Live data from Hacker News

PicoRio Linux RISC-V SBC is an open-source alternative to Raspberry Pi board

cnx-software.com

1–10 of 159 posts

Re: PicoRio Linux RISC-V SBC is an open-source alternative to Raspberry Pi board

#2
Promising hardware, though this isn't looking like comparable hardware even to the Raspberry Pi Zero. Only has a quad-core 64-bit RISC-V (RV64GC) processor at 500+ MHz. RAM size not specified. If it was priced in the $5-15 range it would be more or less practical, but higher than that I'd be buying it solely for the architecture novelty.

Re: PicoRio Linux RISC-V SBC is an open-source alternative to Raspberry Pi board

#5
post #3

Oof, GPU by Imagination Technologies. Here's hoping their close brush with death opened them to the idea of open sourcing their code.

>> Oof, GPU by Imagination Technologies.

My first thought as well. On the other hand... baby steps. We need a chip like this very much. If the first ones are slow or too proprietary that may be OK, it is still pushing the RISC-V ecosystem in the right direction. It will help validate a lot of software which will enable more open designs by having things ready to go.

Re: PicoRio Linux RISC-V SBC is an open-source alternative to Raspberry Pi board

#6
It looks like it has some details on "slow" i/o like UART and I2C, but not sure if that counts things like analog PWM timers for certain pins, like there are on RPis. Does anyone have any more information on that? You can do it all in software on a UART, but I think that can be a little more tricky. Since so many basic embedded projects can be helped with that kind of functionality, it would be awesome if it was available.

Re: PicoRio Linux RISC-V SBC is an open-source alternative to Raspberry Pi board

#7
One of the comments I made to myself was that on the die shots, USB3 part is as big as a CPU core ! What would need so much silicon ? Isn't USB3 hardware more or less a serial bus? Is it logic or memory or analog interface parts here? I am curious.

Re: PicoRio Linux RISC-V SBC is an open-source alternative to Raspberry Pi board

#8
post #7

One of the comments I made to myself was that on the die shots, USB3 part is as big as a CPU core ! What would need so much silicon ? Isn't USB3 hardware more or less a serial bus? Is it logic or memory or analog interface parts here? I am curious.

It has to implement all the old versions of USB too

Re: PicoRio Linux RISC-V SBC is an open-source alternative to Raspberry Pi board

#9
post #7

One of the comments I made to myself was that on the die shots, USB3 part is as big as a CPU core ! What would need so much silicon ? Isn't USB3 hardware more or less a serial bus? Is it logic or memory or analog interface parts here? I am curious.

There's a great deal of communication that happens outside the operating system, and a bunch of different multiplexing modes and things like that. There's at least 4 different speeds it's going to need to talk at (1.5mbps, 12mbps, 480mbps, and 5gbps) with a good deal of synchronization and other bits. There's a rather decent amount of logic that has to be implemented, and I wouldn't be shocked if you end up needing what basically amounts to another CPU for the controller itself to manage the entire connection and negotiation. Depending on the physical construction it might also need some decent power transistors if it's also handling the 2 amp current limit on usb3.0 internally (rather than signalling ones outside the chip).

Re: PicoRio Linux RISC-V SBC is an open-source alternative to Raspberry Pi board

#10
post #2

Promising hardware, though this isn't looking like comparable hardware even to the Raspberry Pi Zero. Only has a quad-core 64-bit RISC-V (RV64GC) processor at 500+ MHz. RAM size not specified. If it was priced in the $5-15 range it would be more or less practical, but higher than that I'd be buying it solely for the architecture novelty.

It's still a decent start, and I'm hoping future versions will begin open sourcing the rest of the chip core like the memory controller. It'd be nice to have a good DDR IP core for things like this.

EDIT: Removed a bit of the comment from a misunderstanding from reading the article

Post reply on HN