Hacker News Reader

Comment by sydthrowaway | Hacker News Reader

Ah damn. Would you say synthesising a RISC-V CPU on a FPGA dev board would qualify as an alternative?

FPGA dev boards aren't that cheap, particularly one that can synthesize a 64 bit multi-core RISC-V CPU (in fact, there is one that can do it and it costs nearly $3000). The other problem with synthesized CPUs is that the clock speeds are very slow, unless you pay a great deal of money for the FPGA.

They're a lot of fun though - I have PicoRV32 in a very low end Lattice FPGA which cost, like $30 I think? It can only run single C programs, not even an embedded kernel, but I love playing around with it.

Get a large fabric Xilinx FPGA from ebay, reball it and make a simple PCB with Altium auto routing with JTAG, SPI flash, some memory. And find a license for Vivado.

You may not need a new PCB, there are systems with a big FPGA [1] that could make a good host for a RISC-V design.

[1] https://news.ycombinator.com/item?id=21303446

That’s a Spartan 6 but you really want the larger fabric parts. If you go to Digikey they will quote starting at 20k, but on ebay a few hundred will do assuming you have a Vivado license capable of building a bitstream. It is possible to commandeer a board as in that post but often not worth the time vs just making your own. Rarely prototypes with only the power distribution and JTAG appear. Those are a bit easier. Like this https://www.ebay.com/itm/114784061306?hash=item1ab9a9c77a:g:...

That board looks like it might have been a prototype of a Fusion-io card. Compare:

https://commons.wikimedia.org/wiki/File:SanDisk_Fusion_ioMem...

It's basically useless for SoC development, though, as there's no memory on board, no I/Os other than PCIe, and no practical way to add any.

The GPIO is broken out all over the PCB for the NAND. It doesn’t get easier than that

Reply on news.ycombinator.com