CH57X & CH58X & CH59X

BLE MCUs. They are sharing almost the same preipheral set

Debug Pins

Enable debug using WCHISPTool
Always specify chip type using --chip xxx parameter during connect, auto-detection mechanism does not work on these targets
Similiarly, use -c "chip_id CH59x" while using official OpenOCD release from MRS, as there’s no way to know the chip type before connecting to it
After debug enabled, flash should be prgrammed at lease once
a9 bd f9 f3 means erased flash or protected flash. The detailed mechanism is unknown