Sorry, this is hastily done due to time constraints right now. Will be fleshed out with more info soon.
Port B clock must be driven in order to avoid odd behaviour. Either put a jumper on the Port B Clock pins, or ensure Clock2 pin on extended bus is being driven from Dual Clock Module.
- SIOA_D .EQU $81
- SIOA_C .EQU $80
- SIOB_D .EQU $83
- SIOB_C .EQU $82