SCANNING THE KEYPAD, input from keypad PIC Assembly

Sun May 19, 2013 1:46 pm

Code:: TITLE "SCANNING THE KEYPAD" list p = 16f877 include <p16f877.inc> BANK0 macro bcf STATUS,RP0 bcf STATUS,RP1 endm BANK1 macro bsf STATUS,RP0 bcf STATUS,RP1 endm BANK2 macro bcf STATUS,RP0 bsf STATUS,RP1 endm BANK3 macro bsf STATUS,RP0 bsf STATUS,RP1 endm ;* DELAY_TIME EQU 0x20 KEYDATA EQU 0x21 TEMP EQU 0x22 ;**** ORG 0 NOP GOTO START ;*** ; MAIN ROUTINE ORG 0x20 START CALL INIT ;INITIALISE PORTS AGAIN MOVLW 1 ;SET ROW 1 HIGH MOVWF PORTD ;AND OUTPUT BTFSS PORTD,7 ;TEST COLUMN 1 No 3 GOTO SIX ;IF NOT 3, TRY 6 MOVLW 3 ;ELSE STORE 3 MOVWF KEYDATA ;IN KEyDATA GOTO LAST ;AND FINISH SIX BTFSS PORTD,6 ;TEST COLUMN 1 No € GOTO NINE ;IF NOT 6, TRY 9 MOVLW 6 ;ELSE STORE 6 MOVWF KEYDATA ;IN KEyDATA GOTO LAST :AND FINISH NINE BTFSS PORTD,5 ;TEST COLUMN 1 No 5 GOTO NUM ;IF NOT 5, TRY NUM * MOVLW 9 ;ELSE STORE 9 MOVWF KEYDATA ;IN KEyDATA GOTO LAST ;AND FINISH NUM BTFSS PORTD,4 ;TEST cOLUMN 1 NUM * GOTO COL2 ;IF NOT NUM, TRY COL 2 MOVLW 0FFH ;ELSE SToRE FFH MOVWF KEYDATA ;IN KEyDATA GOTO LAST ;AND FINISH COL2 MOVLW 2 ;SET ROW 2 HIGH MOVWF PORTD ;AND OUTPUT BTFSS PORTD,7 ;TEST COLUMN 2 No 2 GOTO FIVE ;IF NOT 2, TRY 5 MOVLW 2 ;ELSE STORE 2 MOVWF KEYDATA ;IN KEyDATA GOTO LAST ;AND FINISH FIVE BTFSS PORTD,6 ;TEST COLUMN 2 No 5 GOTO EIGHT ;IF NOT 5, TRY MOVLW 5 ;ELSE SToRE 5 MOVWF KEYDATA ;IN KEYDATA GOTO LAST ;AND FINISH EIGHT BTFSS PORTD,5 ;TEST COLJMN 2 No 8 GOTO NONE ;IF NOT 8, TRY 0 MOVLW 8 ;EISE STORE 8 MOVWF KEYDATA ;IN KEYDATA GOTO LAST ;AND FINISH NONE BTFSS PORTD,4 ;TEST COIIJMN 2 No 0 GOTO COL3 ;IF NoT ZERo, TRy CoL 3 MOVLW 0 ;ELSE SToRE 0 MOVWF KEYDATA ;IN KEYDATA GOTO LAST ;AND FINISH C0L3 MOVLW 4 ;SET RoW 3 HIGH MOVWF PORTD ;AND OUTPUT BTFSS PORTD,7 ;TEST cOLJw’iN 3 No 1 GOTO FOUR ;IF NoT 1, TRy 4 MOVLW 1 ;ELSE SToRE 1 MOVWF KEYDATA ;IN KEYDATA GOTO LAST ; AND FINISH FOUR BTFSS PORTD,6 GOTO SEVEN MOVLW 4 MOVWF KEYDATA GOTO LAST SEVEN BTFSS PORTD,5 ;TEST COLJ 3 No 7 GOTO STAR ;IF NOT 7, TRY MOVLW 7 ;ELSE SToRE 7 MOVWF KEYDATA ;|IN KEYDATA GOTO LAST ;AND FINISH STAR BTFSS PORTD,4 ;TEST COLJMN 3 ‘ GOTO LOOP ;IF NOT a, TRY REPEAT MOVLW 0FFH ;ELSE SToRE FF11 MOVWF KEYDATA ;IN KEYDATA GOTO LAST ;AND FINISH LAST CALL DELAY ;DEBoUNDz KEYPAD LOOP MOVF PORTD,W ;READ PORT ANDLW 0F0H ;MASK OL5 BTFSS STATUS,Z ;AND WAIT TILL No PRESSED GOTO LOOP GOTO AGAIN ;Do AGAIN ; PORT INTIAlISATION INIT BANK1 ;SET To BANK 1 MOVLW 0xF0 ;SET BITS 0-3 AS oUT, 4-7 AS IN MOVWF TRISD BANK0 ;BACK To BANK 0 RETURN ; DELAy RotJTIN DELAY MOVWF TEMP ;SAvE W MOVLW 0xFF MOVWF DELAY_TIME WAIT INCFSZ DELAY_TIME GOTO WAIT MOVF TEMP,W RETURN END