Hi
fun as it would be to get into a pissing contest with ARM and have all the claims invalidated by crowd-sourced prior art searches like cloudfare did against that patent troll last year, we have better things to do with our time.
For a SoC without any ARM IP I agree with David it's best to stay away from using AMBA bus. Even if a law suit would/could be won it's a real PITA.
Ok. Then we're on the same page here. Because PicoRV32 is using the axi bus as well, we can't use this core for our MCU/SoC either. We will have to bootstrap our own SoC/MCU using Chisel3 and rocket-chip as a basis, essentially stripping the rocket-chip of all AXI-stuff and re-adding the features, but hooked up directly over TileLink instead. I guess the only reason eFabless with their Raven didn't get into trouble yet is because there were just some managers at ARM hysterically laughing when they've read the tape out volume and orders of this MCU. But as soon as we start providing a free technology node and open layout and sell the part as off-the-shelf part they might become pretty nasty and try to hurt us any way they can, including law-suits (even though futile, as we've all determined)
Cheers David