I don't understand why you've placed the 'z' handling code in "printDigits", where INBYTE cannot possibly be 'z' (as far as I can see).
Why not put the text handling stuff in a different function, and call that from "loop()" if INBTYTE is a 'z'?
I don't understand why you've placed the 'z' handling code in "printDigits", where INBYTE cannot possibly be 'z' (as far as I can see).
Why not put the text handling stuff in a different function, and call that from "loop()" if INBTYTE is a 'z'?