3 ms·

Is anyone aware of a manufactured and distributed fully open-source risc-v CPU? Maybe one using skywater-pdk

gchadwick 6y ago
Take a look at the projects going into the skywater-pdk shuttle https://efabless.com/open_mpw_shuttle_project_mpw_one https://efabless.com/open_mpw_shuttle_project_mpw_one there are multiple RISC-V CPUs. Manufacturing is currently in progress. 'Distributed' is the tricky point, what counts as 'Distributed' in your eyes? The Skywater MPW is producing ~50 devices for each project I think, I'm sure some of those containing RISC-V CPUs will be distributed around to a few people but there won't be easy general availability of just being able to buy one.
- baybal2 6y ago
  Skywater can do much more, but the stupid "harness" eats tons of space, a majority of it.
  - gchadwick 6y ago
    > but the stupid "harness" eats tons of space, a majority of it. I can't blame them for wanting the harness. By having a constant across everything that tapes-out where there are issues with dead or partially working chips it should be easier to track down what's going wrong. The specific project or something more general with the library, process or tools. There's lot of designs from people new to ASIC flows or without much experience in them, the harness allows efabless to help support people with bring-up. Yes for an experienced ASIC designer it may be an annoyance but you are getting entirely free tape-outs of this. If you want to pay efabless or another company for a tape-out you can do your own thing with skywater PDK. As for the majority of space are you sure? Take this project with layout photo: https://efabless.com/projects/34 https://efabless.com/projects/34 to my eye the 'project' area which is the larger of the two distinct rectangular regions (the bottom smaller one is the harness) looks to be getting the lion's share of the area.
  - deleted 6y ago
    [deleted]

Take a look at the projects going into the skywater-pdk shuttle https://efabless.com/open_mpw_shuttle_project_mpw_one https://efabless.com/open_mpw_shuttle_project_mpw_one there are multiple RISC-V CPUs. Manufacturing is currently in progress. 'Distributed' is the tricky point, what counts as 'Distributed' in your eyes? The Skywater MPW is producing ~50 devices for each project I think, I'm sure some of those containing RISC-V CPUs will be distributed around to a few people but there won't be easy general availability of just being able to buy one.

baybal2 6y ago
Skywater can do much more, but the stupid "harness" eats tons of space, a majority of it.
- gchadwick 6y ago
  > but the stupid "harness" eats tons of space, a majority of it. I can't blame them for wanting the harness. By having a constant across everything that tapes-out where there are issues with dead or partially working chips it should be easier to track down what's going wrong. The specific project or something more general with the library, process or tools. There's lot of designs from people new to ASIC flows or without much experience in them, the harness allows efabless to help support people with bring-up. Yes for an experienced ASIC designer it may be an annoyance but you are getting entirely free tape-outs of this. If you want to pay efabless or another company for a tape-out you can do your own thing with skywater PDK. As for the majority of space are you sure? Take this project with layout photo: https://efabless.com/projects/34 https://efabless.com/projects/34 to my eye the 'project' area which is the larger of the two distinct rectangular regions (the bottom smaller one is the harness) looks to be getting the lion's share of the area.
- deleted 6y ago
  [deleted]