list p=16F84A

 #include 

 __config _CP_OFF & _WDT_OFF & _PWRTE_ON & _XT_OSC



bitSDI	equ	3

bitCLK	equ	2

bitLAT	equ	1

iniTMR	equ	d'022'



count1	equ	0x0C

dig_U	equ	0x0D

dig_D	equ	0x0E

dig_H	equ	0x0F

impnum	equ	0x10

segcod	equ	0x11

hdnull	equ	0x12



		org	0x000

		clrf	PORTA

		clrf	PORTB

		clrf	INTCON

		clrf	TMR0

		clrWDT



		bsf	STATUS,RP0

		movlw	b'11111111'

		movwf	PORTA

		movlw	b'00000001'

		movwf	PORTB

		movlw   b'01000111'

		movwf	OPTION_REG

		bcf	STATUS,RP0



loop		clrf	impnum

		movlw	d'010'

		movwf	dig_U

		movwf	dig_D

		movwf	dig_H

		

		movwf	count1

		bcf	INTCON,INTF

ms600

		movlw	iniTMR

		movwf	TMR0

		bcf	INTCON,T0IF

ms60					

		btfss	INTCON,INTF

		goto	NoINCR

DoINCR

		incf	impnum,f

		decfsz	dig_U,f

		goto	eoINCR

		movlw	d'010'		

		movwf	dig_U

		decfsz	dig_D,f

		goto	eoINCR

		movlw	d'010'

		movwf	dig_D

		decfsz	dig_H,f

		goto	eoINCR

		movlw	d'010'

		movwf	dig_H

eoINCR

		bcf	INTCON,INTF

NoINCR

        	btfss	INTCON,T0IF

		goto	ms60

		decfsz	count1,f

		goto	ms600



		clrf	hdnull

		movf	dig_H,W

		call	SendDD		

		movf	dig_D,W

		call	SendDD		

		bsf	hdnull,0

		movf	dig_U,W

		call	SendDD



		bsf	PORTB,bitLAT

		nop

		bcf	PORTB,bitLAT

		nop

		goto	loop



SendDD		sublw	d'010'

		btfss	STATUS,Z

		goto	DoDIGIT

		btfss	hdnull,0

		goto	DoBLANK

DoDIGIT

		bsf	hdnull,0

		call	SEG_7

DoBLANK

		movwf	segcod



		movlw	7

		movwf	count1

BitLoop

		rlf	segcod,f

		btfss	STATUS,C

		goto	SendB0

		goto	SendB1

SendB0	bcf		PORTB,bitSDI

		goto	BitReady

SendB1	bsf		PORTB,bitSDI

		nop

BitReady

		bsf	PORTB,bitCLK

		nop

		bcf	PORTB,bitCLK

		nop

		decfsz	count1,f

		goto	BitLoop

		return

		

SEG_7	andlw	0x0F

		addwf	PCL,f	

		retlw	b'01111110'

		retlw	b'00000110'

		retlw	b'11011010'

		retlw	b'11001110'

		retlw	b'10100110'

		retlw	b'11101100'

		retlw	b'11111100'

		retlw	b'01000110'

		retlw	b'11111110'

		retlw	b'11101110'

		retlw	b'10000000'

		retlw	b'01000000'

		retlw	b'00100000'

		retlw	b'00010000'

		retlw	b'00001000'

		retlw	b'00000100'

	end