PicoRV32 example?

[sunnystormy]

Hello! I've still got my BlackIce-II board and am trying to get Clifford Wolf's PicoRV32 running on it. I'm running into some problems with getting next-pnr to create an "hx4k" pathway (I know that the tutorials recommend arachne-pnr, but that seems to have been deprecated).

If you have any recommendations for getting a risc-v core running on the board, I'd love to hear it! Thank you for your help!

[lawrie]

--hx8k --package tq144:4k

works for me.

[sunnystormy]

So, I've modified the Makefile that comes with picorv32 to include the options you've provided, and I end up with:

nextpnr-ice40 --hx8k --package tq144:4k --json synth.json --pcf example.pcf --asc example.asc
Info: Importing module top
Info: Rule checker, verifying imported design
Info: Checksum: 0x6c59d296

ERROR: package does not have a pin named 'J3' (on line 1)
ERROR: Loading PCF failed.
0 warnings, 2 errors
make: *** [Makefile:35: example.asc] Error 255

Any idea why this is happening? Is it because the pcf file may have the wrong pin configuration?

Thank you for your help!

---EDIT---
I see that the issue has to do with the default constraints that come with the picorv32 source. I'll have to edit things... >_>

[lawrie]

Yes, you were using the wrong pcf file for the Blackice II board.

Another problem you will get trying to run the hx8kdemo version of PicoSoC on the Blackice II board is that the Blackice board does not have flash memory.

For the Blackice II board, you either need a version that runs entirely from BRAM or one the runs from SRAM like BlackSoc - https://github.com/lawrie/icotools/tree/master/icosoc

Here is a version that runs from BRAM on the Blackice Mx board. You would need to change the pcf file for that version to run on the Blackice II - https://github.com/lawrie/pico_ram_soc

Another problem you will get is that the 100Mhz clock on the Blackice II is too fast to run PicoSoc and you will need to use a PLL or a clock divider. It will probably run at 50Mhz, definitely at 25MHz.

You are better off discussing these things on the mystorm forum than here - https://forum.mystorm.uk/

[sunnystormy]

@lawrie Thank you for this! I'll move the conversation to a more appropriate venue, as per your suggestion.