WCH Link RV USB protocol

Read version

Req:81(host to link) 0d 01 01
Resp:82(link to host) 0d 02 02(major) 01(minor)

Read status

Req:81(host to link) 0d 01 02
Resp(error):81(host to link) 55 01 01
Resp(correct):82(link to host) 0d 02 01(chip type?) 00

?

Req:81(host to link) 0d 01 03
Resp:82(link to host) 0d 01 03

DMI Read

Req:81(host to link) 08 06 11(DMI reg 0x11) 00 00 00 00(always 0?) 01(00:nop 01:read 02:write)
Resp:82(link to host) 08 06 11(DMI reg 0x11) 12 34 56 78 (read value 0x12345678) 00(status)

DMI Write

Req:81(host to link) 08 06 11(DMI reg 0x11) 12 34 56 78(write value 0x12345678) 02(00:nop 01:read 02:write)
Resp:82(link to host) 08 06 11(DMI reg 0x11) 12 34 56 78 (written value is 0x12345678) 00(status)