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RISC-V CPU for OpenFPGAs, in Icestudio

Quick start

  • Open the file with Icestudio (5.0 or higher)
  • Connect the Alhambra-II board (or compatible) and upload the design
  • It will take around 6min to sinthesize and upload to the board
  • The system is ready for executing your firmware!

Testing the firmaware in C

  • go to the firmware/soc-demo/src-c folder
  • Execute make (It is assumed that you already have the risc-v tools installed)
  • You should see a binary counter in the LEDs
  • If you open a serial terminal (115200 bauds) you will see messages

  • Pressing the "1" key will reset the counter and show the intial message again

Testing the firmware in asm

  • go to the firmware/soc-demo/src-asm folder
  • Execute make
  • You should see a value in the LEDs


It is based on the picorv32 by Clifford Wolf

SOCs for the RARs simulator

There are two socs for using with the RARs simulador:

  • It have no uart and 1 output port at address 0xFFFF0000, connected to the LEDs
  • The previous soc plus one additional output port, connected to the D0-D7 pins in the Alhambra II board

In the firmware/soc-rars-MMIO-1/rars and firmware/soc-rars-MMIO-2/rars folderS there are examples for trying. Open them with the RARs simulator, assemble and dump the code into a .bin file. Then flash it into the FPGA with iceprog tool:

iceprog -o 1M file.bin