I'm bot sure exactly how open this is, and how good the documentation is, but maybe the Core V MCU devkit [0]? This is very new, so I'd probably wait a bit for it to mature.
It's uses the open source CV32E40P RISC-V core (in-order 4-stage RISC-V RV32IMFCXpulp)
> It’s probably the most “open-source hardware” board we’ve covered so far, since not only the hardware design files and SDK are open-source, but also the MCU core used in the CORE-V MCU. [1]
It's uses the open source CV32E40P RISC-V core (in-order 4-stage RISC-V RV32IMFCXpulp)
> It’s probably the most “open-source hardware” board we’ve covered so far, since not only the hardware design files and SDK are open-source, but also the MCU core used in the CORE-V MCU. [1]
[0] https://www.openhwgroup.org/core-v-devkits/
[1] https://www.cnx-software.com/2023/08/04/core-v-mcu-devkit-fe...