/* Command 4 == get input state, returns port 2 and port3 data
* S Addr W [A] len=2 [A] cmd=4 [A]
* RS Addr R [A] [len=4] A [cmd=4] A [port2] A [port3] N P
/* Command 4 == get input state, returns port 2 and port3 data
* S Addr W [A] len=2 [A] cmd=4 [A]
* RS Addr R [A] [len=4] A [cmd=4] A [port2] A [port3] N P