Mpasm cho nguoi moi bat dau

[navy]

A falleaf hoac cac cao thu ve PIC thanh lap dien dan nay thuc su la mot dien dan co ich cho nhung nguoi yeu thich lap trinh VDK. Cam on cac ban rat nhieu, da tu lau minh am tham hoc mot minh theo cac ban va cung lam duoc mot so viec nho khi su dung PIC. Minh la nguoi moi hoc PIC va dang dung PIC de lap trinh cho robot tu dong . Nhung trong qua trinh vua lam vua hoc den gio moi tich luy duoc chut "von lieng " de co the tham gia cung dien dan voi muc dich hoc hoi anh em.
Minh dang lap trinh voi 16F877A, ban dau robot cua minh chay bam duong thi rat tot va on dinh, tuy nhien nhung doan dem vach cua minh no van chua nhan duoc, co luc thi chi 1 vach dau no da cua roi. Mong anh em tren dien dan kiem tra giup.
Phan cung cua minh su dung 6 led thu noi toi cong portA, (nam tren vach trang ='1')
RB0 - noi dong co phai
RB1 - dao chieu dong co phai
RB2 - dong co trai
RB3 - dao chieu dong co trai
Bam duong su dung hai bit RA2,RA3 nam tren vach trang.
Dem vach su dung hai bit RA0 va RA5
Do dong co cua minh toc do thap nen ko can dieu xung van bam duong tot
So vach can dem =4;
Day la chuong trinh cua minh:

///////////////////////////////////////////////////////////////////////////////////////
 TITLE "test bam duong cua phai01.asm"
   processor 16f877a          ;identify processor 16F877A
   include <p16f877a.inc>     ;header file
   ;thuc hien: navy
   ;configuration  Intialize 
   
   __CONFIG _CP_OFF&_WDT_OFF&_BODEN_OFF&_PWRTE_ON&_XT_OSC&_WRT_OFF&_LVP_OFF&_CPD_OFF&_DEBUG_OFF
   
  
	count1			equ	0x20
	count2			equ	0x21
	count3			equ	0x22
	vach_ngang_1		equ	0x23

	;here start program

             org 0x0000
	goto start

start
	movlw	d'4'			;vach_ngang_1 = 4
	movwf	vach_ngang_1
	bcf  	STATUS,RP1
    	bsf  	STATUS,RP0 		; select Bank1
    	clrf 	TRISB     	 	; initialize portB = output
    	bcf  	STATUS,RP0		; select Bank0
	movlw	b'00000101'
	movwf	PORTB 	  ; set PORTB<2,0> bits drive robot forward
	clrf	PORTA			; clear latch PORTA
	bsf	STATUS,RP0	 	; select Bank1
	movlw	b'00000110'
	movwf	ADCON1			; disable A/D converter
	movlw	b'00111111'		; initialize portA is input_pin
	movwf	TRISA
	call	di_thang_1
	call	cua_phai_1

di_thang_1
	bcf  	STATUS,RP1
	bcf  	STATUS,RP0	 	; select Bank0 
	btfss	PORTA,2
	call	lech_trai_1	
	btfss	PORTA,3
	call	lech_phai_1
	btfss	PORTA,0
	goto	thoat		 	;
	btfss	PORTA,5
	goto	thoat
	decfsz	vach_ngang_1,1	 ;default result in vach_ngang_1
	goto	thoat
	goto	di_thang_1
thoat
	return
	
lech_trai_1
	bcf  	STATUS,RP1		;select Bank0
	bcf  	STATUS,RP0
	bcf	PORTB,0
	call	delay_10ms
	btfss	PORTA,2		 	;Test bit sensor 02
	goto	lech_trai_1
	return
lech_phai_1
	bcf  	STATUS,RP1
	bcf  	STATUS,RP0		; select Bank0
	bcf	PORTB,2
	call	delay_10ms		
	btfss	PORTA,3		 	;Test bit sensor 03
	goto	lech_phai_1
	return	
cua_phai_1
	bcf  	STATUS,RP1
	bcf  	STATUS,RP0
	bsf	PORTB,1
	btfss	PORTA,0
	goto	cua_phai_1
	call	delay_phai1
	return
	
delay_10ms
	movlw	d'10'
	movwf	count1
d1
	movlw	d'199'
	movlw	count2
	movlw	d'1'
	movwf	count3
delay_0
	decfsz	count2,1
	goto	$+2
	decfsz	count3,1
goto	delay_0
	decfsz	count1,1
	goto	d1
	return
delay_phai1
	movlw	d'50'
	movwf	count1
d1
	movlw	d'199'
	movlw	count2
	movlw	d'1'
	movwf	count3
delay_0
	decfsz	count2,1
	goto	$+2
	decfsz	count3,1
	goto	delay_0
	decfsz	count1,1
	btfsc	PORTA,0
	goto	delay_phai1
	btfss	PORTA,2
	goto	delay_phai1
	goto	$+2
	goto	d1
	return
	
end

Bay gio minh muon su dung TIMER0 de dem vach nhung khoi tao va chuong trinh ngat phai viet nhu the nao ? Cac ban co the giup minh viet mot doan su dung Timer0 de dem vach duoc ko( Dem trong luc van chay thang)? Mong !