The ClockworkPi R-01 attempts to be compatible with the Pi 3 CM. It mostly succeeds but not 100% as the Pi 3 CM interface has some things that the D1 simply doesn't have, and the D1 has some things that the Pi 3 CM interface doesn't accomodate.
Sipeed now has at two RISC-V "compute modules" that follow the concept but don't attempt to be Pi compatible:
- LicheeRV module, Allwinner D1, same as the R-01, but with two side by side M.2 connectors as the interface. They sell a LicheeRV Dock for it.
- Lichee Module 4A, THead TH1520 SoC. Currently only available as part of Lichee Pi 4A, but they plan to sell the module separately, as well has a motherboard holding a cluster of 7 modules, a tablet, a laptop, maybe a phone. Uses a SODIMM connector.
In addition, Sipeed have a number of other lower powered RISC-V "module" products using K210, BL808, BL702. Most with circuit boards with castellated edges as the connector, some with some kind of edge connector. And some ARM ones too.
