Hacker News Reader

Comment by sylware | Hacker News Reader

I wish the RP2350 would include a fuse to disable for good the ARM cores for those who want only the risc-v cores (and maybe not pay ARM royalties on those chips).

View on HN

See pg.1259 in the datasheet, the ARM_DISABLE fuse does exactly that. Putting that in was a smart move because it means they can always make a RISC-V-only variant of the chip without having to tape out new silicon - they just have to blow that fuse at the factory.

I'm not sure "arm-core-disabled-by-fuse" is gonna be sufficient to persuade arms legal department to stop charging royalties...

That's actually a super common way to handle licensing in hard IP. You don't want to spin different revisions of a chip with and without the IP, that's expensive. So you build in fuses to permanently disable the IP. This happens a lot with hardware video encoder/decoder blocks.

Or you do it the other way around in software - remember the Pi 1/2 era where you had to buy separate licenses for MPEG/h264 HW decoders, tied to the Pi's serial number?

That's why the fuse, with proper sales accounting, is so much important.

Good!

Upon buying a board with a RP2350, do you know of a reseller who burns the fuse before shipping it to you (and don't pay ARM royalies on that sale)?

Maybe this is just not the microcontroller you are looking for?

One imagines that at some point they will release a pure risc-v chip, once community adoption of the new RP2350 cores is widespread.

It means the chip CPU cores won't be tied to ARM PI enforcement, and won't have to pay for the license to implement ARM ISA (or implement ARM core design).

So no words about Cadence-Synopsys duopoly? ARM bad lazy, that's it?

Rome was not built in one day.

Yes, correct.

Reply on news.ycombinator.com