Bonus: ice40 Programming

Video demonstration is WIP

The Lattice iCE40 family of FPGAs are popular for small scale projects because of their low cost and the availability of an open toolchain. While this is a very specific target, Tigard is well suited for programming devices since it has all the necessary pins readily available.

Hookup:

All the necessary pins are on the JTAG header. The bonus “!?” pin is not populated by default. The JTAG !? pin and the UART RX pin are shorted in case you need to flash an iCE40 but don’t want to solder your Tigard. See the pinouts table below for details.

Be sure to select JTAG/SPI on the mode selection switch. This makes sure that COPI and CIPO are separated.

If you are planning on programming SRAM instead of FLASH:

• Swap COPI and CIPO
• Disconnect CS from your FLASH, but leave it attached to the iCE40.

Software:

To program your target’s nonvolatile FLASH, use iceprog:

iceprog -I B yourbitstream.bin

If you prefer to directly program the ice40’s SRAM, make sure you adjust your wiring and again use iceprog:

iceprog -I B -S yourbitstream.bin

Remember that if you choose to program the SRAM, your bitstream will be lost on power cycle.