chmousset / icetag

using icestick as FT2232 JTAG interface

ICETAG - using icestick as JTAG adapter

Goal

The icestick is a simple, inexpensive FPGA dev board with an onboard FT2232H. The FT2232H has two MPSSE ports that can act as UART, JTAG, FIFO or SPI interfaces. This project allows to use an icestick as an JTAG+UART interface.

Pinout

       ______________________________________
      /                  o o o o o o o o o o |
   __/           _________    | 3V3 | 3V3 |  |
 _____          |         |   | GND | GND |  |
|     |         |         |   |  7  |  3  |  |
| USB |         |  ICE40  |   |  6  |  2  |  |
|_____|         |         |   |  5  |  1  |  |
   __           |_________|   |  4  |  0  |  |
     \               J3 10 9 8 7 6 5 4 3 2 1 |
      \______________________________________|

J3	JTAG	SPI	UART
10	TCK	CLK
9	TDI	MOSI
8	TDO	MISO
7	TMS	CS
6	RST
5			TX
4			RX
3
2	GND
1	3V3

Usage

openFPGALoader

openFPGALoader can be used to configure and flash FPGAs with option -c ft2232_b

openFPGALoader -c ft2232_b <other options>

FlashROM

FlashROM can be used to read / program SPI FLASH chips. Here is how to use it with icetag:

flashrom -p ft2232_spi:type=2232H,port=B,divisor=8

you might want to try different divisor value depending on your board.

(optional) Enabling the UART

The FT2232 has an EEPROM attached which stores some configuration parameters. By default, the MPSSE port A is configured as a FIFO which can apparently prevents Linux from using is correctly as an UART.

Unfortunately, the only fix for this issue it to re-program the EEPROM with FTDI-s FT-PROG tool, which is windows-only :( Or remove the EEPROM :)

2 configurations are provided in ftprog/ directory:

• icestick_default_ftdi_config.xml : the default configuration
• icestick_2uart_ftdi_config.xml : dual UART-capable configuration

ftdlib also has a ftdi_eeprom utility that seems to be able to read/write the EEPROM, altough it was not verified to be functional. You can try this:

cd ftprog
git clone https://github.com/nblock/libftdi.git
cd libftdi
cmake .
make
cd ..
./libftdi/ftdi_eeprom/ftdi_eeprom --write-eeprom ftdi_eeprom_2uart.conf