[bsder]

Emulating the RPI PIOs instead of the TI PRUs is really a miss.

The PRUs really get a bunch right. Very specifically, the ability to broadside dump the ENTIRE register file in a single cycle from one PRU to the other is gigantic. It's the single thing that allows you to transition the data from a hard real-time domain to a soft real-time domain and enables things like the industrial Ethernet protocols or the BeagleLogic, for example.

[aa-jv]

Tooling for the RPI PIO design is probably a bit more accessible than the TI PRU situation. I'd say its not really a miss - more of a necessity given bennies' proclivity towards open/available tools. Getting access to architecture details of the TI PRU would necessitate an NDA, would it not?

[bsder]

> Getting access to architecture details of the TI PRU would necessitate an NDA, would it not?

Nope. All the information is right in the publicly available architecture manuals. However, you don't need to copy the PRUs, per se. All this can be done with RISC-V.

The important parts are deterministic execution, the register file sideload between paired processors, and, possibly, single cycle instruction execution. None of these are precluded by using RISC-V.

And, given how large his PIO stuff is, I'd argue it would be better to do this with RISC-V.