Working exhubris demo on Raspberry Pi Pico 2(W) board

[Karthik-d-k]

Hi everyone,

I created this discussion to share my progress on bringing hubris/exhubris to the new Pico 2 W board.

I’ve been working with the exhubris repo for the past few weeks, with the ultimate goal of porting Hubris to support the RISC-V core on the Pico 2 W board.

This board is especially exciting because it comes with dual Cortex-M33 cores and dual RISC-V Hazard3 cores. My approach was to start with the Cortex-M33 side first, since Hubris already has solid ARM support.

I’m happy to share that I now have a working demo running a blinky task, toggling an external LED connected to GPIO22 🎉.
You can check it out here: exhubris-demo-rp235x.

A couple of notes:

• To flash using humility, you’ll need to install the version from @thenewwazoo humility port: humility/tree/bmatt/update-probe-rs, which includes an updated probe-rs with Pico 2 W support.
• If you’d like to see the Hubris variant of the same app (also working), I’ve published it here: hubris-riscv-hazard3/tree/cortex-m33. This is based on @thenewwazoo’s excellent work in hubris/tree/bmatt/rp2350, with my blinky task added alongside his idle and jefe tasks.

As mentioned, my final goal is to get this same demo running on the Hazard3 RISC-V core. I’ve been experimenting with both the Hubris and exhubris repos for this porting effort, each has its pros and con, but since I now have a working demo on both, I’m leaning towards exhubris because of its simpler build system.

For those curious, my current (non-working, hacky) RISC-V attempts are here:

• hubris-riscv-hazard3/tree/riscv
• exhubris-riscv-hazard3/tree/riscv

UPDATE:
I’ve written a brief post that explores the details further.
hubris-on-pico2

I’d love to hear any feedback, ideas, or suggestions if any :)

Thank you

[thenewwazoo]

This is great stuff! I'm glad my work was useful.

Because there are infinite yaks and I must shave them all, I'm actually working on a port of nusb to illumos, so that I can submit my humility updates upstream.

[Karthik-d-k]

UPDATE:

Got the same demo running on the Hazard3 RISC-V core 🥳

• Application: exhubris repo
• Kernel: hubris repo
• Full write-up is available here hubris-on-pico2-riscv