DLP-
USB245R
LEAD-FREE
USB-PARALLEL FIFO Module
The DLP-USB245R is DLP Design’s smallest USB-to-parallel FIFO interface module and
utilizes the popular FT245R IC with FTDIChip-ID™ feature from FTDI. In addition to enabling
standard USB-to-FIFO designs, both asynchronous and synchronous bit-bang interface modes
are also available.
The DLP-USB245R is available in a lead-free, RoHS-compliant, compact 18-pin, 0.1-inch
standard DIP footprint.
FEATURES:
• Single-chip USB-to-parallel FIFO bidirectional data-transfer interface.
• Entire USB protocol handled on the FT245R; no USB-specific firmware programming is
required.
• Fully integrated 1024-bit EEPROM storing device descriptors and FIFO I/O configuration.
• Data transfer rates up to 1Mbyte per second.
• 256-byte receive buffer and 128-byte transmit buffer utilizing buffer-smoothing technology to
allow for high data throughput.
• FTDI’s royalty-free Virtual COM Port (VCP) and direct (D2XX) drivers eliminate the requirement
for USB driver development in most cases.
• Unique USB FTDIChip-ID™ feature.
• Configurable FIFO interface I/O pins.
• Synchronous and asynchronous bit-bang interface options with RD# and WR# strobes.
• Device supplied preprogrammed with a unique USB serial number.
• Supports bus-powered, self-powered and high-power bus-powered USB configurations.
• Integrated level converter on FIFO interface for connection to external logic running at between
+1.8V and +5V.
• True 5V/3.3V/2.8V/1.8V CMOS drive output and TTL input.
• Configurable I/O pin output drive strength.
• Integrated power-on-reset circuit.
• Fully integrated power-supply filtering; no external filtering is required.
• +3.3V to +5.25V single-supply operation.
• Low operating and USB Suspend current.
• UHCI/OHCI/EHCI host-controller compatible.
• USB 2.0 full-speed compatible.
• -40°C to 85°C extended operating temperature range.
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ABSOLUTE MAXIMUM RATINGS
• Storage Temperature
• Ambient Temperature (Power Applied)
• VCC Supply Voltage
• DC Input Voltage: Inputs
• DC Input Voltage: High-Impedance Bidirectionals
• DC Output Current: Outputs
-65°C to +150°C
-40 to +85°C
-0.5V to +6.00V
-0.5V to VCC + 0.5V
-0.5V to VCC + 0.5V
24mA
D.C. CHARACTERISTICS (AMBIENT TEMPERATURE: -40 TO 85°C)
• VCC Operating-Supply Voltage
• VCCIO Operating-Supply Voltage
• Operating Supply Current
4.0 - 5.25V
4.0 - 5.25V
15mA (Normal Operation)
100uA USB Suspend
• Operating Supply Current
1.0 GENERAL DESCRIPTION
The DLP-USB245M provides an easy, cost-effective method of transferring data to/from a
peripheral and a host at up to 8 million bits (1 megabyte) per second. Its simple, FIFO-like
design makes it easy to interface to any microcontroller or microprocessor via I/O ports.
To send data from the peripheral to the host computer, simply write the byte-wide data into the
module when TXE# is low. If the (128-byte) transmit buffer fills up or is busy storing the
previously-written byte, the device takes TXE# high in order to stop further data from being
written until some of the FIFO data has been transferred over USB to the host.
When the host sends data to the peripheral over USB, the device will take RXF# low to let the
peripheral know that at least one byte of data is available. The peripheral then reads the data
until RXF# goes high, thereby indicating that no more data is available to be read.
By using FTDI’s Virtual COM Port drivers, the peripheral looks like a standard COM port to the
application software. Commands to set the baud rate are ignored; the device always transfers
data at its fastest rate regardless of the application’s baud-rate setting. The latest versions of
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2.0 TIMING DIAGRAMS
T6
T2
T5
RXF#
T1
RD#
T3
T4
D[7..0]
Valid data
Description Min Max Unit
TIME DESCRIPTION
MIN
50
50 + T6
MAX
UNIT
nS
nS
nS
nS
T1
T2
T3
T4
T5
T6
RD# Active Pulse Width
-
-
50
-
25
-
RD# to RD# Pre-Charge Time
RD# Active to Valid Data*
20
0
0
Valid Data Hold Time from RD# Inactive*
RD# Inactive to RXF#
nS
nS
RXF# Inactive After RD Cycle
80
*Load = 30pF
T12
T11
TXE#
T7
T8
WR
T10
T9
D[7..0]
Valid data
TIME DESCRIPTION
MIN
50
50
20
0
MAX
UNIT
nS
nS
nS
nS
T7
T8
WR Active Pulse Width
WR to WR Pre-Charge Time
-
-
-
-
25
-
T9
Valid Data Setup to WR Falling Edge*
Valid Data Hold Time from WR Inactive*
WR Inactive to TXE#
T10
T11
T12
5
80
nS
nS
TXE# Inactive After WR Cycle
*Load = 30pF
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3.0 APPLICATION NOTES
USB devices transfer data in packets. If data is to be sent from the PC, a packet is built up by
the application program and is sent via the device driver to the USB scheduler. This scheduler
adds a request to the list of tasks that the USB host controller will perform. This will typically
take at least 1 millisecond to execute because it will not pick up the new request until the next
USB frame (the frame period is 1 millisecond). There is, therefore, sizeable overhead
(depending upon your required throughput) associated with moving data from the application to
the USB device. If data is sent one byte at a time by an application, this will severely limit the
overall throughput of the system.
It must be stressed that in order to achieve maximum throughput, application programs should
send or receive data using buffers and not individual characters.
4.0 DRIVER SOFTWARE
FTDI's VCP (Virtual COM Port) driver-executable files are provided royalty free on the condition
that they are only used with designs incorporating an FTDI device (i.e. the FT245R and DLP-
USB245R). The latest version of the drivers can be downloaded from either
The CDM driver download file is a combined set of drivers for the Windows operating system
and contains both the VCP and D2XX driver versions. To download, simply unzip the file to a
folder on your PC. (The drivers can coexist on the same floppy disk or folder since the INF files
determine which set of drivers to load for each operating-system version.) Once loaded, the
VCP drivers will allow your application software—running on the host PC—to communicate with
the DLP-USB245R as though it were connected to a COM (RS-232) port.
In addition to VCP drivers, FTDI's D2XX direct drivers for Windows offer an alternative solution
to the VCP drivers that allow application software to interface with the FT245R device using a
DLL instead of a Virtual COM Port. The architecture of the D2XX drivers consists of a Windows
WDM driver that communicates with the FT245BR device via the Windows USB stack and a
DLL that interfaces with the application software (written in VC++, C++ Builder, Delphi, VB, etc.)
to the WDM driver.
The D2XX direct drivers add support for simultaneous access and control of multiple FT245R
devices. The extended open function (FT_OpenEx) allows the device to be opened either by its
product description or serial number, both of which can be programmed to be unique. The list
devices function (FT-ListDevices) allows the application software to determine which devices
are currently available for use, again by either product description or serial number.
Additional functions are provided to program the EEPROM (FT_EE_Program) and read the
EEPROM (FT_EE_Read). Unused space in the EEPROM is called the user area (EEUA), and
functions are provided to access the EEUA. FT_EE_UASize gets its size, FT_EE_UAWrite
writes data into it and FT_EE_UARead is used to read its contents.
Download FTDI Application Notes AN_103 and AN_104 for detailed instructions on how to
install the drivers on XP and Vista platforms.
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5.0 EEPROM WRITE UTILITY
The DLP-USB245R has the option to accept manufacturer-specific information that is written
into EEPROM memory. Parameters that can be programmed include the VID and the PID
identifiers, the manufacturer's product string and a serial number.
MPROG is the latest EEPROM programming utility for the FT245R device. You must install the
latest release of the CDM drivers in order to run this application. If you have CDM drivers
installed on the PC that is to perform the EEPROM write process, you can run MPROG and
update the EEPROM contents with either mode (VCP or D2XX) active.
6.0 QUICK START GUIDE
This guide requires the use of a Windows XP/Vista PC that is equipped with a USB port.
Unzip the drivers into a folder on the hard drive.
2. Connect the DLP-USB245R board to the PC via a USB ‘A’ to mini-B cable. This action
initiates the loading of the USB drivers. When prompted, select the folder where the device
drivers were stored in Step 1. Windows will then complete the installation of the device
drivers for the DLP-USB245R module. The next time the DLP-USB245R module is
attached, the host PC will immediately load the correct drivers without any prompting.
Reboot the PC if prompted to do so.
At this point, the DLP-USB245R is ready for use. Note that the DLP-USB245R will appear non-
responsive if data sent from the host PC is not read from the FT245R device by an attached
microcontroller, microprocessor, DSP, FPGA, ASIC, etc.
7.0 PINOUT DESCRIPTION
Pin 18
Pin 1
USB
Pin 10
Pin 9
Top View
(Interface Headers on bottom of PCB)
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PIN # DESCRIPTION
1
2
3
4
5
GROUND
DB2 - FIFO Data Bus Bit 2
DB7 - FIFO Data Bus Bit 7
DB5 - FIFO Data Bus Bit 5
DB3 - FIFO Data Bus Bit 3
PWREN# - Goes low after the module is configured by USB, then high during USB
Suspend. This output can be used to control an external P-channel, logic-level MOSFET
switch. Enable the interface pull-down option when using the PWREN# pin in this way.
PWREN# should be pulled to VCCIO with 10k-Ohm resistor.
VCCIO - +1.8V to +5.25V supply for the FIFO interface. Connect this pin to an external
power supply to drive out at +3.3V levels (or another voltage within the specified range),
or connect to EXTVCC (Pin 8) to drive out at the +5V CMOS level.
EXTVCC - Use for applying main power (4.0 to 5.25 volts) to the module. Connect to
PORTVCC (Pin 9) if the module is to be powered by the USB port (typical configuration).
PORTVCC - Power from the USB port. Connect to EXTVCC (Pin 8) if the module is to
be powered by the USB port (typical configuration). 500mA is the maximum current
available to the USB adapter and target electronics if the USB device is configured for
high power.
6
7
8
9
10
11
GROUND
RD# - When pulled low, RD# takes the 8 data lines from a high-impedance state to the
current byte in the FIFO’s buffer. Taking RD# high returns the data pins to a high-
impedance state and prepares the next byte (if available) in the FIFO to be read.
WR - When taken from a high to a low state, WR reads the 8 data lines and writes the
byte into the FIFO’s transmit buffer. Data written to the transmit buffer is sent to the host
PC within the TX buffer timeout value (default 16mS) and placed in the buffer that was
created when the USB port was opened. The FT245R allows the TX buffer timeout value
to be reprogrammed to a value between 1 and 255mS.
12
13
14
DB6 - FIFO Data Bus Bit 6
TXE# - When high, do not write data into the FIFO. When low, data can be written into
the FIFO by strobing WR high, then low. During reset this signal pin is tri-state. Data is
latched into the FIFO on the falling edge of the WR pin.
RXF# - When low, at least 1 byte is present in the FIFO’s receive buffer and is ready to
be read with RD#. RXF# goes high when the receive buffer is empty. During reset this
signal pin is tri-state. If the Remote Wakeup option is enabled in the internal EEPROM,
during USB Suspend Mode (PWREN#=1) RXF# becomes an input. This can be used to
wake up the USB host from Suspend Mode by strobing this pin low for a minimum of
20ms which will cause the device to request a resume on the USB bus.
DB1 - FIFO Data Bus Bit 1
15
16
17
18
DB4 - FIFO Data Bus Bit 4
DB0 - FIFO Data Bus Bit 0
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8.0 DEVICE CONFIGURATION EXAMPLES
USB Bus-Powered and Self-Powered Configurations
Figure 1.
7
8
9
Bus-Powered
5V System
The figure above illustrates a typical USB bus-powered configuration. A USB bus-powered
device gets its power from the USB bus. Basic rules for USB bus-powered devices are as
follows:
1. On plug-in to USB, the module and external circuitry should draw no more than 100mA on
the 5-volt line from the USB host.
2. In USB Suspend Mode, the module and external circuitry should draw no more than 2.5mA.
3. A bus-powered, high-power USB device (one that draws more than 100mA) should use one
of the CBUS pins configured as PWREN# to keep the current below 100mA on plug-in and
below 2.5mA on USB Suspend.
4. A design that consumes more than 100mA in total cannot be plugged into a USB
bus-powered hub.
5. No USB target system can draw more than 500mA from the USB bus. The power descriptors
in the internal EEPROM of the FT245R should be programmed to match the total current drawn
by the target system.
Note: If using PWREN# (available using the CBUS), the I/O pin should be pulled to VCCIO
using a 10k-ohm resistor.
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Figure 2.
5.0V
7
8
9
Self-Powered
5V System
Figure 2 illustrates a typical USB self-powered configuration. A USB self-powered device gets
its power from its own power supply and does not draw current from the USB bus. Basic rules
for USB self-powered devices are as follows:
1. A self-powered device should not force current down the USB bus when the USB host or hub
controller is powered down.
2. A self-powered device can take as much current as it likes during normal operation and
during USB Suspend as it has its own power supply.
3. A self-powered device can be used with any USB host and both bus- and self-powered USB
hubs.
3.3V
Microcontroller
Figure 3.
8 Data Lines
RXF#
3.3V
RD#
7
8
TXE#
WR
9
Bus-Powered
5V System with
3.3V Logic Interface
Figure 3 shows how to configure the DLP-USB245R to interface with a 3.3V logic device. In this
example, the target electronics provide the 3.3 volts via the VCCIO line (Pin 7) which, in turn,
will cause the FT245R interface I/O pins to drive out at the 3.3V level.
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9.0 BUS-POWERED CIRCUIT WITH POWER CONTROL
USB bus-powered circuits need to be able to power down in USB Suspend Mode in order to
meet the <= 2.5mA total Suspend current requirement (including external logic):
P-Channel
Power MOSFET
Figure 4.
S
D
G
.1uF
10K
1K
Microcontroller
VCC
PWREN#
7
8
9
Power Controlled by
PWREN#
Figure 4 shows how to use a discrete P-Channel MOSFET to control the power to external logic
circuits. This “soft-start” circuit accommodates designs that draw more than 100mA at power
up.
Please note the following points in connection with power-controlled designs:
1. The logic to be controlled must have its own reset circuitry so that it will automatically reset
itself when power is reapplied on coming out of Suspend.
2. Set the soft pull-down option bit in the FT245R EEPROM.
3. For USB high-power, bus-powered applications (ones that consume greater than 100mA,
and up to 500mA of current from the USB bus), the power consumption of the application must
be set in the Max Power Field in the internal FT245R EEPROM. A high-power, bus-powered
application uses the descriptor in the internal FT245R EEPROM to inform the system of its
power requirements.
4. PWREN# gets its VCC from VCCIO. For designs using 3.3-volt logic, ensure that VCCIO is
not powered down during Suspend.
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10.0 MECHANICAL DRAWINGS (PRELIMINARY) INCHES
(MILLIMETERS) UNLESS OTHERWISE NOTED
0.22 typ
(5.6 typ)
0.21 typ
(5.3 typ)
Side View
0.23 typ
(5.8 typ)
0.37 typ
(9.4 typ)
0.43 typ
(10.9 typ)
0.09 typ
(2.3 typ)
0.60 typ
(15.2 typ)
1.26 typ
(32.1 typ)
11.0 DISCLAIMER
© DLP Design, Inc., 2008
Neither the whole nor any part of the information contained herein nor the product described in
this manual may be adapted or reproduced in any material or electronic form without the prior
written consent of the copyright holder.
This product and its documentation are supplied on an as-is basis, and no warranty as to their
suitability for any particular purpose is either made or implied. DLP Design, Inc. will not accept
any claim for damages whatsoever arising as a result of the use or failure of this product. Your
statutory rights are not affected. This product or any variant of it is not intended for use in any
medical appliance, device or system in which the failure of the product might reasonably be
expected to result in personal injury.
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This document provides preliminary information that may be subject to change without notice.
12.0 CONTACT INFORMATION
DLP Design, Inc.
1605 Roma Lane
Allen, TX 75013
Phone: 469-964-8027
Fax:
415-901-4859
Email Sales:
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25
7
18
21
26
AGND
GND
GND
GND
TEST
4
VCCIO
|