KEYPAD and Interrupt on Changing PORTB

[mister_e]

Here's something to play with

    DEFINE LCD_DREG PORTA
    DEFINE LCD_DBIT 0
    DEFINE LCD_RSREG PORTA
    DEFINE LCD_RSBIT 4
    DEFINE LCD_EREG PORTE
    DEFINE LCD_EBIT 0
    DEFINE LCD_BITS 4
    DEFINE LCD_LINES 2

    include "keypad.bas"
    
    DEFINE KEYPAD_ROW        4        ' 4 ROW keypad       
    DEFINE KEYPAD_ROW_PORT   PORTB    ' ROW port = PORTB
    DEFINE KEYPAD_ROW_BIT    4        ' ROW0 = PORTB.4
    DEFINE KEYPAD_COL        3        ' 3 COL keypad
    DEFINE KEYPAD_COL_PORT   PORTB    ' COL port = PORTB
    DEFINE KEYPAD_COL_BIT    1        ' COL0 = PORTB.1
    DEFINE KEYPAD_DEBOUNCEMS 50       ' debounce delay = 50 mSec
    DEFINE SCAN_ONCE         1

    OPTION_REG.7=0        ' Enable internal crap pull-up :D
    ADCON1=7              ' disable ADCs
    PORTB = 0             '  
    TRISB = %11110000     '
      
    ByteA var byte        '

    INTCON = %10001000    ' Enable global interrupt
                          ' Enable interrupt on PORTB change
    on interrupt goto KeypadInt
    CLEAR

Init:    
    lcdout $FE,1,"Press any Key"
Start:
    if Bytea then
        LCDOUT $FE,1,"Key=",dec bytea
        bytea=0
        pause 1000
        goto init
        endif
    goto start
    
disable
KeypadINT:    
    @ READKEYPAD _ByteA
    TRISB=%11110000
    PORTB=0
    INTCON.0=0
    resume
enable

you'll find the Keypad.Bas file in attachement. Don't forget to include it in the same directory.

Enjoy