwarded to the
Expansion bus. The Host then does a Write of the same address, which is directed to main system
memory. After the BIOS is shadowed, the attributes for that system memory area are set to Read
registers and the associated attribute bits.
Figure 4.
PAM Registers
Offset
PAM6
PAM5
PAM4
PAM3
PAM2
PAM1
PAM0
5Fh
5Eh
5Dh
5Ch
5Bh
5Ah
59h
7
6
5
4
3
2
1
0
R
R
WE
RE
R
R
WE
RE
Reserved
Reserved
Read Enable (R/W)
1=Enable
0=Disable
Write Enable (R/W)
1=Enable
0=Disable
Write Enable (R/W)
1=Enable
0=Disable
Read Enable (R/W)
1=Enable
0=Disable
Reserved
Reserved
pam
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Register Description
Table 21.
PAM Registers and Associated System Memory Segments
PAM Reg
Attribute Bits
System Memory Segment
Reserved
Comments
Offset
PAM0[3:0]
59h
PAM0[7:4]
PAM1[3:0]
PAM1[7:4]
PAM2[3:0]
PAM2[7:4]
PAM3[3:0]
PAM3[7:4]
PAM4[3:0]
PAM4[7:4]
PAM5[3:0]
PAM5[7:4]
PAM6[3:0]
PAM6[7:4]
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
WE
RE
0F0000h–0FFFFFh
0C0000h–0C3FFFh
0C4000h–0C7FFFh
0C8000h–0CBFFFh
0CC000h–0CFFFFh
0D0000h–0D3FFFh
0D4000h–0D7FFFh
0D8000h–0DBFFFh
0DC000h–0DFFFFh
0E0000h–0E3FFFh
0E4000h–0E7FFFh
0E8000h–0EBFFFh
0EC000h–0EFFFFh
BIOS Area
59h
5Ah
5Ah
5Bh
5Bh
5Ch
5Ch
5Dh
5Dh
5Eh
5Eh
5Fh
5Fh
WE
WE
WE
WE
WE
WE
WE
WE
WE
WE
WE
WE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
ISA Add-on BIOS
ISA Add-on BIOS
ISA Add-on BIOS
ISA Add-on BIOS
ISA Add-on BIOS
ISA Add-on BIOS
ISA Add-on BIOS
ISA Add-on BIOS
BIOS Extension
BIOS Extension
BIOS Extension
BIOS Extension
For details on overall system address mapping scheme see the Address Decoding section of this
document.
DOS Application Area (00000h-9FFFh)
The DOS area is 640 kB in size and it is further divided into two parts. The 512-kB area at 0 to
7FFFFh is always mapped to the main system memory controlled by the GMCH, while the 128-kB
address range from 080000 to 09FFFFh can be mapped to PCI0 or to main DDR SDRAM. By
default this range is mapped to main system memory and can be declared as a main system
memory hole (accesses forwarded to PCI0) via GMCH's FDHC Configuration register.
Video Buffer Area (A0000h-BFFFFh)
Attribute Bits do not control this 128-kB area. The Host-initiated cycles in this region are always
forwarded to either PCI0 or PCI2 unless this range is accessed in SMM mode. Routing of accesses
is controlled by the Legacy VGA Control Mechanism of the "Virtual" PCI-PCI Bridge Device
embedded within the GMCH.
This area can be programmed as SMM area via the SMRAM register. When the GMCH is strapped
in other mode, or when used as an SMM space, this range can not be accessed from the Hub
interface.
Expansion Area (C0000h-DFFFFh)
This 128-kB area is divided into eight 16-kB segments that can be assigned with different attributes
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Intel 82854 Graphics Memory Controller Hub (GMCH)
Extended System BIOS Area (E0000h-EFFFFh)
This 64-kB area is divided into four 16-kB segments that can be assigned with different attributes
System BIOS Area (F0000h-FFFFFh)
This area is a single 64-kB segment that can be assigned with different attributes via PAM Control
4.8.18
SMRAM – System Management RAM Control Register (Device #0)
Address Offset:
Default Value:
Access:
60h
02h
Read/Write/Lock, Read Only
8 bits
Size:
The SMRAM register controls how accesses to Compatible and Extended SMRAM spaces are
treated. The Open, Close, and Lock Bits function only when G_SMRAME Bit is set to a 1. Also,
the Open Bit must be Reset before the LOCK Bit is set.
Bit
Description
Reserved
7
6
SMM Space Open (D_OPEN): When D_OPEN=1 and D_LCK=0, the SMM space DDR
SDRAM is made visible even when SMM decode is not active. This is intended to help BIOS
initialize SMM space. Software should ensure that D_OPEN=1 and D_CLS=1 are not set at the
same time. When D_LCK is set to a 1, D_OPEN is Reset to 0 and becomes Read Only.
5
4
SMM Space Closed (D_CLS): When D_CLS = 1 SMM Space, DDR SDRAM is not accessible
to data references, even if SMM decode is active. Code references may still access SMM
space DDR SDRAM. This will allow SMM software to reference “through” SMM space to
update the display even when SMM is mapped over the VGA range. Software should ensure
that D_OPEN=1 and D_CLS=1 are not set at the same time. D_CLS applies to all SMM spaces
(Cseg, Hseg, and Tseg).
SMM Space Locked (D_LCK): When D_LCK is set to 1, then D_OPEN is Reset to 0 and
D_LCK, D_OPEN, G_SMRAME, C_BASE_SEG, GMS, DRB, DRA, H_SMRAM_EN, TSEG_SZ
and TSEG_EN become Read Only. D_LCK can be set to 1 via a normal Configuration Space
Write but can only be cleared by a Full Reset. The combination of D_LCK and D_OPEN
provide convenience with security. The BIOS can use the D_OPEN function to initialize SMM
space and then use D_LCK to “lock down” SMM space in the future so that no application
software (or BIOS itself) can violate the integrity of SMM space, even if the program has
knowledge of the D_OPEN function.
3
Global SMRAM Enable (G_SMRAME): If set to a 1, then Compatible SMRAM functions is
enabled, providing 128 kB of DDR SDRAM accessible at the A0000h address while in SMM
(ADS# with SMM decode). To enable Extended SMRAM function this bit must be set to 1, refer
to the section on SMM for more details. Once D_LCK is set, this bit becomes Read Only.
2:0
Compatible SMM Space Base Segment (C_BASE_SEG)—RO: This field indicates the
location of SMM space. “SMM DRAM” is not remapped. It is simply “made visible” if the
conditions are right to access SMM space, otherwise the access is forwarded to Hub interface.
C_BASE_SEG is hardwired to 010 to indicate that the GMCH supports the SMM space at
A0000h–BFFFFh.
64
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Register Description
4.8.19
ESMRAMC – Extended System Management RAM Control (Device #0)
Address Offset:
Default Value:
Access:
61h
38h
Read/Write/Lock
8 bits
Size:
The Extended SMRAM register controls the configuration of Extended SMRAM Space. The
Extended SMRAM (E_SMRAM) Memory provides a Write-Back cacheable SMRAM Memory
Space that is above 1 MB.
Bit
Description
7
H_SMRAM_EN (H_SMRAME): Controls the SMM Memory Space location (that is, above 1 MB
or below 1 MB). When G_SMRAME is 1 and H_SMRAME this bit is set to 1, the high SMRAM
Memory Space is enabled. SMRAM accesses from 0FEDA0000h to 0FEDBFFFFh are
remapped to DDR SDRAM address 000A0000h to 000BFFFFh.
Once D_LCK is set, this bit becomes Read Only.
6
E_SMRAM_ERR (E_SMERR): This bit is set when CPU accesses the defined DDR SDRAM
ranges in Extended SMRAM (High system memory and T-segment) while not in SMM Space. It
is software’s responsibility to clear this bit. The software must Write a 1 to this bit to clear it.
5
SMRAM_Cache (SM_CACHE): GMCH forces this bit to 1.
SMRAM_L1_EN (SM_L1): GMCH forces this bit to 1.
SMRAM_L2_EN (SM_L2): GMCH forces this bit to 1.
Reserved
4
3
2:1
0
TSEG_EN (T_EN): Enabling of SMRAM Memory (TSEG, 1 Mbytes of additional SMRAM
Memory) for Extended SMRAM Space only. When G_SMRAME =1 and TSEG_EN = 1, the
TSEG is enabled to appear in the appropriate physical address space.
Once D_LCK is set, this bit becomes Read Only.
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
4.8.20
ERRSTS – Error Status Register (Device #0)
Address Offset:
Default Value:
Access:
62-63h
0000h
Read/Write Clear
16 bits
Size:
This register is used to report various error conditions via Hub Interface Special cycles. An SERR,
SMI, or SCI Error Hub Interface Special cycle may be generated on a zero to one transition of any
of these flags when enabled in the PCICMD/ERRCMD, SMICMD, or SCICMD registers
respectively.
Bit
Description
Reserved
15:14
13
FSB Strobe Glitch Detected (FSBAGL): When this bit is set to 1 the GMCH has detected a glitch
on one of the FSB strobes. Writing a 1 to it clears this bit.
12
11
GMCH Software Generated Event for SMI:
1: This indicates the source of the SMI was a Device #2 Software Event.
0: Software must Write a 1 to clear this bit.
GMCH Thermal Sensor Event for SMI/SCI/SERR:
1: Indicates that a GMCH Thermal Sensor trip has occurred and an SMI, SCI or SERR has been
generated. Note that the status bit is set only if a message is sent based on Thermal event
enables in Error Command, SMI Command and SCI Command registers. Note that a Trip Point
can generate one of SMI, SCI or SERR interrupts (two or more per event is illegal). Multiple Trip
Points can generate the same interrupt. If software chooses this mode, then subsequent Trips
may be lost.
0: Software must Write a 1 to clear this status bit. If this bit is set, then an interrupt message will not
be sent on a new Thermal Sensor event.
10
9
Reserved
LOCK to non-DDR SDRAM Memory Flag (LCKF)—R/WC:
1: Indicates that a CPU initiated LOCK cycle targeting non-DDR SDRAM Memory Space occurred.
0: Software must Write a 1 to clear this status bit
8
7
Received Refresh Timeout—R/WC:
1: This bit is set when 1024 memory core refresh are Queued up.
0: Software must Write a 1 to clear this status bit.
DRAM Throttle Flag (DTF)—R/WC:
1: Indicates that the DDR SDRAM Throttling condition occurred.
0: Software must Write a 1 to clear this status bit.
6
5
Reserved
Received Unimplemented Special Cycle Hub Interface Completion Packet FLAG (UNSC)—
R/WC:
1: Indicates that the GMCH initiated a Hub interface request that was terminated with an
Unimplemented Special Cycle completion packet.
0: Software must Write a 1 to clear this status bit.
4:0
Reserved
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Register Description
4.8.21
ERRCMD – Error Command Register (Device #0)
Address Offset:
Default Value:
Access:
64-65h
0000h
Read/Write Clear
16 bits
Size:
This register enables various errors to generate a SERR Hub Interface Special cycle. Since the
GMCH does not have a SERR# signal, SERR messages are passed from the GMCH to the ICH4-M
over Hub interface. The actual generation of the SERR message is globally enabled for Device
#0 via the PCI Command register.
Note: An error can generate one and only one Hub Interface Error Special cycle. It is software's
responsibility to make sure that when an SERR error message is enabled for an error condition,
SMI and SCI error messages are disabled for that same error condition.
Bit
Description
Reserved
15:14
13
SERR on FSB Strobe Glitch: When this bit is asserted, the GMCH will generate a HI SERR
message when a glitch is detected on one of the FSB strobes.
12
11
Reserved
SERR on GMCH Thermal Sensor Event:
1: The GMCH generates a SERR Hub Interface Special cycle on a Thermal Sensor Trip that
requires an SERR. The SERR must not be enabled at the same time as the SMI/SCI for a
Thermal Sensor Trip event.
0: Software must write a 1 to clear this status bit.
10
9
Reserved
SERR on LOCK to non-DDR SDRAM Memory:
1: The GMCH generates an SERR Hub Interface Special cycle when a CPU initiated LOCK
transaction targeting non-DDR SDRAM Memory Space occurs.
0: Reporting of this condition is disabled.
8
7
6
SERR on DDR SDRAM Refresh timeout:
1: The GMCH generates an SERR Hub Interface Special cycle when a DDR SDRAM Refresh
timeout occurs.
0: Reporting of this condition is disabled.
SERR on DDR SDRAM Throttle Condition:
1: The GMCH generates an SERR Hub Interface Special cycle when a DDR SDRAM Read or
Write Throttle condition occurs.
0: Reporting of this condition is disabled.
SERR on Receiving Target Abort on Hub Interface:
1: The GMCH generates an SERR Hub Interface Special cycle when a GMCH originated Hub
interface cycle is terminated with a Target Abort.
0: Reporting of this condition is disabled.
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
5
SERR on Receiving Unimplemented Special Cycle Hub Interface Completion Packet:
1: The GMCH generates an SERR Hub Interface Special cycle when a GMCH initiated Hub
interface request is terminated with a Unimplemented Special cycle completion packet.
0: Reporting of this condition is disabled.
4:2
1
Reserved
SERR on Multiple-bit ECC Error:
0: This system does not support ECC, this field must be set to 0.
0
SERR on Single-bit ECC Error:
0: This system does not support ECC, this field must be set to 0.
4.8.22
SMICMD – SMI Error Command Register (Device #0)
Address Offset:
Default Value:
Access:
66h
00h
Read/Write
8 bits
Size:
This register enables various errors to generate an SMI Hub Interface Special cycle. When an Error
Flag is set in the ERRSTS register, it can generate a SERR, SMI, or SCI Hub Interface Special
cycle when enabled in the ERRCMD, SMICMD, or SCICMD registers respectively.
Note: An error can generate one and only one Hub Interface Error Special cycle. It is software's
responsibility to make sure that when an SMI Error Message is enabled for an error condition,
SERR, and SCI Error Messages are disabled for that same error condition.
Bit
Description
7:4
3
Reserved
SMI on GMCH Thermal Sensor Trip:
1: An SMI Hub Interface Special cycle is generated by GMCH when the Thermal Sensor Trip
requires an SMI. A Thermal Sensor Trip Point cannot generate more than one special cycle.
2
1
Reserved
SMI on Multiple-bit ECC Error:
0: This system does not support ECC, this field must be set to 0.
0
SMI on Single-bit ECC Error:
0: This system does not support ECC, this field must be set to 0.
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Register Description
4.8.23
SCICMD – SCI Error Command Register (Device #0)
Address Offset:
Default Value:
Access:
67h
00h
Read/Write
8 bits
Size:
This register enables various errors to generate a SCI Hub Interface Special cycle. When an Error
Flag is set in the ERRSTS register, it can generate a SERR, SMI, or SCI Hub Interface Special
cycle when enabled in the ERRCMD, SMICMD, or SCICMD registers respectively.
Note: An error can generate one and only one Hub Interface Error Special cycle. It is software's
responsibility to make sure that when an SCI error message is enabled for an error condition, SERR
and SMI Error Messages are disabled for that same error condition.
Bit
Description
7:4
3
Reserved
SCI on GMCH Thermal Sensor Trip:
1: An SCI Hub Interface Special cycle is generated by GMCH when the Thermal Sensor Trip
requires an SCI. A Thermal Sensor Trip Point cannot generate more than one special cycle.
2
1
Reserved
SCI on Multiple-bit ECC Error:
0: This system does not support ECC, this field must be set to 0.
0
SCI on Single-bit ECC Error:
0: This system does not support ECC, this field must be set to 0.
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
4.8.24
SHIC – Secondary Host Interface Control Register (Device #0)
Address Offset:
Default Value:
Access:
74-77h
00006010h
Read Only, Read/Write
32 bits
Size:
Bit
Descriptions
Reserved
31
30
BREQ0# Control of FSB Address and Control bus power management:
0: Disable FSB address and control bus power management.
1: Eisable FSB address and control bus power management.
29:28
27
Reserved
On Die Termination (ODT) Gating Disable:
0: Enable.
1: Disable.
26:7
6
Reserved
FSB Data Bus Power Management Control:
0: FSB Data Bus Power Management disabled (Default).
1: FSB Data Bus Power Management enabled
5
Reserved
4:3
DPWR# Control.
00: DPWR# pin is always asserted.
10: DPWR# pin is asserted at least 2 clocks before read data is returned to the processor on the
FSB (2 clocks before DRDY# asserted). This is default setting.
01: DPWR# is always de-asserted.
11: Reserved
2
C2 state GMCH FSB Interface Power Management Control:
0: Power Management Disabled in C2 state
1: Power Management Enabled in C2 state
1
0
Reserved.
Reserved
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Register Description
4.8.25
HEM – Host Error Control, Status, and Observation (Device #0)
Address Offset:
Default Value:
Access:
F0-F3h
00000000h
Read Only, Read/Write
32 bits
Size:
Bit
Description
31
Detected HADSTB1# Glitch (ASTB1GL): This bit is set when the GMCH has detected a glitch
on address strobe HADSTB1#. Software must write a 1 to clear this status bit.
30
29
28
27
Detected HADSTB0# Glitch (ASTB0GL): This bit is set when the GMCH has detected a glitch
on address strobe HADSTB0#. Software must write a 1 to clear this status bit.
Detected HDSTB3# Glitch (DSTB3GL): This bit is set when the GMCH has detected a glitch on
data strobe pair HDSTB3#. Software must write a 1 to clear this status bit.
Detected HDSTB2# Glitch (DSTB2GL): This bit is set when the GMCH has detected a glitch on
data strobe pair HDSTB2#. Software must write a 1 to clear this status bit.
Detected HDSTB1# Glitch (DSTB1GL): This bit is set when the GMCH has detected a glitch on
data strobe pair HDSTB1#. Software must write a 1 to clear this status bit.
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
4.9
Intel 854 GMCH Main Memory Control, Memory I/O Control
Registers (Device #0, Function #1)
The following table shows the GMCH Configuration Space for Device #0, Function #1. See
“Nomenclature for Access Attributes” on page 42 for access nomenclature.
Table 22.
Host-Hub I/F Bridge/System Memory Controller Configuration Space (Device #0,
Function#1)
Register
Symbol
Register
Start
Register
End
Register Name
Default Value
Access
Vendor Identification
Device Identification
PCI Command
VID
DID
00
02
04
06
08
0A
0B
0E
2C
01
03
05
07
08
0A
0B
0E
2D
8086h
358Ch
0006h
0080h
02h
RO
RO
PCICMD
PCISTS
RID
RO,R/W
RO,R/WC
RO
PCI Status
Revision Identification
Sub-Class Code
Base Class Code
Header Type
SUBC
BCC
80h
RO
08h
RO
HDR
80h
RO
Subsystem Vendor
Identification
SVID
0000h
R/WO
Subsystem Identification
Capabilities Pointer
SID
CAPPTR
DRB
2E
34
40
50
60
68
2F
34
43
51
63
6B
0000h
00h
R/WO
RO
DRAM Row 0-3 Boundary
DRAM Row 0-3 Attribute
DRAM Timing
00000000h
7777h
RW
DRA
RW
DRT
18004425h
00000000h
RW
DRAM Controller Power
Management Control
PWRMG
R/W
Dram Controller Mode
DRAM Throttle Control
DRC
DTC
70
A0
73
A3
00000081h
00000000h
R/W
R/W/L
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Register Description
4.9.1
VID – Vendor Identification Register
Address Offset:
Default Value:
Access:
00-01h
8086h
Read Only
16 bits
Size:
The VID Register contains the vendor identification number. This 16-bit register combined with
the Device Identification Register uniquely identifies any PCI device. Writes to this register have
no effect.
Bit
Descriptions
15:0
Vendor Identification (VID): This register field contains the PCI standard identification for Intel.
4.9.2
DID – Device Identification Register
Address Offset:
Default Value:
Access:
02-03h
358Ch
Read Only
16 bits
Size:
This 16-bit register combined with the Vendor Identification register uniquely identifies any PCI
device. Writes to this register have no effect.
Bit
Descriptions
15:0
Device Identification Number (DID): This is a 16-bit value assigned to the GMCH Host- HI
Bridge Function #1 (358Ch).
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Intel 82854 Graphics Memory Controller Hub (GMCH)
4.9.3
PCICMD – PCI Command Register
Address Offset:
Default Value:
Access:
04-05h
0006h
Read Only, Read/Write
16 bits
Size:
Since Intel chipset Device #0 does not physically reside on PCI_A, many of the bits are not
implemented.
Bit
Descriptions
Reserved
15:10
9
Fast Back-to-Back Enable (FB2B): This bit controls whether or not the master can do fast back-
to-back Write. Since Device #0 is strictly a target, this bit is not implemented and is hardwired to
0. Writes to this bit position have no affect.
8
7
6
5
4
SERR Enable (SERRE): SERR# is not implemented by Function #1 of Device #0 of the GMCH
and this bit is hardwired to 0. Writes to this bit position have no effect.
Address/Data Stepping Enable (ADSTEP): Address/data stepping is not implemented in the
GMCH, and this bit is hardwired to 0. Writes to this bit position have no effect.
Parity Error Enable (PERRE): PERR# is not implemented by GMCH and this bit is hardwired to
0. Writes to this bit position have no effect.
VGA Palette Snoop Enable (VGASNOOP): The GMCH does not implement this bit and it is
hardwired to a 0. Writes to this bit position have no effect.
Memory Write and Invalidate Enable (MWIE): The GMCH will never issue Memory Write and
Invalidate commands. This bit is therefore hardwired to 0. Writes to this bit position will have no
effect.
3
2
1
0
Special Cycle Enable (SCE): The GMCH does not implement this bit and it is hardwired to a 0.
Writes to this bit position have no effect.
Bus Master Enable (BME): The GMCH is always enabled as a master on HI. This bit is
hardwired to a 1. Writes to this bit position have no effect.
Memory Access Enable (MAE): The GMCH always allows access to main system memory. This
bit is not implemented and is hardwired to 1. Writes to this bit position have no effect.
I/O Access Enable (IOAE): This bit is not implemented in the GMCH and is hardwired to a 0.
Writes to this bit position have no effect.
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Register Description
4.9.4
PCISTS – PCI Status Register
Address Offset:
Default Value:
Access:
06-07h
0080h
Read Only, Read/Write Clear
16 bits
Size:
PCISTS is a 16-bit status register that reports the occurrence of error events on Device #0's PCI
Interface. Bit 14 is Read/Write Clear. All other bits are Read Only. Since GMCH Device #0 does
not physically reside on PCI_A, many of the bits are not implemented.
Bit
Descriptions
15
Detected Parity Error (DPE): The GMCH does not implement this bit and it is hardwired to a 0.
Writes to this bit position have no effect.
14
Signaled System Error (SSE): The GMCH does not implement this bit and it is hardwired to a 0.
Writes to this bit position have no effect.
13
Received Master Abort Status (RMAS): The GMCH does not implement this bit and it is
hardwired to a 0. Writes to this bit position have no effect.
12
Received Target Abort Status (RTAS): The GMCH does not implement this bit and it is
hardwired to a 0. Writes to this bit position have no effect.
11
Signaled Target Abort Status (STAS): The GMCH does not implement this bit and it is
hardwired to a 0. Writes to this bit position have no effect.
10:9
DEVSEL Timing (DEVT): These bits are hardwired to “00”. Writes to these bit positions have no
affect. Device #0 does not physically connect to PCI_A. These bits are set to “00” (fast decode)
so that the GMCH does not limit optimum DEVSEL timing for PCI_A.
8
7
Master Data Parity Error Detected (DPD): The GMCH does not implement this bit and it is
hardwired to a 0. Writes to this bit position have no effect.
Fast Back-to-Back (FB2B): This bit is hardwired to 1. Writes to these bit positions have no
effect. Device #0 does not physically connect to PCI_A. This bit is set to 1 (indicating fast back-to-
back capability) so that the GMCH does not limit the optimum setting for PCI_A.
6:5
4
Reserved
Capability List (CLIST): This bit is hardwired to 0 to indicate to the configuration software that
this device/function does not implement new capabilities.
Default Value = 0
3:0
Reserved
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Intel 82854 Graphics Memory Controller Hub (GMCH)
4.9.5
4.9.6
4.9.7
RID – Revision Identification Register
Address Offset:
Default Value:
Access:
08h
02h
Read Only
8 bits
Size:
®
This register contains the revision number of the Intel 82854 GMCH Device #0. These bits are
Read Only and Writes to this register have no effect.
Bit
Descriptions
7:0
Revision Identification Number (RID): This is an 8-bit value that indicates the revision
identification number for the GMCH Device #0.
RID – Revision Identification Register
Address Offset:
Default Value:
Access:
0Ah
80h
Read Only
8 bits
Size:
®
This register contains the Sub-Class code for the Intel 82854 GMCH Device #0. This code is 80h
indicating Other Peripheral device.
Bit
Descriptions
7:0
Sub-Class Code (SUBC): This is an 8-bit value that indicates the category of Peripheral device
into which the GMCH Function #1 falls. The code is 80h indicating Other Peripheral device.
BCC – Base Class Code Register
Address Offset:
Default Value:
Access:
0Bh
08h
Read Only
8 bits
Size:
®
This register contains the Base Class code of the Intel 82854 GMCH Device #0 Function #1. This
code is 08h indicating Other Peripheral device.
Bit
Descriptions
7:0
Base Class Code (BASEC): This is an 8-bit value that indicates the Base Class Code for the
GMCH. This code has the value 08h, indicating Other Peripheral device.
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Register Description
4.9.8
HDR – Header Type Register
Address Offset:
Default Value:
Access:
0Eh
80h
Read Only
8 bits
Size:
This register identifies the header layout of the configuration space. No physical register exists at
this location.
Bit
Descriptions
7:0
PCI Header (HDR): This field always returns 80 to indicate that Device #0 is a multifunction
device. Reads and Writes to this location have no effect.
4.9.9
SVID – Subsystem Vendor Identification Register
Address Offset:
Default Value:
Access:
2C-2Dh
0000h
Read/Write Once
16 bits
Size:
This value is used to identify the vendor of the subsystem.
Bit
Descriptions
15:0
Subsystem Vendor ID (SUBVID): This field should be programmed during boot-up to indicate
the vendor of the system board. After it has been written once, it becomes Read Only.
4.9.10
SID – Subsystem Identification Register
Address Offset:
Default Value:
Access:
2E-2Fh
0000h
Read/Write Once
16 bits
Size:
This value is used to identify a particular subsystem.
Bit
Descriptions
15:0
Subsystem ID (SUBID): This field should be programmed during BIOS initialization. After it has
been Written once, it becomes Read Only.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
4.9.11
CAPPTR – Capabilities Pointer Register
Address Offset:
Default Value:
Access:
34h
00h
Read Only
8 bits
Size:
The CAPPTR provides the offset that is the pointer to the location of the first device capability in
the capability list.
Bit
Descriptions
7:0
Pointer to the offset of the first capability ID register block: In this case there are no
capabilities, therefore these bits are hardwired to 00h to indicate the end of the capability linked
list.
4.9.12
DRB – DRAM Row (0:3) Boundary Register (Device #0)
Address Offset:
Default Value:
Access:
40-43h
00h each
Read/Write
8 bits each
Size:
The DDR SDRAM Row Boundary Register defines the upper boundary address of each DDR
SDRAM row with a granularity of 32 MB. Each row has its own single-byte DRB register. For
example, a value of 1 in DRB0 indicates that 32 MB of DDR SDRAM has been populated in the
first row. Since the GMCH supports a total of four rows of system memory, DRB0-3 are used. The
registers from 44h-4Fh are Reserved for DRBs 4-15.
Row0: 40h
Row1: 41h
Row2: 42h
Row3: 43h
44h to 4Fh is reserved.
DRB0 = Total system memory in Row0 (in 32-MB increments)
DRB1 = Total system memory in Row0 + Row1 (in 32-MB increments)
DRB2 = Total system memory in Row0 + Row1 + Row2 (in 32-MB increments)
DRB3 = Total system memory in Row0 + Row1 + Row2 + Row3 (in 32-MB increments)
Each Row is represented by a Byte. Each Byte has the following format.
Bit
Descriptions
7:0
DDR SDRAM Row Boundary Address: This 8-bit value defines the upper and lower addresses
for each DDR SDRAM row. This 8-bit value is compared against a set of address lines to
determine the upper address limit of a particular row. Also the minimum system memory
supported is 64 MB in 64-Mb granularity; hence bit 0 of this register must be programmed to a
zero.
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Register Description
4.9.13
DRA – DRAM Row Attribute Register (Device #0)
Address Offset:
Default Value:
Access:
50-51h
77h
Read/Write
8 bits
Size:
The DDR SDRAM Row Attribute Register defines the page sizes to be used when accessing
different pairs of Rows. Each Nibble of information in the DRA registers describes the page size
of a pair of Rows:
Row 0, 1:
Row 2, 3:
52h-5Fh:
50h
51h
Reserved.
7
6
4
4
3
2
0
0
R
Row attribute for Row1
R
Row Attribute for Row0
7
6
3
2
R
Row attribute for Row3
R
Row Attribute for Row2
Bit
Description
7
Reserved
6:4
Row Attribute for odd-numbered Row: This field defines the page size of the corresponding row.
000: Reserved
001: 4 kB
010: 8 kB
011: 16 kB
111: Not Populated
Others: Reserved
3
Reserved
2:0
Row Attribute for even-numbered Row: This field defines the page size of the corresponding row.
000: Reserved
001: 4 kB
010: 16 kB
111: Not Populated
Others: Reserved
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Intel 82854 Graphics Memory Controller Hub (GMCH)
4.9.14
DRT – DRAM Timing Register (Device #0)
Address Offset:
Default Value:
Access:
60-63h
18004425h
Read/Write
32 bits
Size:
This register controls the timing of the DDR SDRAM controller.
Bit
Description
31
DDR Internal Write to Read Command delay (tWTR):
The tWTR is a std. DDR SDRAM timing parameter with a value of 1 CK for CL=2 and 2.5. The
tWTR is used to time RD command after a WR command (to same Row):
0: tWTR is set to 1 Clock (CK), used for DDR SDRAM CL=2 or 2.5
1: Reserved
30
DDR Write Recovery time (tWR):
Write recovery time is a std. DDR timing parameter with the value of 15 ns. It should be set to 2 CK
when DDR200 is used. The tWR is used to time PRE command launch after a WR command,
when DDR SDRAM components are populated.
0: tWR is set to 2 Clocks (CK)
1: tWR is set to 3 Clocks (CK)
29:28
Back To Back Write-Read commands spacing (DDR different Rows/Bank):
This field determines the WR-RD command spacing, in terms of common clocks for DDR SDRAM
based on the following formula: DQSS + 0.5xBL + TA (WR-RD) – CL
DQSS: is time from Write command to data and is always 1 CK
BL: is Burst Length and can be set to 4.
TA (WR-RD): is required DQ turn-around, can be set to 1 or 2 CK
CL: is CAS Latency, can be set to 2 or 2.5
Examples of usage:
For BL=4, with single DQ turn-around and CL=2, this field must be set to 2 CK (1+2+1-2)
Encoding
00:
CK between WR and RD commands
4
01:
3
2
10:
11:
Reserved
80
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Register Description
27:26
Back To Back Read-Write commands spacing (DDR, same or different Rows/Bank): This
field determines the RD-WR command spacing, in terms of common clocks based on the following
formula: CL + 0.5xBL + TA (RD-WR) – DQSS
DQSS: is time from Write command to data and is always 1 CK
BL: is Burst Length which is set to 4
TA (RD-WR): is required DQ turn-around, can be set to 1, 2 or 3 CK
CL: is CAS latency, can be set to 2 or 2.5
Examples of usage:
For BL=4, with single DQ turn-around and CL=2, this field must be set to 4 CK (2+2+1-1)
Encoding
00:
CK between RD and WR commands
7
6
5
4
01:
10:
11:
NOTE: Since reads in DDR SDRAM cannot be terminated by Writes, the Space between
commands is not a function of Cycle Length but of Burst Length.
25
Back To Back Read-Read commands spacing (DDR, different Rows):
This field determines the RD-RD Command Spacing, in terms of common clocks based on the
following formula: 0.5xBL + TA(RD-RD)
BL: is Burst Length and can be set to 4.
TA (RD-RD): is required DQ turn-around, can be set to 1 or 2 CK
Examples of usage:
For BL=4, with single DQ turn-around, this field must be set to 3 CK (2+1)
Encoding
CK between RD and RD commands
0:
1:
4
3
NOTE: Since a Read to a different row does not terminate a Read, the Space between commands
is not a function of Cycle Length but of Burst Length.
24:15
14:12
Reserved
Refresh Cycle Time (tRFC):
Refresh Cycle Time is measured for a given row from REF command (to perform a refresh) until
following ACT to same row (to perform a Read or Write). It is tracked separately from tRC for DDR
SDRAM.
Current DDR SDRAM spec requires tRFC of 75 ns (DDR266) and 80 ns (DDR200). Therefore, this
field will be set to 8 clocks for DDR200, 10 clocks for DDR266.
Encoding
000:
tRFC
14
clocks
clocks
clocks
clocks
clocks
clocks
clocks
clocks
001:
13
12
11
10
9
010:
011:
100:
101:
110:
8
111:
7
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Intel 82854 Graphics Memory Controller Hub (GMCH)
11
Activate to Precharge delay (tRAS), MAX:
This bit controls the maximum number of clocks that a DDR SDRAM bank can remain open. After
this time period, the system memory Controller will guarantee to pre-charge the bank. Note that
this time period may or may not be set to overlap with time period that requires a refresh to
happen.
The DDR SDRAM Controller includes a separate tRAS-MAX counter for every supported bank.
With a maximum of four rows and four banks per row, there are 16 counters.
0: 120 micro-seconds
1: Reserved.
10:9
Activate to Precharge delay (tRAS), MIN:
This bit controls the number of DDR SDRAM clocks for tRAS MIN
00: 8 Clocks
01: 7 Clocks
10: 6 Clocks
11: 5 Clocks
8:7
6:5
Reserved
CAS# Latency (tCL):
Encoding
00:
DDR SDRAM CL
2.5
01:
2
10:
Reserved
Reserved
11:
4
Reserved
3:2
DDR SDRAM RAS# to CAS# Delay (tRCD): This bit controls the number of clocks inserted
between a Row Activate command and a Read or Write command to that row.
Encoding
00:
tRCD
4 DDR SDRAM Clocks (DDR 333 SDRAM)
3 DDR SDRAM Clocks
2 DDR SDRAM Clocks
Reserved
01:
10:
11:
1:0
DDR SDRAM RAS# Precharge (tRP): This bit controls the number of clocks that are inserted
between a row precharge command and an activate command to the same row.
Encoding
00:
tRP
4 DDR SDRAM Clocks (DDR 333 SDRAM)
3 DDR SDRAM Clocks
2 DDR SDRAM Clocks
Reserved
01:
10:
11:
82
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Register Description
4.9.15
PWRMG – DRAM Controller Power Management Control Register
(Device #0)
Address Offset:
Default Value:
Access:
68-6Bh
00000000h
Read/Write
32 bits
Size:
Bit
Description
Reserved
31:24
23:20
Row State Control: This field determines the number of clocks the System Memory Controller
will remain in the idle state before it begins pre-charging all pages or powering down rows.
- PDEn: Power Down Enable
- PCEn: Page Close Enable
- TC: Timer Control
PDEn(23):
PCEn(22):
TC(21:20)
Function
0
0
1
1
1
1
0
1
0
1
1
1
XX
XX
XX
00
All Disabled
Reserved
Reserved
Immediate Precharge and Powerdown
Reserved
01
10
Precharge and Power Down after 16 DDR
SDRAM Clocks
1
1
11
Precharge and Power Down after 64 DDR
SDRAM Clocks
19:16
15
Reserved
Self Refresh GMCH Memory Interface Data Bus Power Management Optimization Enable:
0 = Enable
1 = Disable
14
13
12
11
CS# Signal Drive Control:
0 = Enable CS# Drive Control, based on rules described in DRC bit 12.
1 = Disable CS# Drive Control, based on rules described in DRC bit 12.
Self Refresh GMCH Memory Interface Data Bus Power Management:
0 = In Self Refresh Mode GMCH Power Management is Enabled.
1 = In Self Refresh Mode the GMCH Power Management is Disabled.
Dynamic Memory Interface Power Management:
0 = Dynamic Memory Interface Power Management Enabled.
1 = Dynamic Memory Interface Power Management Disabled.
Rcven DLL shutdown disable:
0 = Normal operation. RCVEN DLL is turned off when the corresponding SO-DIMM is
unpopulated.
1 = RCVEN DLL is turned on irrespective of SO-DIMM population.
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
10
9:1
0
Reserved.
Reserved
Power State S1/S3 Refresh Control:
0 = Normal Operation, Pending refreshes are not completed before entering Self Refresh for S1/
S3.
1 = All Pending Refreshes plus one extra is performed before entering Self Refresh for S1/S3.
84
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Register Description
4.9.16
DRC – DRAM Controller Mode Register (Device #0)
Address Offset:
Default Value:
Access:
70-73h
00000081h
RO, Read/Write
32 bits
Size:
Bit
Description
31:30
Revision Number (REV): Reflects the revision number of the format used for DDR SDRAM
register definition (Read Only).
29
Initialization Complete (IC): This bit is used for communication of software state between the
Memory Controller and the BIOS. BIOS sets this bit to 1 after initialization of the DDR SDRAM
Memory Array is complete. Setting this bit to a 1 enables DDR SDRAM Refreshes. On power up
and S3 exit, the BIOS initializes the DDR SDRAM array and sets this bit to a 1. This bit works in
combination with the RMS bits in controlling Refresh state:
IC Refresh State
0
1
OFF
ON
28:24
23:22
Reserved
Number of Channels (CHAN): Reflects that GMCH supports only one system memory channel.
00: One channel is populated appropriately
Others: Reserved
21:20
DDIM DDR SDRAM Data Integrity Mode:
00: ECC is not supported on this system. Thus, no read-merge-write on partial writes. ECC data
sense-amps are disabled and the data output is tristate (Default).
XX: Reserved
19:16
15
Reserved
RAS Lock-Out Enable: Set to a 1 if all populated rows support RAS Lock-Out. Defaults to 0.
If this bit is set to a 1 the DDR SDRAM Controller assumes that the DDR SDRAM guarantees
tRAS min before an auto precharge (AP) completes (Note: An AP is sent with a Read or a Write
command). Also, the DDR SDRAM Controller does not issue an activate command to the auto pre-
charged bank for tRP.
If this bit is set to a 0 the DDR SDRAM Controller does not schedule an AP if tRAS min is not met.
14:13
12
Reserved
Address Tri-state enable (ADRTRIEN): When set to a 1, the SDRAM Controller will tri-state the
MA, CMD, and CS# (only when all CKEs are deasserted). Note that when CKE to a row is
deasserted, fast chip select assertion is not permitted by the hardware. CKEs deassert based on
Idle Timer and/or max row count control.
0: Address Tri-state Disabled
1: Address Tri-state Enabled
11:10
Reserved
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
9:7
Refresh Mode Select (RMS): This field determines whether Refresh is enabled and, if so, at what
rate Refreshes will be executed.
000:
001:
010:
011:
111:
Refresh disabled
Refresh enabled. Refresh interval 15.6 µsec
Refresh enabled. Refresh interval 7.8 µsec
Reserved.
Refresh enabled. Refresh interval 64 clocks (fast refresh mode)
Other: Reserved
Any change in the programming of this field Resets the Refresh counter to zero. This function is for
testing purposes, it allows test program to align refresh events with the test and thus improve
failure repeatability.
86
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Register Description
6:4
Mode Select (SMS). These bits select the special operational mode of the DDR SDRAM
Interface. The special modes are intended for initialization at power up.
000: Post Reset State – When the GMCH exits Reset (power-up or otherwise), the mode select
field is cleared to 000. Software is not expected to Write this value, however if this value is Written,
there are no side effects (no Self Refresh or any other special DDR SDRAM cycle).
During any Reset sequence, while power is applied and Reset is active, the GMCH deasserts all
CKE signals. After internal Reset is deasserted, CKE signals remain deasserted until this field is
written to a value different than 000. On this event, all CKE signals are asserted.
During Suspend (S3, S4), GMCH internal signal triggers DDR SDRAM Controller to flush pending
commands and enter all rows into Self-Refresh mode. As part of Resume sequence, GMCH will
be Reset , which will clear this bit field to 000 and maintain CKE signals deasserted. After internal
Reset is deasserted, CKE signals remain deasserted until this field is Written to a value different
than 000. On this event, all CKE signals are asserted.
During Entry to other low power states (C3, S1-M), GMCH internal signal triggers DDR SDRAM
Controller to flush pending commands and enter all rows in S1 and relevant rows in C3 (Based on
RPDNC3) into Self-Refresh mode. During exit to Normal mode, the GMCH signal triggers DDR
SDRAM Controller to Exit Self-Refresh and Resume Normal operation without S/W involvement.
001: NOP Command Enable – All CPU cycles to DDR SDRAM result in a NOP command on the
DDR SDRAM interface.
010: All Banks Pre-charge Enable – All CPU cycles to DDR SDRAM result in an All Banks
Precharge command on the DDR SDRAM interface.
011: Mode Register Set Enable – All CPU cycles to DDR SDRAM result in a Mode Register set
command on the DDR SDRAM Interface. Host address lines are mapped to DDR SDRAM
address lines in order to specify the command sent. Host address HA[13:3] are mapped to
Memory address SMA[11,9:0]. SMA3 must be driven to 1 for interleave wrap type.
For Double Data Rate
MA[6:4] needs to be driven based on the value programmed in the CAS# Latency field.
CAS Latency MA[6:4]
1.5 Clocks
2.0 Clocks
2.5 Clocks
001
010
110
SMA[7] should always be driven to a 0.
SMA[8] Should be driven to a 1 for DLL Reset and 1 for Normal Operation.
SMA[12:9] must be driven to 00000.
BIOS must calculate and drive the correct host address for each row of Memory such that the
correct command is driven on the SMA[12:0] lines. Note that SMAB[5,4,2,1]# are inverted from
SMA[5,4,2,1]; BIOS must account for this.
100: Extended Mode Register Set Enable – All CPU cycles to DDR SDRAM result in an
“Extended Mode register set” command on the DDR SDRAM Interface. Host address lines are
mapped to DDR SDRAM address lines in order to specify the command sent. Host address lines
are mapped to DDR SDRAM address lines in order to specify the command sent. Host address
HA[13:3] are mapped to Memory address SMA[11,9:0]. SMA[0] = 0 for DLL enable and 1 for DLL
disable. All the other SMA lines are driven to 0’s. Note that SMAB[5,4,2,1]# are inverted from
SMA[5,4,2,1]; BIOS must account for this.
101: Reserved
110: CBR Refresh Enable – In this mode all CPU cycles to DDR SDRAM result in a CBR cycle on
the DDR SDRAM interface
111: Normal operation
3:0
Reserved
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
4.9.17
DTC – DRAM Throttling Control Register (Device #0)
Address Offset:
Default Value:
Access:
A0-A3h
00000000h
Read/Write/Lock
32 bits
Size:
Throttling is independent for system memory banks, GMCH Writes, and Thermal Sensor Trips.
Read and Write Bandwidth is measured independently for each bank. If the number of Octal -
Words (16 bytes) Read/Written during the window defined below (Global DDR SDRAM Sampling
Window: GDSW) exceeds the DDR SDRAM Bandwidth Threshold, then the DDR SDRAM
Throttling mechanism will be invoked to limit DDR SDRAM Reads/Writes to a lower bandwidth
checked over smaller time windows. The throttling will be active for the remainder of the current
GDSW and for the next GDSW after which it will return to Non-Throttling mode. The throttling
mechanism accounts for the actual bandwidth consumed during the sampling window, by reducing
the allowed bandwidth within the smaller throttling window based on the bandwidth consumed
during the sampling period. Although bandwidth from/to independent rows and GMCH Write
bandwidth is measured independently, once Tripped all transactions except high priority graphics
Reads are subject to throttling.
88
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Register Description
Bit
Description
31:28
DDR SDRAM Throttle Mode (TMODE):
Four bits control which mechanisms for Throttling are enabled in an “OR” fashion. Counter-
based Throttling is lower priority than Thermal Trips Throttling when both are enabled and
Tripped. Counter-based trips point Throttling values and Thermal-based Trip Point Throttling
values are specified in this register.
If the counter and thermal mechanisms for either Rank or GMCH are both enabled, Throttle
settings for the one that Trips first is used until the end of the second gdsw.
[Rank Counter, GMCH Write Counter, Rank Thermal Sensor, GMCH Thermal Sensor]
0000 = Throttling turned off. This is the default setting. All Counters are off.
0001 = Only GMCH Thermal Sensor based Throttling is enabled. If GMCH Thermal Sensor is
Tripped, Write Throttling begins based on the setting in WTTC.
0010 = Only Rank Thermal Sensor based Throttling is enabled. When the external SO-DIMM
Thermal sensor is Tripped, DDR SDRAM Throttling begins based on the setting in RTTC.
0011 = Both Rank and GMCH Thermal Sensor based throttling is enabled. When the external
SO-DIMM Thermal Sensor is Tripped DDR SDRAM Throttling begins based on the setting in
RTTC. If the GMCH Thermal Sensor is Tripped, Write Throttling begins based on the setting in
WTTC.
0100 = Only the GMCH Write Counter mechanism is enabled. When the length of write
transfers programmed (GDSW * WCTC) is reached, DRAM throttling begins based on the
setting in WCTC..
0101 = GMCH Thermal Sensor and GMCH Write DDR SDRAM Counter mechanisms are both
enabled. If the GMCH Write DDR SDRAM Counter mechanism threshold is reached, DDR
SDRAM Throttling begins based on the setting in WCTC. If the GMCH Thermal Sensor is
tripped, DDR SDRAM Throttling begins based on the setting in WTTC. If both threshold
mechanisms are tripped, the DDR SDRAM Throttling begins based on the settings in WTTC.
0110 = Rank Thermal Sensor and GMCH Write DDR SDRAM Counter mechanisms are both
enabled. If the GMCH Write DDR SDRAM Counter mechanism threshold is reached, DDR
SDRAM Throttling begins based on setting in WCTC. If the external SO-DIMM Thermal Sensor
is tripped, Rank DDR SDRAM throttling begins based on the setting in RTTC.
0111 = Similar to 0101 for Writes and when the Rank Thermal Sensor is tripped, DDR SDRAM
Throttling begins based on the setting in RTTC.
1000 = Only Rank Counter mechanism is enabled. When the length of read transfers
programmed (GDSW * RCTC) is reached, DRAM throttling begins based on the setting in
RCTC
1001 = Rank Counter mechanism is enabled and GMCH Thermal Sensor based throttling are
both enabled. If GMCH thermal sensor is tripped, write throttling begins based on the setting in
WTTC. If the rank counter mechanism is tripped, DRAM throttling begins based on the setting
in RCTC.
1010 = Rank Thermal Sensor and Rank DDR SDRAM Counter mechanisms are both enabled.
If the rank DDR SDRAM Counter mechanism threshold is reached, DDR SDRAM Throttling
begins based on the setting in RCTC. If the external SO-DIMM Thermal Sensor is tripped,
DRAM Throttling begins based on the setting in RTTC.
1011 = Similar to 1010 and if the GMCH Thermal Sensor is tripped, Write Throttling begins
based on the setting in WTTC.
1111 = Rank and GMCH Thermal Sensor based Throttling and Rank and GMCH Write Counter
based Throttling are enabled. If both the Write Counter and GMCH Thermal Sensor based
mechanisms are tripped, DDR SDRAM Throttling begins based on the setting allowed in WTTC.
If both the Rank Counter and Rank Thermal Sensor based mechanisms are tripped, DDR
SDRAM Throttling begins based on the setting allowed in RTTC.
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
27:24
23:20
19:16
Read Counter Based Power Throttle Control (RCTC): These bits select the Counter based
Power Throttle Bandwidth Limits for Read operations to system memory.
R/W, RO if Throttle Lock.
0h = 85%
1h = 70%
2h = 65%
3h = 60%
4h = 55%
5h = 50%
6h = 45%
7h = 40%
8h = 35%
9h = 30%
Ah = 20%
B-Fh = Reserved
Write Counter Based Power Throttle Control (WCTC): These bits select the counter based
Power Throttle Bandwidth Limits for Write operations to system memory.
R/W, RO if Throttle Lock
0h = 85%
1h = 70%
2h = 65%
3h = 60%
4h = 55%
5h = 50%
6h = 45%
7h = 40%
8h = 35%
9h = 30%
Ah = 20%
B-Fh = Reserved
Read Thermal Based Power Throttle Control (RTTC): These bits select the Thermal Sensor
based Power Throttle Bandwidth Limits for Read operations to system memory.
R/W, RO if Throttle Lock.
0h = 85%
1h = 70%
2h = 65%
3h = 60%
4h = 55%
5h = 50%
6h = 45%
7h = 40%
8h = 35%
9h = 30%
Ah = 20%
B-Fh = Reserved
90
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Register Description
15:12
Write Thermal Based Power Throttle Control (WTTC): These bits select the Thermal based
Power Throttle Bandwidth Limits for Write operations to system memory.
R/W, RO if Throttle Lock
0h = 85%
1h = 70%
2h = 65%
3h = 60%
4h = 55%
5h = 50%
6h = 45%
7h = 40%
8h = 35%
9h = 30%
Ah = 20%
B-Fh = Reserved
11
10
Counter Based Throttle Lock (CTLOCK): This bit secures RCTC and WCTC. This bit defaults
to 0. Once a 1 is written to this bit, RCTC and WCTC (including CTLOCK) become Read-Only.
Thermal Throttle Lock (TTLOCK): This bit secures the DDR SDRAM Throttling Control
register. This bit defaults to 0. Once a 1 is written to this bit, all of the configuration register bits
in DTC (including TTLOCK) except CTLOCK, RCTC and WCTC become Read-Only.
9
8
Thermal Power Throttle Control fields Enable:
0 = RTTC and WTTC are not used. RCTC and WTCT are used for both Counter and Thermal
based Throttling.
1 = RTTC and WTTC are used for Thermal based Throttling.
High Priority Stream Throttling Enable:
Normally High Priority Streams are not Throttled when either the counter based mechanism or
Thermal Sensor mechanism demands Throttling.
0 = Normal operation.
1 = Block High priority streams during Throttling.
7:0
Global DDR SDRAM Sampling Window (GDSW): This 8-bit value is multiplied by 4 to define
the length of time in milliseconds (0–1020) over which the number of Octal Words (16 bytes)
Read/Written is counted and Throttling is imposed. Note that programming this field to 00h
disables system memory throttling.
Recommended values are between 0.25 and 0.75 seconds.
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
4.10
Intel 854 GMCH Configuration Process Registers (Device
#0, Function #3)
summarizes all Device#0, Function #3 registers.
Table 23.
Configuration Process Configuration Space (Device#0, Function #3)
Register
Symbol
Register
Start
Register
End
Register Name
Default Value
Access
Vendor Identification
Device Identification
PCI Command
VID
DID
00
02
04
06
08
0A
0B
0E
2C
2E
34
C0
01
03
05
07
08
0A
0B
0E
2D
2F
34
C1
8086h
358Ch
0006h
0080h
02h
RO
RO
PCICMD
PCISTS
RID
RO,R/W
RO,R/WC
RO
PCI Status
Revision Identification
Sub-Class Code
SUBC
BCC
80h
RO
Base Class Code
08h
RO
Header Type
HDR
80h
RO
Subsystem Vendor Identification
Subsystem Identification
Capabilities Pointer
HPLL Clock Control
SVID
0000h
0000h
00h
R/WO
R/WO
RO
SID
CAPPTR
HPLLCC
00h
RO
4.10.1
VID – Vendor Identification Register
Address Offset:
Default Value:
Access:
00-01h
8086h
Read Only
16 bits
Size:
The VID Register contains the vendor identification number. This 16-bit register combined with
the Device Identification register uniquely identifies any PCI device. Writes to this register have no
effect.
Bit
Descriptions
15:0
Vendor Identification (VID): This register field contains the PCI standard identification for
8086h.
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Register Description
4.10.2
DID – Device Identification Register
Address Offset:
Default Value:
Access:
02-03h
358Ch
Read Only
16 bits
Size:
This 16-bit register combined with the Vendor Identification register uniquely identifies any PCI
device. Writes to this register have no effect.
Bit
Descriptions
15:0
Device Identification Number (DID): This is a 16-bit value assigned to the Intel 854 GMCH
Host-HI Bridge Function #3 (358Ch).
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
4.10.3
PCICMD – PCI Command Register
Address Offset:
Default Value:
Access:
04-05h
0006h
Read Only, Read/Write
16 bits
Size:
®
Since the Intel 82854 GMCH Device #0 does not physically reside on PCI_A many of the bits are
not implemented.
Bit
Descriptions
Reserved
15:10
9
Fast Back-to-Back Enable (FB2B): This bit controls whether or not the master can do fast back-
to-back Write. Since Device #0 is strictly a target, this bit is not implemented and is hardwired to
0. Writes to this bit position have no effect.
8
7
6
5
4
SERR Enable (SERRE): SERR# is not implemented by Function #1 of Device #0 of the GMCH
and this bit is hardwired to 0. Writes to this bit position have no effect.
Address/Data Stepping Enable (ADSTEP): Address/data stepping is not implemented in the
GMCH, and this bit is hardwired to 0. Writes to this bit position have no effect.
Parity Error Enable (PERRE): PERR# is not implemented by GMCH and this bit is hardwired to
0. Writes to this bit position have no effect.
VGA Palette Snoop Enable (VGASNOOP): The GMCH does not implement this bit and it is
hardwired to a 0. Writes to this bit position have no effect.
Memory Write and Invalidate Enable (MWIE): The GMCH will never issue Memory Write and
Invalidate commands. This bit is therefore hardwired to 0. Writes to this bit position will have no
effect.
3
2
1
0
Special Cycle Enable (SCE): The GMCH does not implement this bit and it is hardwired to a 0.
Writes to this bit position have no effect.
Bus Master Enable (BME): The GMCH is always enabled as a master on HI. This bit is
hardwired to a 1. Writes to this bit position have no effect.
Memory Access Enable (MAE): The GMCH always allows access to Main Memory. This bit is
not implemented and is hardwired to 1. Writes to this bit position have no effect.
I/O Access Enable (IOAE): This bit is not implemented in the GMCH and is hardwired to a 0.
Writes to this bit position have no effect.
94
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Register Description
4.10.4
PCISTS – PCI Status Register
Address Offset:
Default Value:
Access:
06-07h
0080h
Read Only, Read/Write Clear
16 bits
Size:
PCISTS is a 16-bit status register that reports the occurrence of error events on Device #0's PCI
Interface. Bit 14 is Read/Write clear. All other bits are Read Only. Since GMCH Device #0 does
not physically reside on PCI_A many of the bits are not implemented.
Bit
Descriptions
15
Detected Parity Error (DPE): The GMCH does not implement this bit and it is hardwired to a 0.
Writes to this bit position have no effect.
14
Signaled System Error (SSE): The GMCH does not implement this bit and it is hardwired to a 0.
Writes to this bit position have no effect.
13
Received Master Abort Status (RMAS): The GMCH does not implement this bit and it is
hardwired to a 0. Writes to this bit position have no effect.
12
Received Target Abort Status (RTAS): The GMCH does not implement this bit and it is
hardwired to a 0. Writes to this bit position have no effect.
11
Signaled Target Abort Status (STAS): The GMCH does not implement this bit and it is
hardwired to a 0. Writes to this bit position have no effect.
10:9
DEVSEL Timing (DEVT): These bits are hardwired to "00". Writes to these bit positions have no
affect. Device #0 does not physically connect to PCI_A. These bits are set to "00" (fast decode)
so that the GMCH does not limit optimum DEVSEL timing for PCI_A.
8
7
Master Data Parity Error Detected (DPD): The GMCH does not implement this bit and it is
hardwired to a 0. Writes to this bit position have no effect.
Fast Back-to-Back (FB2B): This bit is hardwired to 1. Writes to these bit positions have no
effect. Device #0 does not physically connect to PCI_A. This bit is set to 1 (indicating fast back-to-
back capability) so that the GMCH does not limit the optimum setting for PCI_A.
6:5
4
Reserved
Capability List (CLIST): This bit is hardwired to 0 to indicate to the configuration software that
this device/function does not implement new capabilities.
3:0
Reserved
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Intel 82854 Graphics Memory Controller Hub (GMCH)
4.10.5
4.10.6
4.10.7
RID – Revision Identification Register
Address Offset:
Default Value:
Access:
08h
02h
Read Only
8 bits
Size:
®
This register contains the revision number of the Intel 82854 GMCH. These bits are Read Only
and Writes to this register have no effect.
Bit
Descriptions
7:0
Revision Identification Number (RID): This is an 8-bit value that indicates the revision
identification number for the GMCH.
SUBC – Sub-Class Code Register
Address Offset:
Default Value:
Access:
0Ah
80h
Read Only
8 bits
Size:
®
This register contains the Sub-Class Code for the Intel 82854 GMCH Device #0. This code is 80h
indicating a peripheral device.
Bit
Descriptions
7:0
Sub-Class Code (SUBC): This is an 8-bit value that indicates the category of Bridge into which
GMCH falls. The code is 80h indicating other peripheral device.
BCC – Base Class Code Register
Address Offset:
Default Value:
Access:
0Bh
08h
Read Only
8 bits
Size:
®
This register contains the Base Class Code of the Intel 82854 GMCH Device #0 Function #3.
This code is 08h indicating a peripheral device.
Bit
Descriptions
7:0
Base Class Code (BASEC): This is an 8-bit value that indicates the Base Class code for the
GMCH. This code has the value 08h, indicating other peripheral device.
96
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Register Description
4.10.8
HDR – Header Type Register
Address Offset:
Default Value:
Access:
0Eh
80h
Read Only
8 bits
Size:
This register identifies the header layout of the configuration space. No physical register exists at
this location.
Bit
Descriptions
7:0
PCI Header (HDR): This field always returns 80 to indicate that Device #0 is a multifunction
device. If Functions other than #0 are disabled this field returns a 00 to indicate that the GMCH is
a single function device with standard header layout. The default is 80 Reads and Writes to this
location have no effect.
4.10.9
SVID – Subsystem Vendor Identification Register
Address Offset:
Default Value:
Access:
2C-2Dh
0000h
Read/Write Once
16 bits
Size:
This value is used to identify the vendor of the subsystem.
Bit
Descriptions
15:0
Subsystem Vendor ID (SUBVID): This field should be programmed during boot-up to indicate
the vendor of the system board. After it has been Written once, it becomes Read Only.
4.10.10
ID – Subsystem Identification Register
Address Offset:
Default Value:
Access:
2E-2Fh
0000h
Read/Write Once
16 bits
Size:
This value is used to identify a particular subsystem.
Bit
Descriptions
7:0
Subsystem ID (SUBID): This field should be programmed during BIOS initialization. After it has
been Written once, it becomes Read Only.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
4.10.11
CAPPTR – Capabilities Pointer Register
Address Offset:
Default Value:
Access:
34h
00h
Read Only
8 bits
Size:
The CAPPTR provides the offset that is the pointer to the location of the first device capability in
the capability list.
Bit
Descriptions
7:0
Pointer to the offset of the first capability ID register block: In this case there are no
capabilities therefore these bits are hardwired to 00h to indicate the end of the capability-linked
list.
4.10.12
HPLLCC – HPLL Clock Control Register (Device #0)
Address Offset:
Default Value:
Access:
C0-C1h
00h
Read Only
16 bits
Size:
Bit
Descriptions
15:11
10
Reserved
HPLL VCO Change Sequence Initiate Bit:
Software must Write a 0 to clear this bit and then Write a 1 to initiate sequence again.
9
Hphase Reset Bit:
1 = Assert
0 = Deassert (default)
8
Reserved
Reserved
7:2
1:0
HPLL Clock Control:
Software is allowed to update this register.
98
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Register Description
®
Table 24.
Intel 82854 GMCH Configurations and Some Resolution Examples: Native
Graphics Mode
Straps Read
Through
HPLLCC[2:0]:
D0:F3:Register
Offset C0-C1h,
bits[2:0]
GFX Core
Clock(Low)
GFX Core
System
Memory
Frequency
FSB
Rate
DVO Port
CRT Port
Clock (High)
000
111
400
MHz
266 MHz
333 MHz
200 MHz
1600x1200@85 Hz
DCLK = 229- MHz
1600x1200@85-Hz
DCLK = 229 -MHz
2048x1536@72 Hz
DCLK = 324 MHz
2048x1536@75 Hz
DCLK = 340 MHz
400
MHz
250 MHz
1600x1200@85 Hz
DCLK = 229 MHz
1600x1200@85 Hz
DCLK = 229 MHz
2048x1536@72 Hz
DCLK = 324 MHz
2048x1536@75 Hz
DCLK = 340 MHz
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Intel 82854 Graphics Memory Controller Hub (GMCH)
4.11
Intel® 82854 GMCH Integrated Graphics Device Registers
(Device #2, Function #0)
This section contains the PCI configuration registers listed in order of ascending offset address.
access nomenclature.
Note: C0F0 = Copy of Function #0 and U1F1 = Unique in Function #1.
Table 25.
Integrated Graphics Device Configuration Space (Device #2, Function#0)
Register
Symbol
Address
Offset
Register
End
Default
Value
Regs in
Function#1
Register Name
Access
Vendor Identification
Device Identification
PCI Command
VID
DID
00h
02h
04h
06h
08h
09h
0Ch
0Dh
0Eh
10h
01h
03h
05h
07h
08h
0Bh
0Ch
0Dh
0Eh
13h
8086h
358Eh
0000h
0090h
02h
RO
RO
C0F0
C0F0
U1F1
U1F1
C0F0
U1F1
C0F0
C0F0
C0F0
U1F1
PCICMD
PCISTS
RID
RO,R/W
RO
PCI Status
Revision Identification
Class Code
RO
CC
030000h
00h
RO
Cache Line Size
Master Latency Timer
Header Type
CLS
RO
MLT
00h
RO
HDR
00h
RO
Graphics Memory
Range Address
GMADR
00000008h
RO,R/W
Memory Mapped Range
Address
MMADR
14h
17h
00000000h
RO,R/W
U1F1
IO Range
IOBAR
SVID
18h
2Ch
2Eh
30h
1Bh
2Dh
2Fh
33h
00000001h
0000h
RO,R/W
R/WO
R/ WO
RO
–
Subsystem Vendor ID
Subsystem ID
C0F0
C0F0
C0F0
SID
0000h
Video Bios ROM Base
Address
ROMADR
00000000h
Interrupt Line
Interrupt Pin
INTRLINE
INTRPIN
3Ch
3Dh
3Ch
3Dh
00h
01h
RO in F#1,
R/W
–
–
RO, Reserved
In F#1
Minimum Grant
MINGNT
MAXLAT
PMCAP
3Eh
3Fh
D2h
3Eh
3Fh
D3h
00h
00h
RO
RO
RO
C0F0
C0F0
C0F0
Maximum Latency
Power Management
Capabilities
0221h
Power Management
Control
PMCS
D4h
D5h
0000h
RO,R/W
U1F1
100
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Register Description
4.11.1
VID – Vendor Identification Register (Device #2)
Address Offset:
Default Value:
Access:
00-01h
8086h
Read Only
16 bits
Size:
The VID Register contains the vendor identification number. This 16-bit register combined with
the Device Identification Register uniquely identifies any PCI device. Writes to this register have
no effect.
Bit
Description
15:0
Vendor Identification Number: This is a 16-bit value assigned to Intel.
4.11.2
DID – Device Identification Register (Device #2)
Address Offset:
Default Value:
Access:
02-03h
358Eh
Read Only
16 bits
Size:
This 16-bit register combined with the Vendor Identification register uniquely identifies any PCI
device. Writes to this register have no effect.
Bit
Description
15:0
Device Identification Number: This is a 16-bit value assigned to the GMCH IGD (358Eh).
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Intel 82854 Graphics Memory Controller Hub (GMCH)
4.11.3
PCICMD – PCI Command Register (Device #2)
Address Offset:
Default Value:
Access:
04-05h
0000h
Read Only, Read/Write
16 bits
Size:
This 16-bit register provides basic control over the IGD's ability to respond to PCI cycles. The
PCICMD register in the IGD disables the IGD PCI compliant master accesses to main system
memory.
Bit
Description
15:10
Reserved
9
8
7
6
5
4
3
2
Fast Back-to-Back (FB2B)–RO
SERR# Enable (SERRE) –RO
Address/Data Stepping–RO
Parity Error Enable (PERRE) –RO
Video Palette Snooping (VPS) –RO
Memory Write and Invalidate Enable (MWIE) –RO
Special Cycle Enable (SCE) –RO
Bus Master Enable (BME) –R/W: This bit determines if the IGD is to function as a PCI compliant
master.
0= Disable IGD bus mastering (default).
1 = Enable IGD bus mastering.
1
0
Memory Access Enable (MAE) –R/W: This bit controls the IGD’s response to System Memory
Space accesses.
0= Disable (default).
1 = Enable.
I/O Access Enable (IOAE) –R/W: This bit controls the IGD’s response to I/O Space accesses.
0 = Disable (default).
1 = Enable.
102
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Register Description
4.11.4
PCISTS – PCI Status Register (Device #2)
Address Offset:
Default Value:
Access:
06-07h
0090h
Read Only
16 bits
Size:
PCISTS is a 16-bit status register that reports the occurrence of a PCI compliant master abort and
PCI compliant target abort. PCISTS also indicates the DEVSEL# timing that has been set by the
IGD.
Bit
Description
15
14
13
12
11
10:9
8
Detected Parity Error (DPE): Since the IGD does not detect parity, this bit is always set to 0.
Signaled System Error (SSE) – RO
Received Master Abort Status (RMAS) – RO
Received Target Abort Status (RTAS) – RO
Signaled Target Abort Status (STAS) – RO
DEVSEL# Timing (DEVT) – RO
Data Parity Detected (DPD) – RO
7
Fast Back-to-Back (FB2B) – RO
6
User Defined Format (UDF) – RO
5
66-MHz PCI Capable (66C) – RO
4
CAP LIST: This bit is set to 1 to indicate that the register at 34h provides an offset into the
Function’s PCI Configuration Space containing a pointer to the location of the first item in the list.
3:0
Reserved
4.11.5
RID – Revision Identification Register (Device #2)
Address Offset:
Default Value:
Access:
08h
02h
Read Only
8 bits
Size:
This register contains the revision number of the IGD. These bits are Read Only and Writes to this
register have no effect.
Bit
Description
7:0
Revision Identification Number: This is an 8-bit value that indicates the revision identification
number for the GMCH.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
4.11.6
CC – Class Code Register (Device #2)
Address Offset:
Default Value:
Access:
09-0Bh
030000h
Read Only
24 bits
Size:
This register contains the device programming interface information related to the Sub-Class code
and Base Class code definition for the IGD. This register also contains the Base Class code and the
function sub-class in relation to the Base Class code.
Bit
Description
23:16
15:8
Base Class Code (BASEC): 03=Display controller
Sub-Class Code (SCC):
Function 0: 00h=VGA compatible or 80h=Non VGA
Function 1: 80h=Non VGA
7:0
Programming Interface (PI): 00h=Hardwired as a Display controller.
4.11.7
CLS – Cache Line Size Register (Device #2)
Address Offset:
Default Value:
Access:
0Ch
00h
Read Only
8 bits
Size:
The IGD does not support this register as a PCI slave.
Bit
Description
7:0
Cache Line Size (CLS) – RO
4.11.8
MLT – Master Latency Timer Register (Device #2)
Address Offset:
Default Value:
Access:
0Dh
00h
Read Only
8 bits
Size:
The IGD does not support the programmability of the master latency timer because it does not
perform bursts.
104
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Register Description
Bit
Description
7:0
Master Latency Timer Count Value – RO
4.11.9
HDR – Header Type Register (Device #2)
Address Offset:
Default Value:
Access:
0Eh
00h
Read Only
8 bits
Size:
This register contains the Header Type of the IGD.
Bit
Description
7
Multi Function Status (MFunc): Indicates if the device is a multi-function device.
6:0
Header Code (H): This is a 7-bit value that indicates the Header code for the IGD. This code has
the value 00h, indicating a type 0 configuration space format.
4.11.10
GMADR – Graphics Memory Range Address Register (Device #2)
Address Offset:
Default Value:
Access:
10-13h
00000008h
Read/Write, Read Only
32 bits
Size:
IGD graphics system memory base address is specified in this register.
Bit
Description
31:27
26
Memory Base Address–R/W: Set by the OS, these bits correspond to address signals [31:26].
128-MB Address Mask – RO: 0 indicates 128-MB address
Address Mask–RO: Indicates (at least) a 32-MB address range.
Prefetchable Memory–RO: Enable prefetching.
25:4
3
2:1
0
Memory Type–RO: Indicates 32-bit address.
Memory/IO Space–RO: Indicates System Memory Space.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
4.11.11
MMADR – Memory Mapped Range Address Register (Device #2)
Address Offset:
Default Value:
Access:
14-17h
00000000h
Read/Write, Read Only
32 bits
Size:
This register requests allocation for the IGD registers and instruction ports. The allocation is for
512-kB and the base address is defined by bits [31:19].
Bit
Description
31:19
18:4
3
Memory Base Address–R/W: Set by the OS, these bits correspond to address signals [31:19].
Address Mask–RO: Indicate 512-kB address range.
Prefetchable Memory–RO: Prevents prefetching.
2:1
0
Memory Type–RO: Indicates 32-bit address.
Memory / IO Space–RO: Indicates System Memory space.
4.11.12
IOBAR – I/O Base Address Register (Device #2)
Address Offset:
Default Value:
Access:
18-1Bh
00000001h
Read/Write
32 bits
Size:
This register provides the Base offset of the I/O registers within Device #2. Bits 15:3 are
programmable allowing the I/O Base to be located anywhere in 16-bit I/O Address Space. Bits 2:1
are fixed and return zero, bit 0 is hardwired to a one indicating that 8-bytes of I/O space are
decoded.
Access to the 8Bs of IO space is allowed in PM state D0 when IO Enable (PCICMD bit 0) set.
Access is disallowed in PM states D1-D3 or if IO Enable is clear or if Device #2 is turned off or if
internal graphics is disabled. Note that access to this IO BAR is independent of VGA functionality
within Device #2. Also note that this mechanism is available only through Function #0 of
Device#2 and is not duplicated in Function #1.
If accesses to this I/O bar are allowed, then the GMCH claims all 8-bit, 16-bit, or 32-bit I/O cycles
from the CPU that falls within the 8B claimed.
Bit
Description
31:16
15:3
2:1
Reserved
IO Base Address–R/W: Set by the OS, these bits correspond to address signals [15:3].
Memory Type–RO: Indicates 32-bit address.
0
Memory / IO Space–RO
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Register Description
4.11.13
4.11.14
4.11.15
SVID – Subsystem Vendor Identification Register (Device #2)
Address Offset:
Default Value:
Access:
2C-2Dh
0000h
Read/Write Once
16 bits
Size:
Bit
Description
15:0
Subsystem Vendor ID: This value is used to identify the vendor of the subsystem. This register
should be programmed by BIOS during boot-up. Once written, this register becomes Read Only.
This register can only be cleared by a reset.
SID – Subsystem Identification Register (Device #2)
Address Offset:
Default Value:
Access:
2E-2Fh
0000h
Read/Write Once
16 bits
Size:
Bit
Description
15:0
Subsystem Identification: This value is used to identify a particular subsystem. This field should
be programmed by BIOS during boot-up. Once written, this register becomes Read Only. This
register can only be cleared by a reset.
ROMADR – Video BIOS ROM Base Address Registers (Device #2)
Address Offset:
Default Value:
Access:
30-33h
00000000h
Read Only
32 bits
Size:
The IGD does not use a separate BIOS ROM, therefore this register is hardwired to 0's.
Bit
Description
31:18
17:11
10:1
0
ROM Base Address–RO
Address Mask–RO: Indicates 256-kB address range.
Reserved
ROM BIOS Enable–RO: Indicates ROM not accessible.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
4.11.16
INTRLINE – Interrupt Line Register (Device #2)
Address Offset:
Default Value:
Access:
3Ch
00h
Read/Write
8 bits
Size:
Bit
Description
7:0
Interrupt Connection: Used to communicate interrupt line routing information. POST software
Writes the routing information into this register as it initializes and configures the system. The value
in this register indicates which input of the System Interrupt controller that the device’s interrupt pin
is connected to.
4.11.17
INTRPIN – Interrupt Pin Register (Device #2)
Address Offset:
Default Value:
Access:
3Dh
01h
Read Only
8 bits
Size:
Bit
Description
7:0
Interrupt Pin: As a single function device, the IGD specifies INTA# as its interrupt pin. 01h=INTA#.
For Function #1, this register is set to 00h.
4.11.18
MINGNT – Minimum Grant Register (Device #2)
Address Offset:
Default Value:
Access:
3Eh
00h
Read Only
8 bits
Size:
Bit
Description
7:0
Minimum Grant Value: The IGD does not burst as a PCI compliant master.
108
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Register Description
4.11.19
MAXLAT – Maximum Latency Register (Device #2)
Address Offset:
Default Value:
Access:
3Fh
00h
Read Only
8 bits
Size:
Bit
Description
7:0
Maximum Latency Value: Bits[7:0]=00h. The IGD has no specific requirements for how often it
needs to access the PCI bus.
4.11.20
PMCAP – Power Management Capabilities Register (Device #2)
Address Offset:
Default Value:
Access:
D2-D3h
0221h
Read Only
16 bits
Size:
Bit
Description
15:11
PME Support: This field indicates the power states in which the IGD may assert PME#. Hardwired
to 0 to indicate that the IGD does not assert the PME# signal.
10:6
5
Reserved
Device Specific Initialization (DSI): Hardwired to 1 to indicate that special initialization of the IGD
is required before generic class device driver is to use it.
4
Auxiliary Power Source: Hardwired to 0.
3
PME Clock: Hardwired to 0 to indicate IGD does not support PME# generation.
2:0
Version: Hardwired to 001b to indicate there are 4 bytes of power management registers
implemented.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
4.11.21
PMCS – Power Management Control/Status Register (Device #2)
Address Offset:
Default Value:
Access:
D4-D5h
0000h
Read/Write, Read Only
16 bits
Size:
Bit
Description
15
PME_Status –RO: This bit is 0 to indicate that IGD does not support PME# generation from D3
(cold).
14:9
8
Reserved
PME_En–RO: This bit is 0 to indicate that PME# assertion from D3 (cold) is disabled.
7:2
1:0
Reserved
PowerState–R/W: This field indicates the current power state of the IGD and can be used to set
the IGD into a new power state. If software attempts to Write an unsupported state to this field,
Write operation must complete normally on the bus, but the data is discarded and no state change
occurs.
On a transition from D3 to D0 the graphics controller is optionally Reset to initial values.
Bits[1:0] Power State
00
01
10
11
D0 Default
D1
D2 Not Supported
D3
110
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®
Intel 82854 GMCH System Address Map
®
5.0
Intel 82854 GMCH System Address Map
A system based on the GMCH supports 4 GB of addressable system memory space and 64 kB+3B
of addressable I/O space. The I/O and system memory spaces are divided by system configuration
software into regions. The system memory ranges are useful either as system memory or as
specialized system memory, while the I/O regions are used solely to control the operation of
devices in the system.
When the GMCH receives a Write request whose address targets an invalid space, the data is
ignored. For Reads, the GMCH responds by returning all zeros on the requesting interface.
5.1
System Memory Address Ranges
The GMCH provides a maximum system memory of 2 GB. The GMCH does not remap APIC
memory space and does not limit DDR SDRAM space in hardware. It is the BIOS or system
designer's responsibility to limit system memory population so that adequate PCI High BIOS and
map in a simplified form and provide details on mapping specific system memory regions as
defined and supported by the GMCH.
Figure 5.
Simplified View of System Address Map
4 GB
Graphics
Memory
Graphic
(Local)
Memory
Address
Range
Top of the
Main Memory
Independently
Programmable
Main
Memory
Address
Range
Non-Overlapping
Memory Windows
0
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
Figure 6.
Detailed View of System Address Map
4 GB max
TOM
1 MB
SBIOS
Upper
0FFFFFh
BIOS Area
(64 kB)
Extended
0F0000h
0EFFFFh
960 kB
896 kB
SBIOS Lower
PCI Memory
Range
BIOS Area ( 64
kB) 16 kB x 4
0E0000h
0DFFFFh
1 GB
16 MB
15 MB
Expansion
Card
BIOS and
Buffer Area
(128 kB)
16 kBx8
Optional ISA
Hole
0C0000h
0BFFFFh
Standard 768 kB
PCI/ISA
Video
Memory
(SMM
Memory)
128 kB
DOS
Compatibility
Memory
1 MB
DOS
Compatibility
Memory
640 kB
0A0000h
09FFFFh
640 kB
0 B
DOS Area
000000h
5.2
DOS Compatibility Area
This compatibility region is divided into the following address regions:
• 0 - 640 kB DOS Area
• 640 - 768 kB Video Buffer Area
• 768 - 896 kB in 16-kB sections (total of eight sections) - expansion area
• 896 -960 kB in 16-kB sections (total of four sections) - extended system BIOS area
• 960 kB - 1 MB system BIOS area
There are 16 system memory segments in the compatibility area. Thirteen of the system memory
ranges can be enabled or disabled independently for both Read and Write cycles.
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®
Intel 82854 GMCH System Address Map
Table 26.
System Memory Segments and Their Attributes
System Memory
Segments
Attributes
Comments
000000H - 09FFFFH
0A0000H - 0BFFFFH
0C0000H - 0C3FFFH
Fixed - always mapped to main
DDR SDRAM
0 to 640 kB – DOS Region
Mapped to Hub interface or IGD
- configurable as SMM space
Video Buffer (physical DDR SDRAM
configurable as SMM space)
WE(Write Enable) RE (Read
Enable)
Add-on BIOS
0C4000H - 0C7FFFH
0C8000H - 0CBFFFH
0CC000H - 0CFFFFH
0D0000H - 0D3FFFH
0D4000H - 0D7FFFH
0D8000H - 0DBFFFH
0DC000H - 0DFFFFH
0E0000H - 0E3FFFH
0E4000H - 0E7FFFH
0E8000H - 0EBFFFH
0EC000H - 0EFFFFH
0F0000H - 0FFFFFH
WE RE
WE RE
WE RE
WE RE
WE RE
WE RE
WE RE
WE RE
WE RE
WE RE
WE RE
WE RE
Add-on BIOS
Add-on BIOS
Add-on BIOS
Add-on BIOS
Add-on BIOS
Add-on BIOS
Add-on BIOS
BIOS Extension
BIOS Extension
BIOS Extension
BIOS Extension
BIOS Area
DOS Area (000000h-09FFFFh)
The DOS area is 640 kB in size and is always mapped to the main system memory controlled by
the GMCH.
Legacy VGA Ranges (0A0000h-0BFFFFh)
®
Legacy VGA ranges is accessible when the Intel 82854 GMCH is strapped into Native Graphics
mode. The legacy 128-kB VGA memory range A0000h-BFFFFh (VGA Frame Buffer) can be
mapped to IGD (Device #2) and to the Hub interface depending on the programming of the VGA
steering bits. Priority for VGA mapping is constant in that the GMCH always decodes internally
mapped devices first. Internal to the GMCH, decode precedence is always given to IGD. The
GMCH always positively decodes internally mapped devices, namely the IGD. Subsequent
decoding of regions mapped to the Hub interface depends on the Legacy VGA configurations bits
(VGA Enable and MDAP). This region is also the default for SMM space.
Compatible SMRAM Address Range (0A0000h-0BFFFFh)
When compatible SMM space is enabled, SMM-mode CPU accesses to this range are routed to
physical DDR SDRAM at this address. Non-SMM-mode CPU accesses to this range are
considered to be to the video buffer area as described above. Hub interface originated cycles to
enabled SMM space are not allowed and are considered to be to the video buffer area.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
Monochrome Display Adapter (MDA) Range (0B0000h - 0B7FFFh)
Monochrome Display Adapter ranges is accessible when the Intel® 854 Chipset is strapped into
Native Graphics mode. Legacy support requires the ability to have a second graphics controller
(monochrome) in the system. Accesses in the standard VGA range are forwarded to IGD and the
Hub interface (depending on configuration bits). Since the monochrome adapter may be mapped
to anyone of these devices, the GMCH must decode cycles in the MDA range and forward them
either to IGD or to Hub interface. This capability is controlled by a VGA steering bits and the
legacy configuration bit (MDAP bit). In addition to the system memory range B0000h to B7FFFh,
the GMCH decodes IO cycles at 3B4h, 3B5h, 3B8h, 3B9h, 3BAh, and 3BFh and forwards them to
either the IGD or the Hub interface.
Expansion Area (0C0000h-0DFFFFh)
This 128-kByte ISA Expansion region is divided into eight, 16-kB segments. Each segment can be
assigned one of four Read/Write states: read-only, write-only, read/write, or disabled. Typically,
these blocks are mapped through GMCH and are subtractively decoded to ISA space. System
memory that is disabled is not remapped.
Extended System BIOS Area (0E0000h-0EFFFFh)
This 64-kByte area is divided into four, 16-kB segments. Each segment can be assigned
independent read and write attributes so it can be mapped either to main DDR SDRAM or to Hub
interface. Typically, this area is used for RAM or ROM. System memory segments that are
disabled are not remapped elsewhere.
System BIOS Area (0F0000h-0FFFFFh)
This area is a single 64-kB segment. This segment can be assigned Read and Write attributes. It is
by default (after Reset) Read/Write disabled and cycles are forwarded to Hub interface. By
manipulating the Read/Write attributes, the GMCH can "shadow" BIOS into the main DDR
SDRAM. When disabled, this segment is not remapped.
5.3
Extended System Memory Area
This system memory area covers 100000h (1 MB) to FFFFFFFFh (4 GB-1) address range and it is
divided into the following regions:
• Main system memory from 1 MB to the top of system memory.
• PCI Memory space from the top of system memory to 4 GB with two specific ranges.
• APIC Configuration Space from FEC0_0000h (4 GB-20 MB) to FECF_FFFFh (4 GB-19 MB
- 1) and FEE0_0000h (4 GB-18 MB) to FEEF_FFFFh (4 GB-17 MB-1).
• High BIOS area from 4 GB to 4 GB - 2 MB
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Intel 82854 GMCH System Address Map
5.4
Main System Memory Address Range (0010_0000h to Top
of Main Memory)
The address range from 1 MB to the top of main system memory is mapped to main DDR SDRAM
address range controlled by the GMCH. The GMCH will forward all accesses to addresses within
this range to the DDR SDRAM unless a hole in this range is created using the fixed hole as
controlled by the FDHC register. Accesses within this hole are forwarded to Hub interface.
The GMCH provides a maximum DDR SDRAM address decode space of 4-GB. The GMCH does
not remap APIC memory space. The GMCH does not limit DDR SDRAM address space in
hardware.
5.4.1
5.4.2
15 MB-16 MB Window
A hole can be created at 15 MB-16 MB as controlled by the fixed hole enable (FDHC register) in
Device 0 space. Accesses within this hole are forwarded to the Hub interface. The range of
physical DDR SDRAM disabled by opening the hole is not remapped to the top of the memory –
that physical DDR SDRAM space is not accessible. This 15 MB-16 MB hole is an optionally
enabled ISA hole. Video accelerators originally used this hole. Validation and customer SV teams
also use it for some of their test cards. That is why it is being supported. There is no inherent
BIOS request for the 15-16 hole.
Pre-allocated System Memory
Voids of physical addresses that are not accessible as general system memory and reside within
system memory address range (< TOM) are created for SMM-mode and legacy VGA graphics
compatibility. It is the responsibility of BIOS to properly initialize these regions. The number of
UMA options has been extended. Allocation is at a fixed address in terms of rigid positioning of
UMA system memory 'TOM-TSEG-UMA(size), but it is mapped at any available address by a PCI
allocation algorithm. GMADR and MMADR are requested through BARs.
The following table details the location and attributes of the regions.
Table 27.
Table 33. Pre-allocated System Memory
System Memory Segments
Attributes
Comments
00000000H - 03E7FFFFH
03E80000H - 03F7FFFFH
R/W
R/W
Available system memory 62.5 -MB
Pre-allocated Graphics VGA memory
1-MB (or 4/8/16/32- MB) when IGD is
enabled
03F80000H - 03FFFFFFH
03F80000H - 03FFFFFFH
SMM Mode Only - CPU Reads
TSEG Address Range
SMM Mode Only - CPU Reads TSEG Pre-allocated system memory
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Intel 82854 Graphics Memory Controller Hub (GMCH)
5.4.2.1
5.4.2.2
Extended SMRAM Address Range (HSEG and TSEG)
The HSEG and TSEG SMM transaction address spaces reside in this extended system memory
area.
HSEG
SMM mode CPU accesses to enabled HSEG are remapped to 000A0000h-000BFFFFh. Non-SMM
mode CPU accesses to enabled HSEG are considered invalid are terminated immediately on the
FSB. The exceptions to this rule are Non-SMM mode Write Back cycles that are remapped to
SMM space to maintain cache coherency. Hub interface originated cycles to enabled SMM space
are not allowed. Physical DDR SDRAM behind the HSEG transaction address is not remapped and
is not accessible.
5.4.2.3
TSEG
TSEG is 1-MB in size and is at the top of physical system memory. SMM mode CPU accesses to
enabled TSEG access the physical DDR SDRAM at the same address. Non-SMM mode CPU
accesses to enabled TSEG are considered invalid and are terminated immediately on the FSB. The
exceptions to this rule are Non-SMM-mode Write Back cycles that are directed to the physical
SMM space to maintain cache coherency. Hub interface originated cycles that enable SMM space
are not allowed.
The size of the SMRAM space is determined by the USMM value in the SMRAM register. When
the extended SMRAM space is enabled, non-SMM CPU accesses and all other accesses in this
range are forwarded to the Hub interface. When SMM is enabled the amount of system memory
available to the system is equal to the amount of physical DDR SDRAM minus the value in the
TSEG register.
5.4.2.4
Dynamic Video Memory Technology (DVMT)
The IGD supports DVMT in a non-graphics system memory configuration. DVMT is a mechanism
that manages system memory and the internal graphics device for optimal graphics performance.
DVMT-enabled software drivers, working with the memory arbiter and the operating system,
utilize the system memory to support 2D graphics and 3D applications. DVMT dynamically
responds to application requirements by allocating the proper amount of display and texturing
memory.
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Intel 82854 GMCH System Address Map
5.4.2.5
PCI Memory Address Range (Top of Main System Memory to 4 GB)
The address range from the top of main DDR SDRAM to 4-GB (top of physical system memory
space supported by the GMCH) is normally mapped via the Hub interface to PCI.
As an internal graphics configuration, there are two exceptions to this rule.
1. The first exception is addresses decoded to the graphics memory range. One per function in
device #2.
2. The second exception is addresses decoded to the system memory mapped range of the
Internal Graphics device. One per function in device #2. Both exception cases are forwarded to
the Internal Graphics device.
There are two sub-ranges within the PCI Memory address range defined as APIC configuration
space and High BIOS Address range. As an Internal Graphics device, the Graphics Memory range
and the Memory mapped range of the Internal Graphics device MUST NOT overlap with these two
ranges. These ranges are described in detail in the following paragraphs.
5.4.2.6
APIC Configuration Space (FEC0_0000h -FECF_FFFFh, FEE0_0000h- FEEF_FFFFh)
This range is reserved for APIC configuration space that includes the default I/O APIC
configuration space. The default Local APIC configuration space is FEE0_0000h to FEEF_0FFFh.
CPU accesses to the Local APIC configuration space do not result in external bus activity since the
Local APIC configuration space is internal to the CPU. However, an MTRR must be programmed
to make the Local APIC range uncacheable (UC). The Local APIC base address in each CPU
should be relocated to the FEC0_0000h (4 GB-20 MB) to FECF_FFFFh range so that one MTRR
can be programmed to 64-kB for the Local and I/O APICs. The I/O APIC(s) usually resides in the
ICH4-M portion of the chip-set or as a stand-alone component(s).
I/O APIC units will be located beginning at the default address FEC0_0000h. The first I/O APIC
will be located at FEC0_0000h. Each I/O APIC unit is located at FEC0_x000h where x is I/O APIC
unit number 0 through F(hex). This address range will be normally mapped to Hub interface.
The address range between the APIC configuration space and the High BIOS (FED0_0000h to
FFDF_FFFFh) is always mapped to the Hub interface.
5.4.2.7
High BIOS Area (FFE0_0000h -FFFF_FFFFh)
The top 2-MB of the Extended Memory region is reserved for System BIOS (High BIOS),
extended BIOS for PCI devices, and the A20 alias of the system BIOS. CPU begins execution
from the High BIOS after reset. This region is mapped to Hub interface so that the upper subset of
this region aliases to 16 MB to 256-kB range. The actual address space required for the BIOS is
less than 2-MB but the minimum CPU MTRR range for this region is 2-MB so that full 2-MB must
be considered.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
5.4.3
System Management Mode (SMM) Memory Range
The GMCH supports the use of main system memory as System Management RAM (SMM RAM)
enabling the use of System Management mode. The GMCH supports three SMM options:
Compatible SMRAM (C_SMRAM), High Segment (HSEG), and Top of Memory Segment
(TSEG). System Management RAM space provides a system memory area that is available for the
SMI handler's and code and data storage. This system memory resource is normally hidden from
the system OS so that the processor has immediate access to this system memory space upon entry
to SMM. The GMCH provides three SMRAM options:
• Below 1-MB option that supports compatible SMI handlers.
• Above 1-MB option that allows new SMI handlers to execute with Write-back cacheable
SMRAM.
• Above 1-MByte solutions require changes to compatible SMRAM handlers code to properly
execute above 1 MByte.
Note: Hub interface is not allowed to access the SMM space.
5.4.3.1
SMM Space Restrictions
If any of the following conditions are violated the results of SMM accesses are unpredictable and
may cause the system to hang:
• The Compatible SMM space must not be set-up as cacheable.
• High or TSEG SMM transaction address space must not overlap address space assigned to
DDR SDRAM or to any PCI devices (including Hub interface and graphics devices). This is a
BIOS responsibility.
• Both D_OPEN and D_CLOSE must not be set to 1 at the same time.
• When TSEG SMM space is enabled, the TSEG space must not be reported to the OS as
available. This is a BIOS responsibility.
5.4.3.2
SMM Space Definition
SMM space is defined by its addressed SMM space and its DDR SDRAM SMM space. The
addressed SMM space is defined as the range of bus addresses used by the CPU to access SMM
space. DDR SDRAM SMM space is defined as the range of physical DDR SDRAM locations
containing the SMM code. SMM space can be accessed at one of three transaction address ranges:
Compatible, High, and TSEG. The Compatible and TSEG SMM space is not remapped and
therefore the addressed and DDR SDRAM SMM space is the same address range. Since the High
SMM space is remapped the addressed and DDR SDRAM SMM space is a different address range.
Note that the High DDR SDRAM space is the same as the Compatible Transaction Address space.
Table 28 describes three unique address ranges:
• Compatible Transaction Address (Adr C)
• High Transaction Address (Adr H)
• TSEG Transaction Address (Adr T)
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Intel 82854 GMCH System Address Map
Table 28.
SMM Space Transaction Handling
SMM Space Enabled
Transaction Address Space (Adr)
A0000h to BFFFFh
DRAM Space (DRAM)
Compatible (C)
High (H)
A0000h to BFFFFh
A0000h to BFFFFh
0FEDA0000h to 0FEDBFFFFh
(TOM-TSEG_SZ) to TOM
TSEG (T)
(TOM-TSEG_SZ) to TOM
5.4.4
5.4.5
System Memory Shadowing
Any block of system memory that can be designated as Read-Only or Write-Only can be
"shadowed" into GMCH DDR SDRAM. Typically this is done to allow ROM code to execute
more rapidly out of main DDR SDRAM. ROM is used as a Read-Only during the copy process
while DDR SDRAM at the same time is designated Write-Only. After copying, the DDR SDRAM
is designated Read-Only so that ROM is shadowed. CPU bus transactions are routed accordingly.
I/O Address Space
The GMCH does not support the existence of any other I/O devices beside itself on the CPU bus.
The GMCH generates Hub interface or PCI bus cycles for all CPU I/O accesses that it does not
claim. Within the Host bridge the GMCH contains two internal registers in the CPU I/O space,
Configuration Address register (CONFIG_ADDRESS) and the Configuration Data register
(CONFIG_DATA). These locations are used to implement Configuration Space Access
Mechanism and as described in the Configuration register section.
The CPU allows 64 kB +3 B to be addressed within the I/O space. The GMCH propagates the CPU
I/O address without any translation on to the destination bus and therefore provides addressability
for 64 k+3 B locations. Note that the upper three locations can be accessed only during I/O address
wrap-around when CPU bus A16# address signal is asserted. A16# is asserted on the CPU bus
whenever an I/O access is made to 4 bytes from address 0FFFDh, 0FFFEh, or 0FFFFh. A16# is
also asserted when an I/O access is made to 2 bytes from address 0FFFFh.
A set of I/O accesses (other than ones used for configuration space access) is consumed by the
internal graphics device if it is enabled. The mechanisms for internal graphics IO decode and the
associated control is explained later.
The I/O accesses (other than ones used for configuration space access) are forwarded normally to
the Hub interface. The GMCH will not post I/O Write cycles to IDE.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
5.4.5.1
PCI I/O Address Mapping
The GMCH can be programmed to direct non-memory (I/O) accesses to the PCI bus interface
when CPU initiated I/O cycle addresses are within the I/O address range. This range is controlled
via the I/O Base Address (IOBASE) and I/O Limit Address (IOLIMIT) registers in GMCH
Device #1 configuration space.
Address decoding for this range is based on the following concept. The top 4 bits of the respective
I/O Base and I/O Limit registers correspond to address bits A[15:12] of an I/O address. For the
purpose of address decoding, the GMCH assumes that lower 12 address bits A[11:0] of the I/O
base are zero and that address bits A[11:0] of the I/O limit address are FFFh. This forces the I/O
address range alignment to 4-kB boundary and produces a size granularity of 4 kB.
The GMCH positively decodes I/O accesses to AGP I/O address space as defined by the following
equation:
I/O_Base_Address ≤ CPU I/O Cycle Address ≤ I/O_Limit_Address
The effective size of the range is programmed by the plug-and-play configuration software and it
depends on the size of I/O space claimed by the AGP device.
In Native Graphics mode, the GMCH also forwards accesses to the Legacy VGA I/O ranges
according to the settings in the Device #1 configuration registers BCTRL (VGA Enable) and
PCICMD1 (IOAE1), unless a second adapter (monochrome) is present on the Hub interface/PCI
(or ISA). The presence of a second graphics adapter is determined by the MDAP configuration bit.
When MDAP is set, the GMCH will decode legacy monochrome IO ranges and forward them to
the Hub interface. The IO ranges decoded for the monochrome adapter are 3B4h, 3B5h, 3B8h,
3B9h, 3Bah and 3BFh.
Note: The GMCH Device #1 I/O address range registers defined above are used for all I/O space
allocation for any devices requiring such a window on PCI. These devices would include the AGP
device, PCI-66MHz/3.3V agents, and multifunctional AGP devices where one or more functions
are implemented as PCI devices.
The PCICMD1 register can disable the routing of I/O cycles to PCI.
5.4.6
GMCH Decode Rules and Cross-Bridge Address Mapping
The address map described above applies globally to accesses arriving on any of the three
interfaces (e.g., Host bus, IGD, and Hub interface).
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Intel 82854 GMCH System Address Map
5.4.7
Hub Interface Decode Rules
The GMCH accepts accesses from Hub interface to the following address ranges:
• All Memory Read and Write accesses to Main DDR SDRAM including PAM region (except
SMM space)
• Memory writes to VGA range (Native Graphics Mode only)
All Memory Reads from the Hub interface A that are targeted > 4-GB system memory range will
be terminated with Master Abort completion, and all Memory Writes (>4-GB) from the Hub
interface will be ignored.
Hub interface system memory accesses that fall elsewhere within the system memory range are
considered invalid and will be remapped to system memory address 0h, snooped on the Host Bus,
and dispatched to DDR SDRAM. Reads will return all 1's with Master Abort completion. Writes
will have BE's deasserted and will terminate with Master Abort if completion is required. I/O
cycles will not be accepted. They are terminated with Master Abort completion packets.
5.4.7.1
Hub Interface Accesses to GMCH that Cross Device Boundaries
Hub interface accesses are limited to 256 B (Bytes) but have no restrictions on crossing address
boundaries. A single Hub interface request may therefore span device boundaries (DDR SDRAM)
or cross from valid addresses to invalid addresses (or visa versa). The GMCH does not support
transactions that cross device boundaries. For Reads and for Writes requiring completion, the
GMCH will provide separate completion status for each naturally aligned 32-B or 64-B block. If
the starting address of a transaction hits a valid address, the portion of a request that hits that target
device (DDR SDRAM) will complete normally. The remaining portion of the access that crosses a
device boundary (targets a different device than that of the starting address) or hits an invalid
address will be remapped to system memory address 0h, snooped on the Host Bus, and dispatched
to DDR SDRAM. Reads will return all 1's with Master Abort completion. Writes will have BE's
(Byte Enable) deasserted and will terminate with Master Abort if completion is required.
If the starting address of a transaction hits an invalid address the entire transaction will be
remapped to system memory address 0h, snooped on the Host Bus, and dispatched to DDR
SDRAM. Reads will return all 1's with Master Abort completion. Writes will have BE's deasserted
and will terminate with Master Abort if completion is required.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
5.4.7.2
Interface Decode Rules
Cycles Initiated Using PCI Protocol
The GMCH does not support any PCI access targeting Hub interface. The GMCH will claim PCI
initiated memory read and write transactions decoded to the main DDR SDRAM range. All other
memory read and write requests will be master-aborted by the PCI initiator as a consequence of
GMCH not responding to a transaction.
Under certain conditions, the GMCH restricts access to the DOS Compatibility ranges governed by
the PAM registers by distinguishing access type and destination bus. The GMCH accepts PCI
write transactions to the compatibility ranges if the PAM designates DDR SDRAM as writeable. If
accesses to a range are not write enabled by the PAM, the GMCH does not respond and the cycle
will result in a master-abort. The GMCH accepts PCI read transactions to the compatibility ranges
if the PAM designates DDR SDRAM as readable. If accesses to a range are not read enabled by
the PAM, the GMCH does not respond and the cycle will result in a master-abort.
If agent on PCI issues an I/O or PCI Special Cycle transaction, the GMCH will not respond and
cycle will result in a master-abort. The GMCH will accept PCI configuration cycles to the internal
GMCH devices as part of the PCI configuration/co-pilot mode mechanism.
Accesses to GMCH that Cross Device Boundaries
For FRAME# accesses, when a PCI master gets disconnected it will resume at the new address
which allows the cycle to be routed to or claimed by the new target. Therefore accesses should be
disconnected by the target on potential device boundaries. The GMCH will disconnect PCI
transactions on 4-kB boundaries.
SBA accesses are limited to 256 bytes and must hit DDR SDRAM. Accesses are dispatched to
DDR SDRAM on naturally aligned 32 byte block boundaries. The portion of the request that hits a
valid address will complete normally. The portion of a read access that hits an invalid address will
be remapped to address 0h, return data from address 0h, and set the IAAF error flag. The portion of
a write access that hits an invalid address will be remapped to memory address 0h with BE's
deasserted (effectively dropped "on the floor") and set the IAAF error flag.
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Functional Description
6.0
Functional Description
6.1
Host Interface Overview
The GMCH front side bus uses source synchronous transfer for the address and data signals. The
address signals are double pumped and two addresses can be generated every bus clock. At
100-MHz bus frequency, the two address signals run at 200 MHz for a maximum address queue
rate of 50-M addresses/sec. The data is quad pumped and an entire 64-B cache line can be
transferred in two bus clocks. At 100-MHz/133MHz bus frequency, the data signals run at
400 MHz for a maximum bandwidth of 3.2/4.3GB/s. The GMCH supports a 8-deep IOQ (In-
Order-Queue) using the Intel Celeron M processor, or Genuine Intel® Processor.
6.2
Dynamic Bus Inversion
The GMCH supports dynamic bus inversion (DBI) when driving and receiving data from the Host
Bus. DBI limits the number of data signals that are driven to a low voltage on each quad pumped
data phase. This decreases the power consumption of the GMCH. DINV[3:0]# indicates if the
corresponding 16 bits of data are inverted on the bus for each quad pumped data phase:
Table 29.
Relation of DBI Bits to Data Bits
DINV[3:0]
Data Bits
DINV[0]#
DINV[1]#
DINV[2]#
DINV[3]#
HD[15:0]#
HD[31:16]#
HD[47:32]#
HD[63:48]#
Whenever the CPU or the GMCH drives data, each 16-bit segment is analyzed. If more than eight
of the 16 signals would normally be driven low on the bus the corresponding DINV# signal will be
asserted and the data will be inverted prior to being driven on the bus. Whenever the CPU or the
GMCH receives data it monitors DINV[3:0]# to determine if the corresponding data segment
should be inverted.
6.2.1
System Bus Interrupt Delivery
The Intel Celeron M processor support system bus interrupt delivery. It does not support the APIC
serial bus interrupt delivery mechanism. Interrupt related messages are encoded on the system bus
as Interrupt Message transactions. System bus interrupts may originate from the processor on the
system bus, or from a downstream device on the Hub interface.
In a GMCH platform, the ICH4-M contains IOxAPICs and its interrupts are generated as upstream
Hub interface Memory Writes. Furthermore, PCI 2.2 defines MSI's (Message Signaled Interrupts)
that are also in the form of Memory Writes. A PCI 2.2 device may generate an interrupt as an MSI
cycle on its PCI bus instead of asserting a hardware signal to the IOxAPIC. The MSI may be
directed to the IOxAPIC, which in turn generates an interrupt as an upstream Hub interface
memory write. Alternatively the MSI may be directed directly to the system bus. The target of an
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Intel 82854 Graphics Memory Controller Hub (GMCH)
MSI is dependent on the address of the interrupt Memory Write. The GMCH forwards inbound
Hub interface memory writes to address 0FEEx_xxxxh, to the system bus as Interrupt Message
transactions.
6.2.2
Upstream Interrupt Messages
The GMCH accepts message based interrupts from its Hub interface and forwards them to the
system bus as Interrupt Message transactions. The Interrupt Messages presented to the GMCH are
in the form of Memory Writes to address 0FEEx_xxxxh. At the Hub interface, the Memory Write
Interrupt Message is treated like any other Memory Write; it is either posted into the inbound data
buffer (if space is available) or retried (if data buffer space is not immediately available). Once
posted, the Memory Write from the Hub interface, to address 0FEEx_xxxxh, is decoded as a cycle
that needs to be propagated by the GMCH to the front side bus as an Interrupt Message transaction.
6.3
System Memory Interface
6.3.1
DDR SDRAM Interface Overview
The GMCH supports DDR SDRAM at 200/266-MHz and includes the following support:
• Up to 1 GB of PC2100/PC2700 DDR SDRAM
• Maximum of two DDR DIMMs, single-sided and/or double-sided
The 2-bank select lines SBA[1:0] and the 13 Address lines SMA[12:0] allow the GMCH to support
64-bit wide DDR DIMMs using 128-Mb, 256-Mb, and 512-Mb DDR SDRAM technology. While
address lines SMA[9:0] determine the starting address for a burst, burst length can only be 4. Four
chip selects SCS[3:0]# lines allow a maximum of two rows of single-sided DDR SDRAM DIMMs
and four rows of double-sided DDR SDRAM DIMMs.
The GMCH main system memory controller targets CAS latencies of 2 and 2.5 for DDR SDRAM.
The GMCH provides refresh functionality with a programmable rate (normal DDR SDRAM rate is
1 refresh/15.6 µs). For write operations of less than a full cache line, GMCH will perform a cache-
line read and into the write buffer and perform byte-wise write-merging in the write buffer.
6.3.2
System Memory Organization and Configuration
6.3.2.1
Configuration Mechanism for DDR DIMMs
Detection of the type of DDR SDRAM installed on the DDR DIMM is supported via Serial
Presence Detect mechanism as defined in the JEDEC 200-pin DDR DIMM specification.
Before any cycles to the system memory interface can be supported, the GMCH DDR SDRAM
registers must be initialized. The GMCH must be configured for operation with the installed
system memory types. Detection of system memory type and size is done via the System
Management Bus (SMB) interface on the ICH4-M. This two-wire bus is used to extract the DDR
SDRAM type and size information from the Serial Presence Detect port on the DDR SDRAM
DDR DIMMs. DDR SDRAM DIMMs contain a 5-pin Serial Presence Detect interface, including
SCL (serial clock), SDA (serial data) and SA[2:0]. Devices on the SMBus have a 7-bit address.
For the DDR SDRAM DIMMs, the upper four bits are fixed at 1010b. The lower three bits are
strapped on the SA[2:0] pins. SCL and SDA are connected directly to the System Management bus
on the ICH4-M. Thus data is read from the Serial Presence Detect port on the DDR DIMMs via a
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series of I/O cycles to the south bridge. The BIOS needs to determine the size and type of system
memory used for each of the rows of system memory in order to properly configure the GMCH
system memory interface.
For SMBus Configuration and Access of the Serial Presence Detect Ports, refer to the Intel®
82801DBM I/O Controller Hub 4 (ICH4-M) Datasheet (252337) for more detail.
6.3.2.2
System Memory Register Programming
This section provides an overview of how the required information for programming the DDR
SDRAM registers is obtained from the Serial Presence Detect ports on the DDR DIMMs. The
Serial Presence Detect ports are used to determine Refresh Rate, MA and MD Buffer Strength, row
a subset of the data available through the on board Serial Presence Detect ROM on each DDR
DIMM.
Table 30.
Data Bytes on DDR DIMM Used for Programming DRAM Registers
Byte
Function
2
System Memory Type (DDR SDRAM)
Number of row addresses, not counting Bank Addresses
Number of Column Addresses
Number of DIMM banks
3
4
5
12
17
Refresh Rate/Type
Number Banks on each Device
provide enough data for programming the GMCH DDR SDRAM registers.
6.3.3
DDR SDRAM Performance Description
The overall system memory performance is controlled by the DDR SDRAM timing register,
pipelining depth used in GMCH, system memory speed grade and the type of DDR SDRAM used
in the system. Besides this, the exact performance in a system is also dependent on the total system
memory supported, external buffering and system memory array layout. The most important
contribution to overall performance by the system memory controller is to minimize the latency
required to initiate and complete requests to system memory, and to support the highest possible
bandwidth (full streaming, quick turn-arounds). One measure of performance is the total flight
time to complete a cache line request. A true discussion of performance really involves the entire
chipset, not just the system memory controller.
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6.4
Integrated Graphics Overview
®
The Intel 82854 GMCH provides a highly integrated graphics accelerator and PCI set while
allowing a flexible Integrated System Graphics solution.
®
Figure 7.
Intel 82854 GMCH Graphics Block Diagram (Native Graphic Mode only)
DDR/SDRAM
Memory Control
DAC
Overlay
Video Engine
(MPEG2 Decode)
Cntl
Mux
Port
Alpha
Blend/
Gamma/
CRC
2D Engine
DVOB
Primary
Display
3D Engine
Instr./
Data
Setup/Transform
Scan Conversion
Texture Engine
Raster Engine
DVOC
Display C
2nd Overlay
High bandwidth access to data is provided through the system memory port. The GMCH uses a
tiling architecture to minimize page miss latencies and thus maximize effective rendering
bandwidth.
6.4.1
3D/2D Instruction Processing
The GMCH contains an extensive set of instructions that control various functions including 3D
rendering, BLT operations, display, MPEG decode acceleration, and overlay. The 3D instructions
set 3D pipeline states and control the processing functions. The 2D instructions provide an efficient
method for invoking BLT operations.
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6.4.2
3D Engine
The 3D engine of the GMCH has been designed with a deeply pipelined architecture, where
performance is maximized by allowing each stage of the pipeline to simultaneously operate on
different primitives or portions of the same primitive. The GMCH supports the following:
• Perspective-corrected Texture mapping
• Multitexturing
• Embossed and Dot-Product Bump mapping
• Cubic Environment Maps
• Bilinear, Trilinear, and Anisotropic MIP map filtering
• Gouraud shading and Flat shading
• Alpha-blending
• Per-Vertex and per- pixel fog
• Z/W buffering
These features are independently controlled via a set of 3D instructions. The 3D pipeline
subsystem performs the 3D rendering acceleration. The main blocks of the pipeline are the Setup
Engine, Scan Converter, Texture Pipeline, and Raster Pipeline. A typical programming sequence
would be to send instructions to set the state of the pipeline followed by rendering instructions
containing 3D primitive vertex data.
6.4.2.1
Setup Engine
The GMCH 3D setup engine takes the input data associated with each vertex of a 3D primitive and
computes the various parameters required for scan conversion. In formatting this data, the GMCH
maintains sub-pixel accuracy. The per-vertex data is converted into gradients that can be used to
interpolate the data at any pixel within a polygon (colors, alpha, Z or W depth, fog, and texture
coordinates). The pixels covered by a polygon are identified and per-pixel texture addresses are
calculated.
6.4.2.2
6.4.2.3
6.4.2.4
Viewport Transform and Perspective Divide
A 3D-geometry pipeline typically involves transformation of vertices from model space to clipping
space followed by clip test and clipping. Lighting can be performed during the transformation or at
any other point in the pipeline. After clipping, the next stage involves perspective divide followed
by transformation to the viewport or screen space. The GMCH can support viewport transform and
perspective divide portion of the 3D geometry pipeline in hardware.
3D Primitives and Data Formats Support
The 3D primitives rendered by the GMCH are points, lines, discrete triangles, line strips, triangle
strips, triangle fans, and polygons. In addition to this, the GMCH supports DirectX's* Flexible
Vertex Format* (FVF), which enables the application to specify a variable length parameter list,
obviating the need for sending unused information to the hardware. Strips, Fans, and Indexed
Vertices as well as FVF improves delivered vertex rate to the setup engine significantly.
Pixel Accurate Fast Scissoring and Clipping Operation
The GMCH supports clipping to a scissoring rectangle within the drawing window. The GMCH
clipping and scissoring in hardware reduce the need for software to process polygons, and thus
improves performance. During the setup stage, the GMCH clips polygons to the drawing window.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
The scissor rectangle accelerates the clipping process by allowing the driver to clip to a bigger
region than the hardware renders to. The scissor rectangle is pixel accurate, and independent of line
and point width. The GMCH supports a single scissor box rectangle.
6.4.2.5
Backface Culling
As part of the setup, the GMCH can discard polygons from further processing, if they are either
facing away from or towards the user's viewpoint. This operation, referred to as Back Face Culling
is accomplished based on the clockwise or counter-clockwise orientation of the vertices on a
primitive. This can be enabled or disabled by the driver.
6.4.2.6
6.4.2.7
Scan Converter
The Scan Converter takes the vertex and edge information identifies all pixels that are affected by
features being rendered. It works on a per-polygon basis, and one polygon may be entering the
pipeline while calculations finish on another.
Texture Engine
The GMCH allows an image pattern or video to be placed on the surface of a 3D polygon. The
texture engine performs texture color or chromakey matching texture filtering (anisotropic,
trilinear, and bilinear) and YUV to RGB conversion.
As texture sizes increase beyond the bounds of graphics memory, executing textures from graphics
memory becomes impractical. Every rendering pass would require copying each and every texture
in a scene from system memory to graphics memory, then using the texture, and finally overwriting
the local memory copy of the texture by copying the next texture into graphics memory. The
GMCH, using Intel's Direct Memory Execution model, simplifies this process by rendering each
scene using the texture located in system memory. The GMCH includes a cache controller to avoid
frequent memory fetches of recently used texture data.
6.4.2.8
6.4.2.9
Perspective Correct Texture Support
A textured polygon is generated by mapping a 2D texture pattern onto each pixel of the polygon. A
texture map is like wallpaper pasted onto the polygon. Since polygons are rendered in perspective,
it is important that texture be mapped in perspective as well. Without perspective correction,
texture is distorted when an object recedes into the distance. Perspective correction involves a
compute-intensive "per-pixel-divide" operation on each pixel. Perspective correction is necessary
for realistic 3D graphics.
Texture Decompression
As the textures' average size gets larger with higher color depth and multiple textures become the
norm, it becomes increasingly important to provide support for compressed textures.
DirectX* supports Texture Compression/Decompression to reduce the bandwidth required to
deliver textures. The GMCH supports several compressed texture formats (DirectX: DXT1, DXT2,
DXT3, DXT4, DXT5) and OpenGL FXT1 formats.
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6.4.2.10
Texture Chromakey
Chromakey is a method for removing a specific color or range of colors from a texture map before
it is applied to an object. For nearest texture filter modes, removing a color simply makes those
portions of the object transparent (the previous contents of the back buffer show through). For
linear texture filtering modes, the texture filter is modified if only the non-nearest neighbor texels
match the key (range).
Chromakeying can be performed for both paletted and non-paletted textures, and removes texels
that fall within a specified color range. The Chromakey mode refers to testing the ARGB or YUV
components to see if they fall between high and low state variable values. If the color of a texel
contribution is in this range and chromakey is enabled, then this contribution is removed from the
resulting pixel color.
6.4.2.11
Anti-Aliasing
Aliasing is one of the artifacts that degrade image quality. In its simplest manifestation, aliasing
causes the jagged staircase effects on sloped lines and polygon edges. Another artifact is the moiré
patterns, which occur as a result of the fact that there is very small number of pixels available on
screen to contain the data of a high-resolution texture map.
Full scene anti-aliasing uses super-sampling, which means that the image is rendered internally at a
higher resolution than it is displayed on screen. The GMCH renders internally at 1600x1200, reads
the image as a texture, and finally down-samples (via a Bilinear filter) to the screen resolution of
640x480 and 800x600. Full scene anti-aliasing removes jaggies at the edges.
6.4.2.12
Texture Map Filtering
Many texture-mapping modes are supported. Perspective correct mapping is always performed.
As the map is fitted across the polygon, the map can be tiled, mirrored in either the U or V
directions, or mapped up to the end of the texture and no longer placed on the object (this is known
as clamp mode). The way a texture is combined with other object attributes is also definable.
The GMCH supports up to 12 Levels-of-Detail (LODs) ranging in size from 2048x2048 to 1x1
texels. (A texel is defined as a texture map element.) Included in the texture processor is a texture
cache, which provides efficient MIP-mapping.
The GMCH supports seven types of texture filtering:
• Nearest (also known as Point filtering): Texel with coordinates nearest to the desired pixel is
used. (This is used if only one LOD is present.)
• Linear (also known as Bilinear filtering): A weighted average of a 2x2 area of texels
surrounding the desired pixel is used. (This is used if only one LOD is present.)
• Nearest MIP Nearest (also known as Point filtering): This is used if many LODs are present.
The nearest LOD is chosen and the texel with coordinates nearest to the desired pixel are used.
• Linear MIP Nearest (Bilinear MIP mapping): This is used if many LODs are present. The
nearest LOD is chosen and a weighted average of a 2x2 area of texels surrounding the desired
pixel is used (four texels). This is also referred to as Bilinear MIP Mapping.
• Nearest MIP Linear (Point MIP mapping): This is used if many LODs are present. Two
appropriate LODs are selected and within each LOD the texel with coordinates nearest to the
desired pixel are selected. The Final texture value is generated by linear interpolation between
the two texels selected from each of the MIP Maps.
• Linear MIP Linear (Trilinear MIP mapping): This is used if many LODs are present. Two
appropriate LODs are selected and a weighted average of a 2x2 area of texels surrounding the
desired pixel in each MIP Map is generated (four texels per MIP Map). The Final texture
value is generated by linear interpolation between the two texels generated for each of the MIP
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Intel 82854 Graphics Memory Controller Hub (GMCH)
Maps. Trilinear MIP Mapping is used minimize the visibility of LOD transitions across the
polygon.
• Anisotropic MIP Nearest (Anisotropic filtering): This filter can be used when textured object
pixels map back to significantly non-square regions of the texture (e.g., when the texture is
scaled in one screen direction than the other screen direction).
Both DirectX and OpenGL (Rev.1.1) allow support for all these filtering modes.
6.4.2.13
Multiple Texture Composition
The GMCH also performs multiple texture composition. This allows the combination of two or
greater MIP maps to produce a new one with new LODs and texture attributes in a single or
iterated pass. The setup engine supports up to four texture map coordinates in as single pass. The
GMCH allows up to two Bilinear MIP Maps or a single Trilinear MIP Map to be composited in a
single pass. Greater than two Bilinear MIP Maps or more than one Trilinear MIP Map would
require multiple passes. The actual blending or composition of the MIP Maps is done in the raster
engine. The texture engine provides the required texels including blending information.
Flexible vertex format support allows multi-texturing because it makes it possible to pass more
than one texture in the vertex structure.
6.4.2.14
Cubic Environment Mapping
Environment maps allow applications to render scenes with complex lighting and reflections while
significantly decreasing CPU load. There are several methods to generate environment maps such
as spherical, circular and cubic. The GMCH supports cubic reflection mapping over spherical and
circular since it is the best choice to provide real-time environment mapping for complex lighting
and reflections.
Cubic Mapping supports a texture map for each of the 6 cube faces. These can be generated by
pointing a camera with a 90-degree field-of-view in the appropriate direction. Per-vertex vectors
(normal, reflection or refraction) are interpolated across the polygon and the intersection of these
vectors with the cube texture faces are calculated. Texel values are then read from the intersection
point on the appropriate face and filtered accordingly.
6.4.2.15
Bump Mapping
The GMCH only supports embossed and dot product bump mapping, not environment bump
mapping.
6.4.3
Raster Engine
The Raster engine is where the color data such as fogging, specular RGB, texture map blending,
etc. is processed. The final color of the pixel is calculated and the RGB value is combined with the
corresponding components resulting from the Texture engine. These textured pixels are modified
by the specular and fog parameters. These specular highlighted, fogged, textured pixels are color
blended with the existing values in the frame buffer. In parallel, stencil, alpha, and depth buffer
tests are conducted which will determine whether the Frame and Depth buffers will be updated
with the new pixel values.
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6.4.3.1
6.4.3.2
Texture Map Blending
Multiple textures can be blended together in an iterative process and applied to a primitive. The
GMCH allows up to four distinct or shared texture coordinates and texture maps to be specified
onto the same polygon. Also, the GMCH supports a texture coordinate set to access multiple
texture maps. State variables in multiple textures are bound to texture coordinates, texture map or
texture blending.
Combining Intrinsic and Specular Color Components
The GMCH allows an independently specified and interpolated specular RGB attribute to be added
to the post-texture blended pixel color. This feature provides a full RGB specular highlight to be
applied to a textured surface, permitting a high quality reflective colored lighting effect not
available in devices which apply texture after the lighting components have been combined. If the
specular-add state variable is disabled, only the resultant colors from the map blending are used. If
this state variable is enabled, the specular RGB color is added to the RGB values from the output of
the map blending.
6.4.3.3
Color Shading Modes
The Raster engine supports the Flat and Gouraud shading modes. These shading modes are
programmed by the appropriate state variables issued through the command stream.
• Flat shading is performed by smoothly interpolating the vertex intrinsic color components
(Red, Green, Blue), Specular (R, G, B), Fog, and Alpha to the pixel, where each vertex color
has the same value. The setup engine substitutes one of the vertex's attribute values for the
other two vertices attribute values thereby creating the correct flat shading terms. This
condition is set up by the appropriate state variables issued prior to rendering the primitive.
• Gouraud shading is performed by smoothly interpolating the vertex intrinsic color components
(Red, Green, Blue). Specular (RGB), Fog, and Alpha to the pixel, where each vertex color has
a different value.
6.4.3.4
6.4.3.5
Color Dithering
Color Dithering in the GMCH helps to hide color quantization errors for 16-bit color buffers. Color
Dithering takes advantage of the human eye's propensity to average the colors in a small area. Input
color, alpha, and fog components are converted from 8-bit components to 5-bit or 6-bit component
by dithering. Dithering is performed on blended textured pixels. In 32-bit mode, dithering is not
performed.
Vertex and Per Pixel Fogging
Fogging is used to create atmospheric effects such as low visibility conditions in flight simulator-
type games. It adds another level of realism to computer-generated scenes. Fog can be used for
depth cueing or hiding distant objects. With fog, distant objects can be rendered with fewer details
(less polygons), thereby improving the rendering speed or frame rate. Fog is simulated by
attenuating the color of an object with the fog color as a function of distance, and the greater the
distance, the higher the density (lower visibility for distant objects). There are two ways to
implement the fogging technique: per-vertex (linear) fogging and per-pixel (non-linear) fogging.
The per-vertex method interpolates the fog value at the vertices of a polygon to determine the fog
factor at each pixel within the polygon. This method provides realistic fogging as long as the
polygons are small. With large polygons (such as a ground plane depicting an airport runway), the
per-vertex technique results in unnatural fogging.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
The GMCH supports both types of fog operations, vertex and per pixel. If fog is disabled, the
incoming color intensities are passed unchanged to the destination blend unit. If fog is enabled, the
incoming pixel color is blended with the fog color based on a fog coefficient on a per pixel basis.
6.4.3.6
Alpha Blending
Alpha blending in the GMCH adds the material property of transparency or opacity to an object.
Alpha blending combines a source pixel color and alpha component with a destination pixel color
and alpha component. For example, this is so that a glass surface on top (source) of a red surface
(destination) would allow much of the red base color to show through.
Blending allows the source and destination color values to be multiplied by programmable factors
and then combined via a programmable blend function. The combined and independent selection
of factors and blend functions for color and alpha is supported.
6.4.3.7
Color Buffer Formats: (Destination Alpha)
The Raster engine supports 8-bit, 16-bit, and 32-bit Color Buffer formats. The 8-bit format is used
to support planar YUV4:2:0 format, which is used only in Motion Compensation and Arithmetic
Stretch format. The bit format of Color and Z is allowed to mix.
The GMCH can support an 8-bit destination alpha in 32-bit mode. Destination alpha is supported in
16-bit mode in 1:5:5:5 or 4:4:4:4 format. The GMCH does not support general 3D rendering to 8-
bit surfaces. 8-bit destinations are supported for operations on planar YUV surfaces (for example,
stretch BLTs) where each 8-bit color component is written in a separate pass. The GMCH also
supports a mode where both U and V planar surfaces can be operated on simultaneously.
The frame buffer of the GMCH contains at least two hardware buffers - the Front Buffer (display
buffer) and the Back Buffer (rendering buffer). While the back buffer may actually coincide with
(or be part of) the visible display surface, a separate (screen or window-sized) back buffer is
typically used to permit double-buffered drawing. That is, the image being drawn is not visible
until the scene is complete and the back buffer made visible or copied to the front buffer via a 2D
BLT operation. Rendering to one buffer and displaying from the other buffer removes image
tearing artifacts. Additionally, more than two back buffers (for example, triple-buffering) can be
supported.
6.4.3.8
Depth Buffer
The Raster Engine is able to read and write from this buffer and use the data in per fragment
operations that determine resultant color and depth value of the pixel for the fragment are to be
updated or not.
Typical applications for entertainment or visual simulations with exterior scenes require far/near
ratios of 1000 to 10000. At 1000, 98% of the range is spent on the first 2% of the depth. This can
cause hidden surface artifacts in distant objects, especially when using 16-bit depth buffers. A 24-
bit Z-buffer provides 16 million Z-values as opposed to only 64 k with a 16-bit Z-buffer. With
lower Z-resolution, two distant overlapping objects may be assigned the same Z-value. As a result,
the rendering hardware may have a problem resolving the order of the objects, and the object in the
back may appear through the object in the front.
By contrast, when w (or eye-relative z) is used, the buffer bits can be more evenly allocated
between the near and far clip planes in world space. The key benefit is that the ratio of far and near
is no longer an issue, and allows applications to support a maximum range of miles, yet still get
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reasonably accurate depth buffering within inches of the eye point. The selection of depth buffer
size is relatively independent of the color buffer. A 16-bit Z/W or 24-bit Z/W buffer can be selected
with a 16-bit color buffer. Z buffer is not supported in 8-bit mode.
6.4.3.9
Stencil Buffer
The Raster engine provides 8-bit stencil buffer storage in 32-bit mode and the ability to perform
stencil testing. Stencil testing controls 3D drawing on a per pixel basis and conditionally eliminates
a pixel on the outcome of a comparison between a stencil reference value and the value in the
stencil buffer at the location of the source pixel being processed. They are typically used in
multipass algorithms to achieve special effects, such as decals, outlining, shadows, and
constructive solid geometry rendering.
One of three possible stencil operations is performed when stencil testing is enabled. The stencil
operation specifies how the stencil buffer is modified when a fragment passes or fails the stencil
test. The selection of the stencil operation to be performed is based upon the result of the stencil
test and the depth test. A stencil write mask is also included that controls the writing of particular
bits into the stencil buffer. It selects between the destination value and the updated value on a per-
bit basis. The mask is 8-bit wide.
6.4.3.10
Projective Textures
The GMCH supports two simultaneous projective textures at full rate processing. These textures
require three floating-point texture coordinates to be included in the FVF format. Projective
textures enable special effects such as projecting spot light textures obliquely onto walls, and so on.
6.4.4
2D Engine
The GMCH provides an extensive set of 2D instructions and 2D HW acceleration for block
transfers of data (BLTs). The BLT engine provides the ability to copy a source block of data to a
destination and perform operations (for example, ROP1, ROP2, and ROP3) on the data using a
pattern, and/or another destination. The Stretch BLT engine is used to move source data to a
destination that need not be the same size, with source transparency. Performing these common
tasks in hardware reduces CPU load, and thus improves performance.
6.4.4.1
256-Bit Pattern Fill and BLT Engine
Use of this BLT engine accelerates the Graphical User Interface (GUI) of Microsoft* Windows*.
The GMCH BLT Engine provides hardware acceleration of block transfers of pixel data for many
common Windows operations. The term BLT refers to a block transfer of pixel data between
system memory locations. The BLT engine can be used for the following:
• Move rectangular blocks of data between system memory locations
• Data alignment
• Perform logical operations (raster ops)
The rectangular block of data does not change as it is transferred between system memory
locations. Data to be transferred can consist of regions of system memory, patterns, or solid color
fills. A pattern will always be 8x8 pixels wide and may be 8-bits, 16-bits, or 32-bits per pixel.
The GMCH BLT engine has the ability to expand monochrome data into a color depth of 8 bits, 16
bits, or 32 bits. BLTs can be either opaque or transparent. Opaque transfers, move the data
specified to the destination. Transparent transfers compare destination color to source color and
write according to the mode of transparency selected.
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Data is horizontally and vertically aligned at the destination. If the destination for the BLT
overlaps with the source system memory location, the GMCH can specify which area in system
memory to begin the BLT transfer. Hardware is included for all 256 raster operations (source,
pattern, and destination) defined by Microsoft, including transparent BLT.
The GMCH has instructions to invoke BLT operations, permitting software to set up instruction
buffers and use batch processing as described in the Instruction Processing section. The GMCH
can perform hardware clipping during BLTs.
6.4.4.2
Alpha Stretch BLT
The stretch BLT function can stretch source data in the X and Y directions to a destination larger or
smaller than the source. Stretch BLT functionality expands a region of system memory into a
larger or smaller region using replication and interpolation. The stretch BLT function also provides
format conversion and data alignment.
6.4.5
Planes and Engines
The GMCH display can be functionally delineated into planes and engines (pipes and ports). A
plane consists of rectangular shaped image that has characteristics such as source, size, position,
method, and format. These planes get attached to source surfaces, which are rectangular system
memory surfaces with a similar set of characteristics. They are also associated with a particular
destination pipe.
A pipe consists of a set of planes that will be combined with a timing generator. A port is the
destination for the result of the pipe. The GMCH supports one Analog Output Port and two DVO
ports. In conclusion, planes are associated with pipes and pipes are associated with ports.
6.4.5.1
Dual Pipe Independent Display Functionality (Native Graphic Mode only)
The display consists of two display pipes, A and B. Pipes have a set of planes that are assigned to
them as sources. The analog display port may only use Pipe A or Pipe B, the DVO B or C ports
may use either Pipe A or Pipe B. This limits the resolutions available on a digital display when an
analog CRT is active.
Table 31.
Dual Display Usage Model (Native Graphic Mode only)
Display Pipe A
Display Pipe B
DVO B or C or Both
CRT
CRT
DVO B or C or Both
DVO C
DVO B
6.4.6
Hardware Cursor Plane (Native Graphic Mode only)
The GMCH supports two hardware cursors. The cursor plane is one of the simplest display planes.
With a few exceptions, has a fixed size of 64 x 64 and a fixed Z-order (top). In legacy modes,
cursor can cause the display data below it to be inverted. In the alpha blend mode, true color cursor
data can be alpha blended into the display stream. It can be assigned to either display pipe A or
display pipe B and dynamically flipped from one to the other when both are running.
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6.4.6.1
Cursor Color Formats
Color data can be in an indexed format or a true color format. Indexed data uses the entries in the
four-entry cursor palette to convert the two-bit index to a true color format before being passed to
the blenders. The index can optionally specify that a cursor pixel be transparent or cause an
inversion of the pixel value below it or one of two colors from the cursor palette. Blending of YUV
or RGB data is only supported with planes that have data of the same format.
6.4.6.2
6.4.6.3
Popup Plane (Second Cursor)
The popup plane is used for control functions in mobile applications. Only the hardware cursor has
a higher Z-order precedence over the hardware icon. In standard modes (non-VGA) either cursor A
or cursor B can be used as a Popup Icon. For VGA modes, 32-bpp data format is not supported.
Popup Color Formats
Source color data for the popup is in an indexed format. Indexed data uses the entries in the four-
entry cursor palette to convert the two-bit index to a true color format before being passed to the
blenders. Blending of color data is only supported with data of the same format.
6.4.7
Overlay Plane
The overlay engine provides a method of merging either video capture data (from an external
Video Capture device) or data delivered by the CPU, with the graphics data on the screen.
6.4.7.1
Multiple Overlays (Display C)
A single overlay plane and scalar is implemented. This overlay plane can be connected to the
primary display, secondary display or in bypass mode. In the default mode, it appears on the
primary display. The overlay may be displayed in a multi-monitor scenario for single-pipe
simultaneous displays only. Picture-in-Picture feature is supported via software through the
arithmetic stretch BLT.
6.4.7.2
Source/Destination Color/Chromakeying
Overlay source/destination chromakeying enables blending of the overlay with the underlying
graphics background. Destination color-/chromakeying can be used to handle occluded portions of
the overlay window on a pixel-by-pixel basis that is actually an underlay. Destination color keying
supports a specific color (8-bit or 15-bit) mode as well as 32-bit alpha blending.
Source color/chromakeying is used to handle transparency based on the overlay window on a
pixel-by-pixel basis. This is used when "blue screening" an image to overlay the image on a new
background later.
6.4.7.3
6.4.7.4
Gamma Correction
To compensate for overlay color intensity loss, the overlay engine supports independent gamma
correction. This allows the overlay data to be converted to linear data or corrected for the display
device when not blending.
YUV to RGB Conversion
The format conversion can be bypassed in the case of RGB source data.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
6.4.7.5
6.4.7.6
Color Control
Color control provides a method of changing the color characteristics of the pixel data. It is applied
to the data while in YUV format and uses input parameters such as brightness, saturation, hue (tint)
and contrast. This feature is supplied for the overlay only and works in YUV formats only.
Dynamic Bob and Weave
Interlaced data that originates from a video camera creates two fields that are temporally offset by
1/60 of a second. There are several schemes to de-interlace the video stream: line replication,
vertical filtering, field merging, and vertical temporal filtering. Field merging takes lines from the
previous field and inserts them into the current field to construct the frame - this is known as
weaving. This is the best solution for images with little motion; however, showing a frame that
consists of the two fields will have serration or feathering of moving edges when there is motion in
the scene. Vertical filtering or "Bob" interpolates adjacent lines rather replicating the nearest
neighbor. This is the best solution for images with motion however, it will have reduced spatial
resolution in areas that have no motion and introduce jaggies. In absence of any other de-
interlacing, these form the baseline and are supported by the GMCH.
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Functional Description
6.4.8
Video Functionality
The GMCH supports MPEG-2 decoding hardware, sub-picture support and DTV.
6.4.8.1
MPEG-2 Decoding
The GMCH MPEG2 Decoding supports Hardware Motion Compensation (HWMC). The GMCH
can accelerate video decoding for the following video coding standards:
• MPEG-2 support
• MPEG-1: Full feature support
• H.263 support
• MPEG-4: Only supports some features in the simple profile
The HWMC interface supports Hardware Video Acceleration Compatible API’s (HVA).
6.4.8.2
6.4.8.3
Hardware Motion Compensation
The HWMC process consists of reconstructing a new picture by predicting (either forward,
backward, or bi-directional) the resulting pixel colors from one or more reference pictures. The
GMCH receives the video stream and implements Motion Compensation and subsequent steps in
hardware. Performing Motion Compensation in hardware reduces the processor demand of
software-based MPEG-2 decoding, and thus improves system performance.
Sub-picture Support
Sub-picture is used for two purposes: Subtitles for movie captions, which are superimposed on a
main picture, and for menus to provide some visual operation environments for the user.
DVD allows movie subtitles to be recorded as sub-pictures. On a DVD disc, it is called subtitle
because it has been prepared for storing captions. Since the disc can have a maximum of 32 tracks
for subtitles, they can be used for various applications, for example, as Subtitles in different
languages.
There are two kinds of menus, the System menus and other In-Title menus. First, the System
menus are displayed and operated at startup of or during the playback of the disc or from the stop
state. Second, In-Title menus can be programmed as a combination of Sub-picture and Highlight
commands to be displayed during playback of the disc.
The GMCH supports sub-picture for DVD by mixing the two video streams via alpha blending.
Unlike color keying, alpha blending provides a softer effect and each pixel that is displayed is a
composite between the two video stream pixels. The GMCH can utilize four methods when dealing
with sub-pictures. This flexibility means that the GMCH can work with all sub-picture formats.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
6.5
Internal Graphic Display Interface
The GMCH has three dedicated display ports: an Analog CRT port and two Digital display ports,
DVOB and DVOC.
When the GMCH is strapped to operate in Native Graphic Mode, the DVOB and DVOC can
support down stream devices such as TV-out encoders, external DACs, LVDS transmitters, and
TMDS transmitters. Each display port has control signals that may be used to control, configure
and/or determine the capabilities of an external device. The data that is sent out the display ports
are selected from one of the two possible sources, display pipe A or display pipe B.
The GMCH's digital display port is capable of driving a 165-MHz pixel clock on a single DVO
port, or a 330-MHz pixel clock by combining DVOB and DVOC.
6.5.1
Pipe A Timing Generator Unit
The Pipe A Timing generator provides the basic timing information for Display Pipe A. Timings
are composed of blank, sync, border and active periods. The active period represents the data area;
this is normally the size of a fixed resolution display or the selected resolution. Sync happens only
within blank periods thereby dividing the blank into three regions consisting of a front porch, sync
time, and back porch. Borders only happen directly before the start of blank and directly after the
end of blank. Borders are referred to as left, right, top, or bottom. The Pipe A timing generator has
been adapted to offer interlace support for the generation of HSYNC and VSYNC relative timing
to support downstream field identification. It has also been adapted to provide interlace timing
support for 480i and PAL formats. The following sections detail the features supported by the
®
Intel 82854 GMCH.
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Functional Description
6.5.1.1
ARIB Support
Please refer to the ARIB TR-B15 Operational Guidelines for Digital Satellite Broadcasting
(detailed Implementation guideline for receiver) for an exhaustive coverage of this topic
®
Figure 8.
ARIB TR-B15 Plane Resolutions
Plane name
Requirements
Resolution
1920x1080x16,YCbCr(4:2:2), 16:9
Still Picture Plane
720x480x16,YCbCr(4:2:2), 16:9
720x480x16,YCbCr(4:2:2), 4:3
960x540x8, 16:9 (Display resolution is 1920x1080 – 1 pixel on the plane is transferred to 2x2 pixel on display)
Text and Graphic
Plane
Resolution
CLUT
720x480x8, 16:9
720x480x8, 4:3
Number of CLUTs: 1
Standard fixed color: 128 colors
Receiver dependent color: 32 colors
Vender dependent color: 96 colors
8 bit index of CLUT input is tranfered to YCbCr (4:2:2) and 4 bit alpha value
Translation
Resolution
960x540x8, 16:9 (Display resolution is 1920x1080 – 1 pixel on the plane is transferred to 2x2 pixel on display)
Superimpose text
plane
720x480x8, 16:9
720x480x8, 4:3
Number of CLUTs: 1
CLUT
Standard fixed color: 128 colors
Receiver dependent color: 32 colors
Vender dependent color: 96 colors
8 bit index of CLUT input is tranfered to YCbCr (4:2:2) and 4 bit alpha value
Translation
6.5.1.2
H, V timing signals for active and blank timing
®
is support for NTSC and High Definition.
®
The progressive timing modes are supported by the Intel 82854 GMCH in Native Graphic Mode.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
Figure 9.
H, V Parameters
Parameter
480i
480p
720p
750
1080i
1080p
1125
576i
768p
Total
Vert ical
Lines
525
480
525
480
525
525
1125
1080
625
576
802
805
Active
Vert ical
Lines
480
45
480
45
720
30
1080
45
768
34
768
37
Total Blank
Lines
45
45
45
49
0-239
0-239
0-539
0-287
Active Line
Number
263-502
263-502
0-479
858
0-479
858
0-719
1650
563-1102
0-1079
2200
313-600
0-767
1688
0-767
1656
Total Pixels
per Line
858
720
858
640
2200
1920
864
720
Active Pixels
per Line
720
640
1280
1920
1280
1366
Blank Pixels
per Line
138
218
138
27
218
27
370
280
280
144
408
290
Pixel Clock
[MHz]
13.5
13.5
74.25
74.25
148.5
13.5
81.23
79.99
6.5.1.3
HSYNC/VSYNC Field Timing
The interlace timing is provided on the timing generator associated with Display Pipe A. When
data is being driven out of the device, HSYNC and VSYNC accompanies or frames the data.
Interlace timing requires that frame data is sent as two fields. Field1 data is scanned out first
followed by Field2. The Pipe A timing produces a field timing signal (Field1) that is used by the
Video Overlay and Display Plane A to produce Field1/Field2 data.
Downstream devices use the relative placement of the VSYNC and HSYNC timing signals to
discern field timing. For Field1 detection, the rising (asserting) edge of VSYNC is coincident with
the rising (asserting) edge of HSYNC. For Field2 detection, VSYNC is asserted after the HSYNC
Figure 10.
Interlaced Timing Using HSYNC and VSYNC for Field1/Field2 Downstream
Detection
VSYNC
HSYNC
Field2
Field1
D > 1/2 line
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Functional Description
Following conditions should be met for the sync (HSYNC, VSYNC) and blank (HBLANK,
VBLANK) signals:
• Start of H(V)SYNC can not coincide with start of H(V)BLANK
• H(V)SYNC should always start after H(V)BLANK starts.
In interlaced mode, the Vertical Total (VTOTAL_A register bits 27:16), Vertical Blank End
(VBLANK_A register bits 27:16), Vertical Sync Start (VSYNC_A register bits 11:0) and Vertical
Sync End (VSYNC_A register bits 27:16) must be programmed to a value 1 less than that of
program the register (VBLANK_A register bits 27:16) as 523 (note that it is 524 for progressive
case). This is needed as the line counter is stalled for one line when the Vsync assertion is shifted
between field1 and field2.
6.5.2
6.5.3
Blend Function
The blending unit is responsible for combining display planes onto a display pipe. This is done
using an alpha blending technique that is described as "pre-multiplied source over destination" or a
simple mux operation.
Interlaced Video Field display
®
The Intel 82854 GMCH provides interlace timing support for only Plane A and the Video
Overlay window. Interlace timing is not available for Plane B, Plane C, Hardware Cursor A,
Hardware Cursor B and the VGA plane. The Pipe A timing generator provides the interlace timing
for Plane A and the Video Overlay.
6.5.3.1
Interlace support for Plane A graphics
®
In the Intel 82854 GMCH, all the graphic features in Native Graphic mode are supported in Plane
A, under progressive mode.
In interlace mode, support for Field1 and Field2 timing generation is supported by Plane A. Plane
A makes use of the DPODPfieldID signal generated by the Pipe A timing generator to synchronize
the field timing. This signal is used to indicate which field of the picture should be scanned out.
When DPODPfieldID is high, Field1 is scanned out. The DPODPfieldID is used to set the vertical
line counters to the first line. The counters then increment by two until the end of the field is
reached. During the VBI interval, the DPODPfieldID transitions to low indicating that Field2 is
being processed next. This sets the vertical line counters to the second line and Field2 is then
scanned out.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
6.5.3.2
ARIB 960 X 540 support
In order to support the conversion of a 960x540 or a 960x1080 Plane A buffer to 1920x1080i, the
GMCH supports pixel doubling in the horizontal direction and field replication in the vertical
direction. In order to activate this functionality, interlace mode bit 20 in the DVOC- Digital
Display Port C Register must be programmed to a 1. Register DSPACNTR-Display A Plane
Control Register bits 21:20 are used to program the pixel doubling functionality. The following
depicts the bit programming:
00 -
01 -
10 -
11 -
No pixel/line multiplication
Pixel AND Line doubling (not valid in interlaced mode)
Reserved
Pixel doubling ONLY (not validated in Native Graphic Mode)
The Field replication mode is used to create two fields of data from Plane A. This is accomplished
by scanning out Plane A once to produce Field1 and then rescanned out to produce Field2. In
normal interlaced mode, the DSPABASE Register is programmed to the frame buffer start address,
the DSPASTER Register is programmed with the frame buffer start address plus one line, and the
DSPASTRIDE Register is programmed to 2x the line increment of the image in the frame buffer.
For Field1, the DSPABASE and DSPASTRIDE Registers generate addresses into the frame buffer
for even lines of the image. For Field2, the DSPASTER and DSPASTRIDE Registers generate
addresses into the frame buffer to read odd lines of the image. In field replication mode, the
DSPABASE and DSPASTER Registers are programmed with the same start address of the image
in the frame buffer. The DSPASTRIDE register is programmed to the 1x line-to-line increment
value. With interlaced mode enabled, this will effectively scan out the identical frame buffer for
both Field1 and Field2.
Please note that programming bits 21:20 of the DSPACNTR Register to "01" while the interlaced
mode is enabled is illegal. In other words, Line doubling is undefined for the interlaced mode of
operation.
In order to archieve this, program the PLL to generate Dpclk/2 internally when the following bits
of the DSPACNTR-Display A Plane Control Register, bit 21:20, are programmed for pixel
duplication mode.
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Functional Description
6.5.4
Interlace support for Video Overlay Window
In interlace mode, support for Field1 and Field2 timing generation is supported by the Video
Overlay. The Video Overlay makes use of the DPODPfieldID signal generated by the Pipe A
timing generator to synchronize the field timing. This signal is used to indicate which field should
be scanned out. The Video Overlay determines the correct lines to be used to assemble Field1 and
Field2 during on the fly up and down scaling. The Bob method is used to generate the missing
field information for Field2 when an interlaced source is used.
Table 32.
DVO Control Data Bits
After rising edge of
1st pixel clock
2nd pixel clock
VSYNC
DVOB [23]
DVOB [22:12]
DVOB [10:0]
Buffer ID
Undefined
Undefined
Buffer ID
Horizontal image size
Vertical image size
The Display Pipe A timing registers:
HTOTAL_A
VBLANK_A
HBLANK_A
VSYNC_A
HSYNC_A
PIPEASRC
VTOTAL_A
will hold data associated with physical buffer 0.
The Display Pipe B timing registers:
HTOTAL_B
VBLANK_B
HBLANK_B
VSYNC_B
HSYNC_B
PIPEBSRC
VTOTAL_B
will hold data associated with physical buffer 1.
The start address of physical buffer 0 will be in DSPABASE and the start address of physical buffer
1 will be in DSPASEC. The stride for both buffers will be in DSPASTRIDE. Refer to Section 4.0,
“Register Description” on page 41 for programming details.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
Figure 11 shows how the timing registers switch while the buffer 0 and buffer 1 are scanned out.
Timing Register Switching
Figure 11.
VSYNC_A
VBLANK_A
VTOTAL_A
Buffer 0
MP@ML 720x480(i) / 720x480(p)
timing register switching
occurs on VBLANK rising edge
VSYNC_B
VBLANK_B
Buffer 1
VTOTAL_B
VBLANK
VTOTAL
04650438h
04650438h
062705A0h
062705A0h
VTOTAL_A
VTOTAL_B
As shown in the above figure, buffer switching in Multi-display mode occurs on VBLANK. Once
VBLANK is detected, horizontal and vertical counters are reset and register switching occurs.
These operations result in an extended HSYNC following the VBLANK. The HSYNC interval
following VBLANK rising edge in MTV mode can be calculated as follows:
When switching from Buffer0 to Buffer1:
HSYNC INTERVAL = HSYNC_B[27:16] + 8
When switching from Buffer1 to Buffer0:
HSYNC INTERVAL = HSYNC_A[27:16] + 8
Where HSYNC_A[27:16] and HSYNC_B[27:16] are the Horizontal Sync End values programmed
in the PipeA and PipeB Horizontal Sync Registers.
In addition, VBLANK is effectively started twice as a result of the counter reset. This results in
two lines of inactive data being repeated. VSYNC will start two lines later then the programmed
value, and the total number of lines is extended by two.
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Functional Description
6.5.5
Analog Display Port Characteristics
The Analog display port provides an RGB signal output along with an HSYNC and VSYNC
signal. There is an associated DDC signal pair that is implemented using GPIO pins dedicated to
the analog port. The intended target device is for a CRT based monitor with a VGA connector.
6.5.5.1
6.5.5.2
Integrated RAMDAC
The display function contains a 350-MHz, integrated, 24-bit, RAM-based Digital-to-Analog
Converter (RAMDAC) that transforms up to 2048X1536 digital pixels at a maximum refresh rate
of 75-Hz. Three, 8-bit DACs provide the R, G, and B signals to the monitor.
DDC (Display Data Channel)
DDC is defined by VESA. It allows communication between the host system and display. Both
configuration and control information can be exchanged allowing plug-and-play systems to be
realized. Support for DDC 1 and 2 is implemented.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
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Power and Thermal Management
7.0
Power and Thermal Management
®
The Intel 82854 GMCH is intended to be compliant with the following specifications and
technologies:
• APM Rev 1.2
• PCI Power Management Rev 1.0
• PC'99, Rev 1.0, PC'99A, and PC'01, Rev 1.0
• ACPI 1.0b and 2.0 support
• ACPI S0, S1-M, S3, S4, S5, C0, C1, C2, C3 states
• Internal Graphics Adapter D0, D1, D3 (Hot/Cold)
• On Die Thermal sensor, enabling core and system memory Write Thermal throttling for
prevention of catastrophic thermal conditions
• External Thermal sensor input pin
• Enabling DDR DIMM Thermal throttling
• The GMCH also reduces I/O power dynamically, by disabling sense amps on input buffers, as
well as tristating output buffers when possible
• Dynamic Clock Power Down reduces power in all modes of operation
• System memory Self-Refresh in C3 state
®
• The Intel 82854 GMCH reduces I/O power dynamically by disabling sense amps on the input
buffers, as well as tri-stating the output buffers when possible
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Intel 82854 Graphics Memory Controller Hub (GMCH)
7.1
General Description of Supported CPU States
C0 (Full On): This is the only state that runs software. All clocks are running, STPCLK is
deasserted, and the processor core is active. The processor can service snoops and maintain cache
coherency in this state.
C1 (Auto Halt): The first level of power reduction occurs when the processor executes an Auto-
Halt instruction. This stops the execution of the instruction stream and reduces the processor's
power consumption. The processor can service snoops and maintain cache coherency in this state.
C2 (Stop Grant): To enter this low power state, STPCLK is asserted. The processor can still
service snoops and maintain cache coherency in this state.
C3 (Sleep or Deep Sleep): In these states the processor clock is stopped. The GMCH assumes that
no Hub interface cycles (except special cycles) will occur while the GMCH is in this state. The
processor cannot snoop its caches to maintain coherency while in the C3 state. The GMCH will
transition from the C0 state to the C3 state when software reads the Level 3 Register. This is an
ACPI defined register but BIOS or APM (via BIOS) can use this facility when entering a low
power state. The Host Clock PLL within the GMCH can be programmed to be shut off for
increased power savings and the GMCH uses the DPSLP signal input for this purpose.
C4 (Deeper Sleep): The C4 state appears to the GMCH as identical to the C3 state, but in this state
the processor core voltage is lowered. There are no internal events in GMCH for the C4 state that
differ from the C3 state. (The C4 state is not supported by the Intel Celeron M Processor, or
Genuine Intel Processor).
7.2
General Description of ACPI States
Internal Graphics Adapter:
• D0 Full on, display active
• D1 Low power state, low latency recovery. No display, system memory retained
• D3 Hot - All state lost other than PCI config. system memory lost (optionally)
• D3 Cold - Power off
CPU:
• C0 Full On
• C1 Auto Halt
• C2 Stop Clock. Clk to CPU still running. Clock stopped to CPU core.
• C3 Deep Sleep. Clock to CPU stopped.
• C4 Deeper Sleep. Same as C3 with reduced voltage on the CPU.
System States:
• G0/S0 Full On
• G1/S1-MPower On Suspend (POS). System Context Preserved
• G1/S2Not supported.
• G1/S3Suspend to RAM (STR). Power and context lost to chipset.
• G1/S4Suspend to Disk (STD). All power lost (except wakeup on ICH4-M)
• G2/S5Soft off. Total reboot.
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Power and Thermal Management
7.3
Internal Thermal Sensor
This section describes the new on-die Thermal sensor capability.
7.3.1
Overview
The Thermal sensor functions are provided below:
Catastrophic Trip Point: This trip point is programmed through the BIOS during initialization.
This trip point is set at the temperature at which the GMCH should be shut down immediately with
minimal software support. The settings for this are lockable.
High Temperature Trip Point: This trip point is nominally 14ºC below the Catastrophic trip
point. The BIOS can be programmed to provide an interrupt when it is crossed in either direction.
Upon the trip event, Hardware Throttling may be enabled when the temperature is exceeded.
7.3.2
Hysteresis Operation
Hysteresis provides a small amount of positive feedback to the Thermal sensor circuit to prevent a
trip point from flipping back and forth rapidly when the temperature is right at the trip point.
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Intel 82854 Graphics Memory Controller Hub (GMCH)
7.4
External Thermal Sensor Input
An External Thermal sensor with a serial interface may be placed next to DDR SDRAM DIMM (or
any other appropriate platform location), or a remote Thermal Diode may be placed next to the
DDR DIMM (or any other appropriate platform location) and connected to the External Thermal
sensor. Intel advises that the External Thermal sensor contains some form of hysteresis, since none
is provided by the GMCH hardware.
The external sensor can be connected to the ICH4-M via the SMBus interface to allow
programming and setup by BIOS software over the serial interface. The External sensor's output
should include an Active-Low Open-Drain signal indicating an Over-Temp condition, which
remains asserted for as long as the Over-Temp Condition exists, and deasserts when temperature
has returned to within normal operating range. This External sensor output will be connected to the
GMCH input (EXTTS_0) and will trigger a Preset Interrupt and/or Read-Throttle on a level-
sensitive basis.
Additional External Thermal sensor's outputs, for multiple sensors, can be wire-OR'ed together
allow signaling from multiple sensors located physically separately. Software can, if necessary,
distinguish which DDR DIMM(s) is the source of the over-temp through the serial interface.
However, since the DDR DIMM(s) will be located on the same System Memory Bus Data lines,
any GMCH-based Read Throttle will apply equally.
Note: The use of external sensors that include an internal pull-up resistor on the open-drain Thermal trip
output is discouraged. However, it may be possible depending on the size of the pull-up and the
voltage of the sensor. Please refer to the Intel® 854 Chipset Platform Design Guide For Use with
Ultra Low Voltage Intel® Celeron® M Processor at 600 MHz (contact your Intel representative for
the latest version of this document).
7.4.1
Usage
External sensor(s) used for dynamic temperature feedback control:
• Sensor on DDR DIMMs, which can be used to dynamically control read throttling.
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Intel 82854 GMCH Strap Pins
®
8.0
Intel 82854 GMCH Strap Pins
8.1
Strapping Configuration
Table 33.
Strapping Signals and Configuration
Pin Name
Strap Description
Configuration
I/F Type Buffer Type
ADDID[0]
Native Graphic Mode
select
ADDID[0] = 0, Reserved
DVO
IN
ADDID[0] = 1, the Intel® 82854
GMCH is strapped to operate
under Native Graphic Mode
HSYNC
XOR Chain Test
ALL Z Test
Low = Normal Ops (Default)
High = XOR Test On
GPIO
GPIO
GPIO
DVO
OUT
OUT
OUT
BI
VSYNC
Low = Normal Ops (Default)
High = AllZ Test On
LCLKCTLB
DVODETECT
VTT Voltage Select
Low = Default
High = Reserved
*DVO Select (If
Low = DVO (Default)
High = Reserved
DVODETECT=0 during
Reset, ADDID[7:0] is
latched to the ADDID
Register)
GST[2]
* Clock Config: Bit_2
Please refer to Device #0
DVO
Out:
Function #3 (HPLLCC Register)
for proper GST[2:0] settings
0) Before CPURST#, there is an
internal pull-down
detail configurations on Intel
854 Straps for Frequency/CPU
1) Just out of CPURST#: These
pins are Hi-Z
2) C3: these pins are Hi-Z
3) S1-M: these pins are Hi-Z
4) Internal GFX D1/D3: these pins
are Hi-Z
5) S3: these pins are Power down
6) S4/S5: these pins are Power
down
GST[1]
GST[0]
*
* Clock Config: Bit_1
* Clock Config: Bit_0
Please refer to Device #0 Function #2 (ADD_ID – ADD Identification Register) for proper Native Graphic
Mode settings.
External pull-ups/downs will be required on the board to enable the non-default state of the straps.
®
Note: All strap signals are sampled with respect to the leading edge of the Intel 82854 GMCH PWROK
In signal.
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
®
Table 34.
Intel 82854 GMCH Straps for Frequency/CPU Configuration
GST[2:0]
LCLKCTLB
CPU
FSB Freq
DDR Freq
Gfx Freq
Core Vcc
000
0
Intel Celeron M Processor
Family, Genuine Intel
Processor
400MHz
266MHz
200MHz
1.5V
111
0
Intel Celeron M Processor
Family, Genuine Intel
Processor
400MHz
333MHz
250MHz
1.5V
152
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Ballout and Package Information
9.0
Ballout and Package Information
®
Figure 12.
Intel 82854 GMCH Ballout Diagram (Top View)
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
SMVREF
_0
SMVSWI
NGL
SMVSWI
NGH
VCCQS
M
VCCQS
M
AJ
AH
AG
AF
AE
AD
AC
AB
AA
Y
NC
NC
NC
VSS
VSS
VCCSM
VSS
VCCSM
VSS
VSS
VCCSM
VCCSM
VSS
VSS
VSS
VCCSM
VSS
VCCSM
NC
VSS
NC
VSS
NC
AJ
AH
AG
AF
AE
AD
AC
AB
AA
Y
SDM[7] SDQS[7] SDQ[56] SDQ[51] SDQS[6] SDQ[49] SDQ[43] SDQ[46] SDQ[40] SDQ[45] SDQ[38] SDQS[4] SDQ[32] SDM[8]
RSVD SDQ[31] SDM[3] SDQ[25] SDQ[24] SDQ[18] SDQS[2] SDQ[20] SDQ[15] SDQS[1] SDQ[13] SDQ[7] SDQ[3]
VCCSM SDQ[58]
VSS
SDQ[60] SDQ[55]
VSS
SDQ[52] SDQ[47]
VSS
SDQ[41] SDQ[39]
VSS
SDQ[33] RSVD
VSS
RSVD SDQ[26]
VSS
SDQ[28] SDQ[19]
VSS
SDQ[17] SDQ[10]
VSS
SDQ[9] SDQ[6]
VSS
SDQS[0] VCCSM
VCCAS
VCCSM SDQ[59] VCCSM SDQ[61] SDQ[54] VCCSM SDQ[53] SDQ[42] VCCSM SDQ[44] SDQ[34] VCCSM RSVD
RSVD VCCSM SDQ[27] SDQ[30] VCCSM SMAB[4] SDQ[22] VCCSM SDQ[16] SDQ[14] VCCSM SDQ[12] SDQ[2] VCCSM SDQ[0]
M
BCLK
VSS
SDQ[62] SDQ[57]
VSS
SDQ[50] SDQ[48]
VSS
SDQS[5] SDQ[35]
VSS
SDQ[37] RSVD
VSS
RSVD
RSVD
VSS
SDQS[3] SDQ[23]
VSS
SDM[2] SDQ[11]
VSS
SDM[1] SDM[0]
VSS
SDQ[1] SDQ[5]
VSS
VCCAS
M
BCLK# RSTIN# SDQ[63] SCS[1]# SWE# SDM[6] SCS[0]# SBA[0] SDM[5] SBA[1] SDM[4] SDQ[36] SMA[3] SMAB[1] SDQS[8] SMA[1] SMA[2] SDQ[29] SMA[4] SMAB[5] SDQ[21] SMA[6] SMA[7] SDQ[8] SMA[11] SCK[2]# SDQ[4] SCK[3]#
RCVENI RCVEN
VCCSM
VSS
VSS
SCK[1] SCS[3]# SCAS#
VSS
SCS[2]# SRAS#
VSS
VCCSM
VSS
SMA[10] SMA[0]
VSS
VSS
VCC
VSS
VCCSM
VSS
SMA[5] SMAB[2]
VSS
VSS
SCKE[3] SCKE[2]
VSS
SCKE[0] SMA[8] SMA[9]
VSS
SCK[2] SCK[3] VCCSM
SMRCO
VCCSM SCKE[1] VCCSM SMA[12] SCK[5]# VCCSM SCK[0]
N#
OUT
VTTLF HA[31]# HA[29]#
VSS
SCK[1]# SCK[4]# SCK[4] VCCSM
VSS
VSS
VSS
VCC
VCCSM
VSS
VCCSM
VSS
VSS
VCCSM
VSS
VCCSM
VSS
VSS
NC
MP
HADSTB
[1]#
VSS
VTTLF
VSS
HA[27]# HA[22]#
HCCVRE
VSS
VSS
VSS
RSVD
VSS
VCC
VCCSM
VCCSM
VCCSM
VSS
VSS
VCCSM
HL[7]
VCCSM RSVD
VSS
SCK[5] SCK[0]#
VCCAGP
VSS
HA[26]# HA[30]# HA[21]# HA[17]# DPSLP# HAVREF
VSS
VCCSM
VSS
VSS
HL[5]
VSS
VCCHL
HL[9]
VCCSM GCLKIN
VCCHL
F
LL
W
V
HA[28]# HA[25]#
VSS
HA[20]# HA[23]# HA[24]#
VSS
VCC
VCCHL
VSS
VSS
HL[10]
HL[1]
VSS
HLSTB
HL[4] HLVREF
W
V
VTTHF HA[11]# HA[14]# HA[16]# HA[18]#
VSS
HA[19]# VTTLF
VSS
VCCHL
VSS
VCCHL
HL[0]
HL[6]
HL[3] HLSTB# VCCHL
U
VSS
HA[10]# HA[12]#
HA[5]# HA[13]#
VSS
HA[15]# HA[8]#
HA[7]#
VSS
VTTLF
VSS
VTTLF
VSS
VSS
VCC
VSS
VCC
VSS
VCC
VSS
VCC
VSS
VCC
VSS
VCC
VSS
VCC
VSS
VCC
VSS
VCC
VSS
VCC
VSS
VCC
VSS
VCC
VSS
VCCHL
VSS
VCCHL
RSVD
RSVD
RSVD
VSS
HL[2] PSWING
VSS
U
HADSTB
[0]#
HREQ[4]
#
MDDCD
ATA
HLRCO
T
HA[4]#
VSS
HA[9]#
VSS
VSS
RSVD
RSVD
RSVD
RSVD
RSVD
HL[8]
MP
T
HREQ[0]
HA[6]#
#
HREQ[3]
#
HREQ[2]
#
VCCDV
O
R
VSS
VTTLF
VSS
VSS
VSS
RSVD
RSVD
VSS
RSVD
RSVD
RSVD
VSS
R
HREQ[1]
#
VCCDV
O
MDDCC
LK
P
BPRI# HLOCK# RS[1]#
HA[3]#
VTTLF
VSS
VSS
RSVD
RSVD
RSVD
RSVD
P
VCCDV MDVICL MI2CDA
VCCDV
O
N
VSS
HITM#
HIT#
VSS
BNR#
DRDY# RS[0]#
VTTLF
VSS
VSS
N
O
K
TA
VCCDV VCCDV
MDVIDA
TA
VCCDV DVOBC
M
L
VTTHF DEFER# RS[2]# DBSY# HTRDY#
VSS
BREQ0# VTTLF
VSS
RSVD
VSS
M
L
O
O
O
CLKINT
VCCDV DVODET
DVOCVS
YNC
DVOCBL
ANK#
VSS
VTTLF
VSS
ADS#
HD[6]#
VSS
HD[8]# HD[3]# HD[7]#
VSS
VTTLF
VSS
VSS
RSVD
O
ECT
HYSWIN HDSTBP
HDVREF
[0]
VCCDV
O
MI2CCL DVOCH DVOCD[
DVOCD[ DVOCD[ DVOCD[
2] 3] 1]
K
HD[13]# HD[2]#
VSS
HD[11]# HD[0]#
VSS
VSS
K
G
[0]#
K
SYNC
0]
HDSTBN
[0]#
HDVREF
[1]
HDVREF
[2]
VCCDV
O
DVOCD[ DVOCD[ VCCDV DVOCCL DVOCCL VCCDV
4] 5] K#
J
HD[4]#
VSS
DINV[0]# HD[9]# HD[14]#
VSS
VSS
VTTLF
VSS
VSS
VSS
VCC
VSS
VSS
VCC
VCC1_5
VSS
VSS
PWROK
VSS
VSS
HSYNC
RSVD
VSYNC
VSS
J
O
K
O
HYRCO
MP
LCLKCT
LA
VCCDV DVOCD[ DVOCFL DVOCD[ DVOCD[ DVOCD[ DVOCD[
H
VTTHF
VSS
HD[1]# HD[15]# HD[10]#
VSS
HD[19]# VTTLF
VSS
VTTLF
VTTLF
VSS
VTTLF
RSVD
VSS
H
O
10]
DSTL
9]
8]
6]
7]
DDCADA
TA
DVOCD[ DVOBCI
11] NTR#
G
HD[5]# HD[12]#
VSS
HD[21]# HD[24]# HD[30]# HD[27]# HD[33]# HD[40]# DINV[3]# HD[48]# HD[51]# HD[58]# VTTLF
CPURST
RSVD VCC1_5 RSVD
RSVD
VSS
RSVD
VSS ADDID[6] ADDID[4] VSS
VSS
G
F
VTTLF HD[22]#
VSS
HD[17]# HD[16]#
VSS
HD[44]#
VSS
HD[45]#
VSS
HD[53]#
VSS
HD[56]#
VSS
RSVD
RSVD
RSVD
RSVD
VSS
RSVD
VSS
RSVD
RSVD
RSVD
RSVD
RSVD
RSVD VCC2_5 RSVD
RSVD ADDID[7] ADDID[1] ADDID[5] RSVD
RSVD GVREF
VCCDV
F
#
HDSTBN HDSTBP
HDSTBP
[3]#
VCCDV
O
VCCDV
O
E
VSS
VSS
VSS
HD[20]# HD[29]# DINV[1]# HD[38]# HD[41]#
HDSTBP
HD[50]# HD[49]#
HD[61]# HD[59]# RSVD
RSVD
VSS
RSVD
VSS
REFSET
VSS
ADDID[0]
DPMS
RSVD
VSS
ADDID[2] ADDID[3]
E
[2]#
[2]#
O
VCCAHP
LL
HDSTBN
[3]#
EXTTS_
0
DVORC
OMP
D
HD[23]#
VSS
HD[39]#
VSS
HD[36]#
VSS
HD[52]#
VSS
VSS
HD[62]#
VSS
VCC2_5 BLUE# GREEN# RSVD
VSS
RSVD
RSVD
D
[1]#
HDSTBN
[1]#
LCLKCT
LB
C
VSS
NC
NC
29
HD[25]#
HD[28]# HD[37]# HD[34]# HD[35]#
VSS
HD[47]# HD[46]# HD[54]# HD[63]# HD[55]# HD[60]# RSVD
RSVD
RSVD
VSS
BLUE GREEN
VSS
GST[0] GST[1] GST[2]
VSS
NC
C
HXRCO
MP
HXSWIN
G
VCCADP
LLB
VCCADA VSSADA DREFCL DDCACL
B
HD[31]# HD[18]# HD[26]# DINV[2]#
VSS
VTTHF
24
HD[43]# HD[42]# HD[32]#
HD[57]#
VSS
RSVD
VSS
17
VCC1_5 VCC1_5 RSVD
VSS
VSSA VCC2_5
RSVD
RSVD
RSVD
NC
B
C
C
K
K
VCCADA
C
VCCADP
LLA
VCCGPI VCCGPI
A
NC
28
VSS
27
VTTLF
26
VSS
25
VSS
23
VTTHF
22
VSS
21
VTTLF
20
VTTLF
18
VCC2_5 VCCA
RSVD
10
RED#
RED
RSVD
5
A
O
O
19
16
15
14
13
12
11
9
8
7
6
4
3
2
1
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
9.1
VCC/VSS Voltage Groups
Table 35.
Voltage Levels and Ball Out for Voltage Groups
Name
Voltage Level
Ball out
VCC
1.5
H14,J15,N14,N16,P13,P15,P17,R14,R16,T13,T15,
T17,U14,U16,W21,AA15,AA17,AA19
VCCADAC
VCCDVO
VCCASM
VCC1_5
VCCGPIO
VCCHL
1.5
1.5
1.5
1.5
3.3
1.5
2.5
2.5
A9,B9
E1,E4,E6,H7,J1,J4,J8,K9,L8,M4,M8,M9,N1,N8,P9,R8
AD1,AF1
B14,B15,G13,J13
A3,A4
U6,U8,V1,V7,V9,W5,W8,Y1
AJ6,AJ8
VCCQSM
VCCSM
Y4,Y7,Y9,AA6,AA8,AA11,AA13,AB3,AB6,AB8,AB10,
AB12,AB14,AB16,AB18,AB20,AB22,AC1,AC29,AF3,
AF6,AF9,AF12,AF15,AF18,AF21,AF24,AF27,AF29,
AG1,AG29,AJ5,AJ9,AJ13,AJ17,AJ21,AJ25
VCC2_5
VTTHF
VTTLF
2.5
1.5
1.5
A12,B10,D10,F9
A22,A24,H29,M29,V29
A18,A20,A26,F29,G15,H16,H18,H20,H22,J19,K29,L21,
M22,N21,P22,R21,T22,U21,V22,Y29,AB29
VSS
GND
A13,A17,A19,A21,A23,A25,A27,B5,B24,C1,C7,C10,C22,C29,
D4,D11,D13,D15,D17,D19,D21,D23,D25,D28,E7,E9,E28,E29,
F11,F13,F16,F18,F20,F22,F24,F27,G1,G4,G7,G26,G29,H8,H11,
H13,H15,H17,H19,H21,H24,J7,J10,J12,J14,J16,J18,J20,J22,J26,
J29,K4,K8,K24,L1,L6,L9,L22,L26,L29,M7,M21,M24,N4,N9,N13,
N15,N17,N22,N26,N29,P8,P14,P16,P21,P24,R2,R7,R9,R13,R15,
R17,R22,R26,T4,T8,T9,T14,T16,T21,T24,U1,U5,U9,U13,U15,
U17,U22,U26,U29,V8,V21,V24,W4,W9,W22,W26,W29,Y5,Y6,
Y8,Y21,AA1,AA4,AA7,AA10,AA12,AA14,AA16,AA18,AA20,
AA21,AA23,AA24,AA25,AA29,AB9,AB11,AB13,AB15,AB17,
AB19,AB21,AB26,AC4,AC8,AC11,AC14,AC17,AC20,AC23,
AC27,AC28,AE1,AE4,AE7,AE10,AE13,AE16,AE19,AE22,AE25,
AE28,AG3,AG6,AG9,AG12,AG15,AG18,AG21,AG24,AG27,AJ1,
AJ3,AJ7,AJ10,AJ11,AJ12,AJ18,AJ20,AJ23,AJ26,AJ27
154
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Ballout and Package Information
Table 36.
Ballout Table
Row
Column
Signal Name
Row
Column
Signal Name
Row
Column
Signal Name
E
5
ADDID[0]
ADDID[1]
ADDID[2]
ADDID[3]
ADDID[4]
ADDID[5]
ADDID[6]
ADDID[7]
ADS#
AA
N
B
B
L
22
24
7
DPWR#
G
K
K
J
3
DVOCD[11]
DVOCD[2]
DVOCD[3]
DVOCD[4]
DVOCD[5]
DVOCD[6]
DVOCD[7]
DVOCD[8]
DVOCD[9]
DVOCFLDSTL
DVOCHSYNC
DVOCVSYNC
DVODETECT
DVORCOMP
EXTTS_0
GCLKIN
F
5
DRDY#
3
E
3
DREFCLK
RSVD
2
E
2
17
2
6
G
F
5
DVOBBLANK#
DVOBCCLKINT
DVOBCINTR#
DVOBCLK
DVOBCLK#
DVOBD[0]
DVOBD[1]
DVOBD[10]
DVOBD[11]
DVOBD[2]
DVOBD[3]
DVOBD[4]
DVOBD[5]
DVOBD[6]
DVOBD[7]
DVOBD[8]
DVOBD[9]
DVOBFLDSTL
DVOBHSYNC
DVOBVSYNC
DVOCBLANK#
DVOCCLK
DVOCCLK#
DVOCD[0]
DVOCD[1]
DVOCD[10]
J
5
4
M
G
P
P
R
R
M
M
R
R
P
P
N
P
N
N
M
T
3
H
H
H
H
H
K
L
2
G
F
6
2
1
6
3
3
L
28
7
4
4
F
RSVD
3
5
AE
AD
C
D
N
P
29
29
9
BCLK
5
6
BCLK#
1
5
BLUE
5
L
7
9
BLUE#
6
D
D
Y
C
D
F
1
25
28
23
15
26
6
BNR#
4
6
BPRI#
6
3
M
F
BREQ0#
CPURST#
DBSY#
5
8
GREEN
5
8
GREEN#
GVREF
M
B
2
1
DDCACLK
DDCADATA
RSVD
2
U
V
U
T
28
28
27
27
27
25
26
24
25
23
25
HA[10]#
G
B
9
3
HA[11]#
4
2
HA[12]#
C
M
J
5
RSVD
6
HA[13]#
28
25
25
25
19
5
DEFER#
DINV[0]#
DINV[1]#
DINV[2]#
DINV[3]#
DPMS
T
5
V
U
V
Y
V
V
W
HA[14]#
L
3
HA[15]#
E
J
3
HA[16]#
B
J
2
HA[17]#
G
D
Y
K
K
H
5
HA[18]#
1
HA[19]#
23
DPSLP#
6
HA[20]#
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
Row
Column
Signal Name
Row
Column
Signal Name
Row
Column
Signal Name
Y
25
27
24
23
27
27
28
28
27
23
26
28
25
28
27
23
24
24
26
26
22
28
22
27
25
23
27
26
23
26
HA[21]#
HA[22]#
HA[23]#
HA[24]#
HA[25]#
HA[26]#
HA[27]#
HA[28]#
HA[29]#
HA[3]#
F
25
26
27
23
25
27
25
28
27
24
28
26
22
26
26
24
23
28
21
21
24
23
22
25
24
24
27
20
23
22
HD[16]#
HD[17]#
HD[18]#
HD[19]#
HD[2]#
B
F
F
C
C
G
E
G
E
G
D
F
C
C
F
B
G
E
L
23
23
21
20
21
18
19
28
20
17
20
19
19
17
17
19
16
16
27
16
17
16
18
23
25
24
28
27
22
18
HD[43]#
HD[44]#
HD[45]#
HD[46]#
HD[47]#
HD[48]#
HD[49]#
HD[5]#
AA
W
W
W
Y
F
B
H
K
E
G
F
HD[20]#
HD[21]#
HD[22]#
HD[23]#
HD[24]#
HD[25]#
HD[26]#
HD[27]#
HD[28]#
HD[29]#
HD[3]#
AA
W
AB
P
D
G
C
B
G
C
E
L
HD[50]#
HD[51]#
HD[52]#
HD[53]#
HD[54]#
HD[55]#
HD[56]#
HD[57]#
HD[58]#
HD[59]#
HD[6]#
Y
HA[30]#
HA[31]#
HA[4]#
AB
T
T
HA[5]#
R
HA[6]#
U
HA[7]#
U
HA[8]#
G
B
B
G
C
C
D
C
E
D
J
HD[30]#
HD[31]#
HD[32]#
HD[33]#
HD[34]#
HD[35]#
HD[36]#
HD[37]#
HD[38]#
HD[39]#
HD[4]#
R
HA[9]#
T
HADSTB[0]#
HADSTB[1]#
HAVREF
HCCVREF
HD[0]#
AA
Y
C
E
D
C
L
HD[60]#
HD[61]#
HD[62]#
HD[63]#
HD[7]#
Y
K
H
HD[1]#
H
HD[10]#
HD[11]#
HD[12]#
HD[13]#
HD[14]#
HD[15]#
L
HD[8]#
K
J
HD[9]#
G
K
J
HDSTBN[0]#
HDSTBN[1]#
HDSTBN[2]#
HDSTBN[3]#
G
E
B
HD[40]#
HD[41]#
HD[42]#
C
E
D
J
H
156
D15343-003
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Ballout and Package Information
Row
Column
Signal Name
Row
Column
Signal Name
Row
Column
Signal Name
K
D
E
E
K
J
27
26
21
18
21
21
17
27
28
7
HDSTBP[0]#
HDSTBP[1]#
HDSTBP[2]#
HDSTBP[3]#
HDVREF[0]
HDVREF[1]
HDVREF[2]
HIT#
H
M
B
B
H
K
D
E
E
F
10
25
20
18
28
28
14
13
10
10
14
15
15
13
14
14
14
13
12
12
12
11
12
11
11
10
9
HSYNC
HTRDY#
HXRCOMP
HXSWING
HYRCOMP
HYSWING
RSVD
T
7
MDDCDATA
MDVICLK
MDVIDATA
MI2CCLK
MI2CDATA
NC
N
7
M
K
6
7
N
6
AJ
AH
B
29
29
29
29
28
28
9
J
NC
N
N
U
U
V
U
V
W
W
V
W
T
RSVD
NC
HITM#
RSVD
A
NC
HL[0]
RSVD
AJ
A
NC
4
HL[1]
G
E
C
C
F
RSVD
NC
4
HL[10]
RSVD
AA
AJ
AJ
A
NC
3
HL[2]
RSVD
4
NC
3
HL[3]
RSVD
2
NC
2
HL[4]
RSVD
2
NC
6
HL[5]
E
C
B
H
E
C
G
G
E
C
G
H
C
A
P
RSVD
AH
B
1
NC
6
HL[6]
RSVD
1
NC
7
HL[7]
RSVD
G
8
RSVD
RSVD
RSVD
PSWING
PWROK
RCVENIN#
RCVENOUT#
RED
3
HL[8]
RSVD
F
8
V
P
T
5
HL[9]
RSVD
A
5
27
2
HLOCK#
HLRCOMP
HLSTB
RSVD
U
2
RSVD
J
11
16
15
7
W
V
W
R
P
R
R
T
3
RSVD
AC
AC
A
2
HLSTB#
HLVREF
HREQ[0]#
HREQ[1]#
HREQ[2]#
HREQ[3]#
HREQ[4]#
RSVD
1
RSVD
28
25
23
25
23
RSVD
A
8
RED#
REFSET
RS[0]#
RS[1]#
RS[2]#
LCLKCTLA
LCLKCTLB
RSVD
E
8
6
N
23
26
27
10
7
P
MDDCCLK
M
D15343-003
157
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
Row
Column
Signal Name
Row
Column
Signal Name
Row
Column
Signal Name
AD
F
28
12
12
12
5
RSTIN#
RSVD
AB
AC
AB
AC
AC
AD
AD
AC
AC
AE
AE
AE
AH
AD
AD
AD
AH
AH
AF
AE
AG
AE
AF
AH
AF
AH
AF
AG
AH
AG
4
SCK[5]#
SCKE[0]
SCKE[1]
SCKE[2]
SCKE[3]
SCS[0]#
SCS[1]#
SCS[2]#
SCS[3]#
SDM[0]
SDM[1]
SDM[2]
SDM[3]
SDM[4]
SDM[5]
SDM[6]
SDM[7]
SDM[8]
SDQ[0]
AF
AH
AD
AF
AE
AH
AH
AG
AF
AG
AD
AH
AF
AH
AH
AG
AF
AE
AD
AE
AH
AG
AD
AH
AG
AF
AH
AF
AH
AH
4
SDQ[2]
7
7
SDQ[20]
SDQ[21]
SDQ[22]
SDQ[23]
SDQ[24]
SDQ[25]
SDQ[26]
SDQ[27]
SDQ[28]
SDQ[29]
SDQ[3]
D
RSVD
7
9
B
RSVD
9
10
11
10
11
13
14
11
12
2
AA
L
RSVD
10
23
26
22
25
5
4
RSVD
C
4
GST[0]
RSVD
F
3
D
3
RSVD
C
3
GST[1]
RSVD
B
3
6
F
2
RSVD
9
D
2
RSVD
12
19
21
24
28
15
2
13
13
16
17
19
20
18
18
18
19
3
SDQ[30]
SDQ[31]
SDQ[32]
SDQ[33]
SDQ[34]
SDQ[35]
SDQ[36]
SDQ[37]
SDQ[38]
SDQ[39]
SDQ[4]
C
2
GST[2]
RSVD
B
2
D
7
RSVD
AD
AD
AC
AB
AA
AC
AB
AC
AD
AC
AD
AB
AB
AA
22
20
24
2
SBA[0]
SBA[1]
SCAS#
SCK[0]
SCK[0]#
SCK[1]
SCK[1]#
SCK[2]
SCK[2]#
SCK[3]
SCK[3]#
SCK[4]
SCK[4]#
SCK[5]
3
SDQ[1]
2
7
SDQ[10]
SDQ[11]
SDQ[12]
SDQ[13]
SDQ[14]
SDQ[15]
SDQ[16]
SDQ[17]
SDQ[18]
SDQ[19]
26
25
3
8
5
4
20
20
22
22
20
19
21
SDQ[40]
SDQ[41]
SDQ[42]
SDQ[43]
SDQ[44]
SDQ[45]
SDQ[46]
4
7
2
6
2
8
23
24
3
8
9
10
158
D15343-003
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Ballout and Package Information
Row
Column
Signal Name
Row
Column
Signal Name
Row
Column
Signal Name
AG
AE
AH
AE
AE
AH
AG
AF
AF
AG
AH
AE
AG
AF
AG
AG
AF
AE
AD
AG
AE
AE
AG
AH
AE
AH
AF
AF
AD
AG
22
23
23
2
SDQ[47]
SDQ[48]
SDQ[49]
SDQ[5]
SDQ[50]
SDQ[51]
SDQ[52]
SDQ[53]
SDQ[54]
SDQ[55]
SDQ[56]
SDQ[57]
SDQ[58]
SDQ[59]
SDQ[6]
SDQ[60]
SDQ[61]
SDQ[62]
SDQ[63]
RSVD
AG
AH
AH
AE
AH
AE
AH
AH
AD
AC
AD
AC
AD
AB
AD
AD
AD
AC
AD
AD
AC
AC
AD
AC
AF
AD
AB
AJ
2
SDQS[0]
SDQS[1]
SDQS[2]
SDQS[3]
SDQS[4]
SDQS[5]
SDQS[6]
SDQS[7]
SDQS[8]
SMA[0]
AC
AD
W
AA
AA
T
21
25
21
19
17
17
17
16
16
16
15
15
15
15
14
14
14
14
13
13
9
SRAS#
SWE#
VCC
5
8
12
17
21
24
27
15
18
14
19
5
VCC
24
25
23
23
25
25
26
26
28
28
4
VCC
VCC
P
VCC
U
VCC
R
VCC
N
VCC
SMA[1]
AA
T
VCC
SMA[10]
SMA[11]
SMA[12]
SMA[2]
VCC
P
VCC
5
J
VCC
13
17
11
13
8
U
VCC
26
26
27
27
14
14
17
16
14
15
3
SMA[3]
R
VCC
SMA[4]
N
VCC
SMA[5]
H
VCC
SMA[6]
T
VCC
7
SMA[7]
P
VCC
RSVD
6
SMA[8]
B
VCCADAC
VCCADAC
VCCADPLLA
VCCADPLLB
VCCAGPLL
VCCAHPLL
VCCA
VCCASM
VCCASM
VCC1_5
RSVD
5
SMA[9]
A
9
RSVD
16
12
11
10
1
SMAB[1]
SMAB[2]
SMAB[4]
SMAB[5]
SMRCOMP
SMVREF_0
SMVSWINGH
SMVSWINGL
A
6
RSVD
B
16
2
RSVD
Y
SDQ[7]
RSVD
D
29
11
1
16
17
6
A
RSVD
24
19
22
AF
AD
B
SDQ[8]
SDQ[9]
AJ
1
5
AJ
15
D15343-003
159
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
Row
Column
Signal Name
Row
Column
Signal Name
Row
Column
Signal Name
B
J
14
13
13
9
VCC1_5
VCC1_5
VCC1_5
VCCDVO
VCCDVO
VCCDVO
VCCDVO
VCCDVO
VCCDVO
VCCDVO
VCCDVO
VCCDVO
VCCDVO
VCCDVO
VCCDVO
VCCDVO
VCCDVO
VCCDVO
VCCDVO
VCCGPIO
VCCGPIO
VCCHL
AJ
AG
AF
AC
AF
AJ
AF
AB
AJ
AF
AB
AF
AB
AJ
AB
AF
AB
AJ
AA
AF
AB
AA
AB
AJ
AF
Y
6
VCCQSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
AB
AA
AJ
Y
6
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCCSM
VCC2_5
VCC2_5
VCC2_5
VCC2_5
VSS
29
29
29
27
25
24
22
21
21
20
18
18
17
16
15
14
13
13
12
12
11
10
9
6
G
P
M
K
R
N
M
L
5
4
9
AF
AB
AG
AC
A
3
9
3
8
1
8
1
8
12
10
10
9
8
D
J
8
B
H
E
M
J
7
F
6
AA
W
U
29
29
29
29
29
29
29
29
29
28
28
28
28
27
27
27
27
27
4
VSS
4
VSS
E
N
J
4
N
VSS
1
L
VSS
1
J
VSS
E
A
A
V
W
U
V
U
W
Y
V
AJ
1
G
VSS
4
E
VSS
3
C
VSS
9
AE
AC
E
VSS
8
VCCHL
VSS
8
VCCHL
VSS
7
VCCHL
9
D
VSS
6
VCCHL
9
AJ
AG
AC
F
VSS
5
VCCHL
AB
AA
Y
8
VSS
1
VCCHL
8
VSS
1
VCCHL
7
VSS
8
VCCQSM
AF
6
A
VSS
160
D15343-003
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Ballout and Package Information
Row
Column
Signal Name
Row
Column
Signal Name
Row
Column
Signal Name
AJ
AB
W
U
26
26
26
26
26
26
26
26
26
25
25
25
25
24
24
24
24
24
24
24
24
24
24
23
23
23
23
23
22
22
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
U
22
22
22
22
22
22
22
21
21
21
21
21
21
21
21
21
21
21
20
20
20
20
20
19
19
19
19
19
18
18
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
AA
J
18
18
18
17
17
17
17
17
17
17
17
16
16
16
16
16
16
15
15
15
15
15
15
15
14
14
14
14
14
13
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
R
N
F
L
AC
AB
U
R
J
N
F
L
C
R
J
AG
AB
AA
Y
N
G
H
AE
AA
D
D
A
V
AE
AA
T
A
T
AG
AA
V
P
M
H
P
J
T
D
F
P
A
AG
AB
U
M
K
AJ
AC
AA
J
H
R
F
N
B
F
H
AJ
AC
AA
D
AE
AB
H
D
AC
AA
T
D
A
A
P
AE
W
AJ
AG
J
AE
D15343-003
161
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
Row
Column
Signal Name
Row
Column
Signal Name
Row
Column
Signal Name
AB
U
13
13
13
13
13
13
13
13
12
12
12
12
11
11
11
11
11
11
10
10
10
10
10
9
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
L
9
9
8
8
8
8
8
8
8
7
7
7
7
7
7
7
7
7
6
6
6
5
5
5
4
4
4
4
4
4
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
VSS
K
4
VSS
E
G
D
4
VSS
R
AC
Y
4
VSS
N
AJ
AG
R
3
VSS
H
V
3
VSS
F
T
2
VSS
D
P
AJ
AE
AA
U
1
VSS
A
K
1
VSS
AJ
AG
AA
J
H
1
VSS
AJ
AE
AA
R
1
VSS
L
1
VSS
G
C
1
VSS
AJ
AC
AB
H
1
VSS
M
J
B
8
VSSADAC
VSSA
VSYNC
VTTHF
VTTHF
VTTHF
VTTHF
VTTHF
VTTLF
VTTLF
VTTLF
VTTLF
VTTLF
VTTLF
VTTLF
VTTLF
VTTLF
B
11
9
G
J
F
E
V
29
29
29
24
22
29
29
29
29
26
22
22
22
22
D
C
M
H
AJ
AE
AA
J
AG
Y
A
L
A
Y
AB
Y
C
U
AG
AB
W
U
B
K
9
AE
AC
AA
W
T
F
9
A
9
V
T
9
T
R
9
P
N
9
N
M
162
D15343-003
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Ballout and Package Information
Row
Column
Signal Name
H
U
R
N
L
22
21
21
21
21
20
20
19
18
18
16
15
VTTLF
VTTLF
VTTLF
VTTLF
VTTLF
VTTLF
VTTLF
VTTLF
VTTLF
VTTLF
VTTLF
VTTLF
H
A
J
H
A
H
G
D15343-003
163
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®
Intel 82854 Graphics Memory Controller Hub (GMCH)
9.2
Package Mechanical Information
®
®
Intel 82854 GMCH. The Intel 82854 GMCH comes in a Micro-FCBGA package, which is
similar to the mobile processors. The package consists of a silicon die mounted face down on an
organic substrate populated with solder balls on the bottom side. Capacitors may be placed in the
area surrounding the die. Because the die-side capacitors are electrically conductive, and only
slightly shorter than the die height, care should be taken to avoid contacting the capacitors with
electrically conductive materials. Doing so may short the capacitors and possibly damage the
device or render it inactive.
The use of an insulating material between the capacitors and any thermal solution should be
considered to prevent capacitor shorting. An exclusion, or keepout area, surrounds the die and
capacitors, and identifies the contact area for the package. Care should be taken to avoid contact
with the package inside this area.
®
Figure 13.
Intel 82854 GMCH Micro-FCBGA Package Dimensions (Top View)
164
D15343-003
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|
