picorv32/scripts/icestorm/readme.md

To build the example LED-blinking firmware for an HX8K Breakout Board and get a timing report (checked against the default 12MHz oscillator):

$ make clean example.bin timing

To run all the simulation tests:

$ make clean example_sim synth_sim route_sim FIRMWARE_COUNTER_BITS=4

(You must run the clean target to rebuild the firmware with the updated FIRMWARE_COUNTER_BITS parameter; the firmware source must be recompiled for simulation vs hardware, but this is not tracked as a Makefile dependency.)