' Name        : KEYXU.pbp
' Compiler    : PICBASIC PRO Compiler 2.6
' Assembler   : MPASM
' Target PIC  : PIC18F4550 or similar type
' Hardware    : LAB-XUSB Experimenter Board
' Oscillator  : 20MHz external
' Keywords    : DCD, LCDOUT, NCD
' Description : PICBASIC PRO program to display key number on LCD.
'

' Define LOADER_USED to allow use of the boot loader.
' This will not affect normal program operation.
Define LOADER_USED 1

' RESET_ORG can be set to move the BASIC program out of the way
' of any boot loader running from location 0, such as the
' Microchip USB boot loader
'Define RESET_ORG 800h

Define OSC 48      ' Core is running at 48MHz

' Define LCD pins
Define LCD_DREG  PORTD
Define LCD_DBIT  4
Define LCD_RSREG PORTE
Define LCD_RSBIT 0
Define LCD_EREG  PORTE
Define LCD_EBIT  1

' Define program variables
col Var Byte   ' Keypad column
row Var Byte   ' Keypad row
key Var Byte   ' Key value

   INTCON2.7 = 0        ' Enable PORTB pullups
   ADCON1 = 15          ' Make PORTA and PORTE digital
   Low PORTE.2          ' LCD R/W low (write)
   Pause 100            ' Wait for LCD to start

   Lcdout $fe, 1, "Press any key"  ' Display sign on message

mainloop:
   Gosub getkey         ' Get a key from the keypad
   Lcdout $fe, 1, #key  ' Display ASCII key number
   Goto mainloop        ' Do it forever

' Subroutine to get a key from keypad
getkey:
   Pause 50                ' Debounce

getkeyu:
   ' Wait for all keys up
   PORTB = 0               ' All output pins low
   TRISB = $f0             ' Bottom 4 pins out, top 4 pins in
   If ((PORTB >> 4) != $f) Then getkeyu ' If any keys down, loop
   Pause 50                ' Debounce

getkeyp:
   ' Wait for keypress
   For col = 0 to 3           ' 4 columns in keypad
     PORTB = 0                ' All output pins low
     TRISB = (dcd col) ^ $ff  ' Set one column pin to output
     Pauseus 1
     row = PORTB >> 4         ' Read row
     If row != $f Then gotkey ' If any keydown, exit
   Next col
   Goto getkeyp               ' No keys down, go look again

gotkey: ' Change row and column to key number 1 - 16
   key = (col * 4) + (ncd (row ^ $f))
   Return                     ' Subroutine over

   End