KEYPAD and Interrupt on Changing PORTB

'****************************************************************
'*  Name    : PORTB_CHANGE.BAS                                  *
'*  Author  : Mostafa Taghavi Kani                              *
'*  Notice  : Copyright (c) 2006 Embedded Technology            *
'*          : All Rights Reserved                               *
'*  Date    : 2006/12/14                                        *
'*  Version : 1.0                                               *
'*  Notes   :                                                   *
'****************************************************************

'include "modedefs.bas"

define  OSC 4


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

GIE     VAR  INTCON.7
PEIE    VAR  INTCON.6
T0IE    VAR  INTCON.5
INTE    VAR  INTCON.4
RBIE    VAR  INTCON.3
T0IF    VAR  INTCON.2
INTF    VAR  INTCON.1
RBIF    VAR  INTCON.0

RBPU    VAR  OPTION_REG.7
INTEDG  VAR  OPTION_REG.6
T0CS    VAR  OPTION_REG.5
T0SE    VAR  OPTION_REG.7
PSA     VAR  OPTION_REG.3
PS2     VAR  OPTION_REG.2
PS1     VAR  OPTION_REG.1
PS0     VAR  OPTION_REG.0

i       VAR  BYTE
'PORTB   VAR  BYTE[3]
x       VAR  BYTE
ROW     VAR  BYTE
COL     VAR  BYTE
J       VAR  BYTE
R       VAR  BIT
C       VAR  BIT

TRISB=%11110000 : 'PORTB=%11111111
TRISD=%00000000
i=0

'OPTION_REG=%01010111       'ONLY FOR CAMPACTING THE PROGRAM
INTCON = %10001000
RBPU=0

ON INTERRUPT GOTO TEST

MAIN:
'    PORTD=$FF
'    PAUSE 200
'    PORTD=$00
'    PAUSE 500
    IF I==0 THEN
        LCDOUT $FE,1,"PRESS ANY KEY!"
    ELSE
        LCDOUT $FE,1,"(ROW,COLUMN)=","(",#R,",",#C,")"
    ENDIF

    PORTB=(PORTB & %11110010)
'    PAUSE 20
    PORTB=(PORTB & %11110100)
'    PAUSE 20
    PORTB=(PORTB & %11111000)
'    PAUSE 20
'    FOR J=1 TO 3
'        PORTB=%00000001
'        PORTB=PORTB << 1
'    NEXT J
'    WHILE(J)
'            J
    GOTO MAIN

DISABLE
TEST:
    @ MOVF PORTB,W  'IMPORTANT:reads PORTB and moves the value to W register!!! 
'   @ MOVE?BA PORTB  'another ALTERNATE for above line!
    ROW=(PORTB & %11110000)
    COL=(PORTB & %00001110)
    SELECT CASE ROW
           CASE %00010000
                R=1
           CASE %00100000
                R=2
           CASE %01000000
                R=3
           CASE %10000000                
                R=4
    END SELECT
    
'    FOR K=1 TO 3
'        IF COL.K=1
'    NEXT K

    SELECT CASE COL
           CASE %00000010
                C=1
           CASE %00000100
                C=2
           CASE %00001000
                C=3
    END SELECT
    i=i+1
'    LCDOUT $FE,1,"PORTB CHANGES=",#I
    RBIF=0
'   PORTD=$00
    RESUME
ENABLE


END