The BLE/HID_Keyboard example from the openwch/ch592 EVT, in its own repo, with a Makefile and a shell.nix added so it's easier to build without needing MounRiver Studio.
The shell.nix uses the nix package manager, and provides the MounRiver toolchain, as well as the newer riscv-none-elf-gcc xpack toolchain, and wchisp. Enter the nix shell using either nix-shell, or nix develop if using nix flakes.
If not using nix, download either MounRiver, or a more recent xpack of riscv-none-elf-gcc.
Run the Makefile using make.
The firmware can be flashed to the CH592 using wchisp. (Enter the CH592 bootloader by holding down BOOT when connecting it using USB).
The SDK for CH592 from the openwch EVT is vendored under sdk/. (Encoding has been changed from gbk to utf-8).