Matrix Keypad routine

[skimask]

well, i was thinking that when i push "Button A" of the keyapd, the upper setpoint will be displayed, "Button B" = Lower limit, "Button C" = Backspace, "Button D" = OK , "Button *" = alarm on/off, "Button #" = Main screen

Ok, so you've defined the FUNCTIONs of the buttons...now how to you act on those functions.
In fact, do yourself a favor and just work on adding one button at a time...