MULTIPLEXING Seven SEGMENT DECODER Assembly

Sat May 18, 2013 11:18 pm

MULTIPLEXING SEVEN SEGMENT DECODER In order to display multi-digit number.

Code:: TITLE "MULTIPLEXING 7 SEGMENT DECODER" 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 ; **** EQUATES DIGIT1 EQU 0x20 DIGIT2 EQU 0x21 DIGIT3 EQU 0x22 DIGIT4 EQU 0x23 COUNT EQU 0x24 DIGIT EQU 0x25 TEMP EQU 0x26 DELAY_TIME EQU 0x27 DATAVALUE EQU 0; INDIRECT ADDRESS ; ****** ORG 0 NOP GOTO START ; MAIN ROUTINE ORG 0x20 START CALL SET_DATA CALL INIT ;INITIALISE PORTS AGAIN MOVLW 4 ;SET CoUNT = 4 MOVWF COUNT MOVLW 0x20 ;SET PoINTER To DATA MOVWF FSR ;AND STORE MOVLW 8 ;SET DIGIT To MSB MOVWF DIGIT ;AND STORE NEXT_DIGIT MOVF DATAVALUE,W ;GET DIGIT CALL GET_PATTERN ;DECODE MOVWF PORTD ;AND OUTPUT MOVF DIGIT,W ;GET DIGIT TO SWITCH ON MOVWF PORTA ;AND SWITCH ON CALL DELAY ;WAIT CLRF PORTA ;CLEAR DISPLAy INCF FSR ;POINT TO NEXT DIGIT RRF DIGIT ;MOvE ENABLE TO NEXT DIGIT DECF COUNT ;COUNT COUNT - 1 BTFSS STATUS,Z ;IF LAST START AGAIN GOTO NEXT_DIGIT ;ELSE Do NExT GOTO AGAIN ;AND REPEAT MOVF DIGIT,W ;GET NUMBER BETWEEN 0 - 9 ANDLW 0x0F ;ONLY 4 LSBs CALL GET_PATTERN ;DECODE MOVWF PORTD ;OUTPUT MOVLW 01 ;SELECT 1ST DIGIT MOVWF PORTA ;AND oUTPUT GOTO AGAIN ;REPEAT FOR EVER ; PORT INITIALISATION INIT BANK1 ;SET TO BANK 1 CLRF TRISD ;SET PORT D To oUTPUT MOVLW 06 ;MME PORT A DIGITAL MOVWF ADCON1 CLRF TRISA ;AND PORT OUTPUT BANK0 ;BAOK TO BANK 0 RETURN ;DECODE ROUTINE GET_PATTERN ADDWF PCL ;GOTO EQUIV PATTERN RETLW 0x3F ;ZERo PATTERN RETLW 0x06 ;oNE PATTERN RETLW 0x5B ;TWo PATTERN RETLW 0x4F ;THREE PATTERN RETLW 0x66 ;FOUR PATTERN RETLW 0x6D ;FIvE PATTERN RETLW 0x7D ;SIx PATTERN RETLW 0x07 ;SEvEN PATTERN RETLW 0x7F ;EIGHT PATTERN RETLW 0x67 ;NINE PATTERN RETLW 0x40 ;INVALID DIGIT RETLW 0x40 ;INvALID DIGIT RETLW 0x40 ;PINvALID DIGIT RETLW 0x40 ;INVALID DI3ITN RETLW 0x40 ;INVALID DIGIT RETLW 0x40 ;INvALID DIGIT ; SE TEST DATA SET_DATA MOVLW 0 ;-ZERoI MOVWF DIGIT1 ;AND STORE MOVLW 1 ;1 MOVWF DIGIT2 ;AND SToRE MOVLW 2 ;2 MOVWF DIGIT3 ;AND SToRE MOVLW 3 ;3 MOVWF DIGIT4 ;AND SToRE RETURN ; DELAY ROUTIN DELAY MOVWF TEMP ; SAVE MOVLW 0xFF; SET DELAY TIME MOVWF DELAY_TIME WAIT INCFSZ DELAY_TIME ; COUNT DOWN GOTO WAIT MOVF TEMP,W ; RESTORE W RETURN END