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For more interesting projects done by Flameman, be sure to check out his project index

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The Universal USB to Serial breakout board is designed to allow the maximum flexibility for all your serial protocol needs, the FT2232H is specially designed to take advantage of several common serial protocols. The board includes an onboard 3.3V regulator, access to +5 and +3.3V if your project is to run on bus power, and a blank EEPROM for configuration data(such as modes, VID/PID).

The available serial modes are:
- Dual Channel RS232/RS422/RS485                                           
- Dual Channel 245 FIFO - Sync/Async
- Dual Channel JTAG <---------------------- what you need
- Dual Channel I2C
- Dual Channel SPI
- Dual Channel Bit Bang - Sync/Async
- Dual Channel CPU style FIFO Interface
- Dual Combination of any of the above interfaces
- Fast Serial Optical Interface
- 8051 Host Bus Emulation

The datasheet can be downloaded from FTDIChip.com. As well, they have information on all the configuration modes, and custom DLL's for the I2C, SPI, and JTAG interfaces.

In order to use a ft2232 as gnICE usb-jtag, you have to program the onboard EEPROM. FTDI has a program called FT_PROG. Download and run the program and parse the FT2232 information. As you can see from the image, after parsing the data, you need to navigate to the hardware settings under each port and select 245 FIFO mode. Once this is done, write the data to the FT2232 chip. I have noticed that the FTDI_Prog seems to have a bug where string descriptors do not get read back right if you change them. As far as I can tell they write properly, but do not read back correctly and appear as garbled characters.

Analog Devices documentation

ft2232-bfjtag pinout


FT2232H.AD5 --- BFjtag.pin02  EMU
FT2232H.AD3 --- BFjtag.pin06  TMS
FT2232H.AD0 --- BFjtag.pin08  TCK
FT2232H.AC1 --- BFjtag.pin10  TRST
FT2232H.AD1 --- BFjtag.pin12  TDI
FT2232H.AD2 --- BFjtag.pin14  TDO
FT2232H.gnd --- BFjtag.pin04  gnd

     1 -|..|- 2  emu
     3 -|..|- 4  gnd
     5 -|..|- 6  tms
gnd  7 -|..|- 8  tck
gnd  9 -|..|- 10 /trst
gnd 11 -|..|- 12 tdi
gnd 13 -|..|- 14 tdo

ft2232 boards

dangerous project FT2232 breakout board



method1: do a custom configuration, programming the ft2232 eeprom

Every FT2232 universal serial module has an EEPROM (1) on board that is programmed with a default set of parameters including the

  • VID:0x0403 default
  • PID:0x6010 default
  • VID:0x0456 gnICE <------ you need this
  • PID:0xf000 gnICE <------ you need this

The EEPROM can be changed onboard using the FTDI Windows utility FT_Prog or any other Linux stuff. If you change the VID & PID to match gnice then every software looking for gnICE can detect the module.


/CS  Chip Select
SclK Serial Data Clock
DIn  Serial Data Input
DOut Serial Data Output
GND  Ground
/WRP write protect, put to vcc to protect
VCC  Power Supply
ORG  Internal Organization 8/16bit

 /cs -| |_| |- vcc
Sclk -|     |- /wrp
DIn  -|     |- org 8/16bit
DOut -|_____|- gnd


EEPROM configuration

Use this information to build the configuration EEprom for the FT2232H

[Basic Details]
Device Type=5
VID PID Type=2
USB VID=0456
[USB Power Options]
Bus Powered=1
Self Powered=0
Max Bus Power=100
[USB Serial Number Control]
Use Fixed Serial Number=0
Fixed Serial Number=12345678
[USB Remote WakeUp]
Enable Remote WakeUp=0
[Windows Plug and Play]
Enable Plug and Play=1
[USB String Descriptors]
Manufacturer=Analog Devices Inc.
Product=Blackfin gnICE
[Programming Options]
Only Program Blank Devices=1
[BM Device Specific Options]
USB Version Number=1
Disable Serial Number=0
IO Pin Pull Down in Suspend=0
[Dual Device Specific Options A]
RS 232 mode=0
245 FIFO mode=1
245 CPU FIFO mode=0
OPTO Isolate mode=0
High Current Drive=1
[Dual Device Specific Options B]
RS 232 mode=1
245 FIFO mode=0
245 CPU FIFO mode=0
OPTO Isolate mode=0
High Current Drive=1
[Dual Device Driver Options A]
Virtual Com Port Driver=0
D2XX Driver=1
[Dual Device Driver Options B]
Virtual Com Port Driver=1
D2XX Driver=0
[R Device Specific Options]
Invert TXD=0
Invert RXD=0
Invert RTS#=0
Invert CTS#=0
Invert DTR#=0
Invert DSR#=0
Invert DCD#=0
Invert RI#=0
C0 Signal=-1
C1 Signal=-1
C2 Signal=-1
C3 Signal=-1
C4 Signal=-1
Enable Ext Osc=0
High Current I/O=0
Load D2XX Driver=0
In EndPoint Size=0

tools to program the configuration EEprom


You need "FT_prog", download it from the FTDI web, it will figure this way




method2: hacking urjtag

urjtag is handling is at urjtag/src/tap/cable/ft2232.c & ft2232_list.h This is where the gnice and gnice+ are defined.

so you could aldo modify the urjtag code replacing

URJ_DECLARE_FTDX_CABLE(0x0456, 0xF000, "-mpsse", "gnICE", gnice)


URJ_DECLARE_FTDX_CABLE(0x0403, 0x6010, "-mpsse", "gnICE", gnice)

it has been used here: http://www.mindchasers.com/topics/jtag.htm

big image