[PIC] Light follower robot

[rb13]

I designed a light follower robot using pic16f877a using assembly language.
However, when the switch is on the robot goes forward immediately also when I am not moving the robot it keeps going forward. I need it to stay in place.
The code is:

#INCLUDE <P16F877A.INC> 

	__CONFIG _XT_OSC & _WDT_OFF & _PWRTE_OFF & _BODEN_OFF & _LVP_OFF & _CPD_OFF & _WRT_OFF & _CP_OFF

#DEFINE	IN1_L 	PORTB, 0
#DEFINE	IN2_L	        PORTB, 1
#DEFINE	IN3_R	PORTB, 2
#DEFINE	IN4_R	PORTB, 3
#DEFINE	MID		0X021
#DEFINE	RIGHT	0X022
#DEFINE	LEFT	0X023

	CBLOCK	0x20
	A1,COUNTER
	ENDC
		
	ORG		0X000
	GOTO	MAIN

	ORG		0X004 	
	BCF		INTCON,T0IF
	MOVLW	-D'125'
	MOVWF	TMR0
	DECFSZ	COUNTER,F
	RETFIE
	MOVLW	D'125'
	MOVWF	COUNTER
	CALL	TEST
	RETFIE

MAIN
	CALL	SETUP
	MOVLW	D'125'
	MOVWF	COUNTER
	MOVLW	-D'125'
	MOVWF	TMR0	
	BSF		INTCON,	T0IE
	BSF		INTCON,	GIE
	GOTO	$
					
A2D_CHANEL_0
	MOVLW	B'01000001'		
	MOVWF	ADCON0	
	CALL	A2D_DELAY
	BSF     ADCON0,GO       
	BTFSC   ADCON0,GO       
        GOTO    $-1
	MOVF    ADRESH,W
	MOVWF	MID	
        RETURN

A2D_CHANEL_1
	MOVLW	B'01001001'		
	MOVWF	ADCON0	
	CALL	A2D_DELAY
	BSF     ADCON0,GO       
	BTFSC   ADCON0,GO       
        GOTO    $-1
	MOVF    ADRESH,W
	MOVWF	LEFT		
        RETURN

A2D_CHANEL_3
	MOVLW	B'01011001'		
	MOVWF	ADCON0	
	CALL	A2D_DELAY
	BSF     ADCON0,GO       
	BTFSC   ADCON0,GO       
        GOTO    $-1
	MOVF    ADRESH,W
	MOVWF	RIGHT	
        RETURN

TEST
	CALL A2D_CHANEL_0
	CALL A2D_CHANEL_1
	CALL A2D_CHANEL_3
	MOVF	MID,W
	SUBWF	RIGHT,1
	BTFSS	STATUS,C
	GOTO	MOTOR_RIGHT
	SUBWF	LEFT,1
	BTFSS	STATUS,C
	GOTO	MOTOR_LEFT
	GOTO	MOTOR_FORWARD
	RETURN

A2D_DELAY					
	MOVLW	D'5'
	MOVWF	A1
	DECFSZ	A1, F
	GOTO	$-1
	RETURN

MOTOR_L_CCW
	BSF		IN1_L
	BCF		IN2_L
	RETURN
	
MOTOR_L_CW
	BCF		IN1_L
	BSF		IN2_L
	RETURN
	
MOTOR_L_STOP
	BCF		IN1_L
	BCF		IN2_L
	RETURN

MOTOR_R_CCW
	BSF		IN3_R
	BCF		IN4_R
	RETURN
	
MOTOR_R_CW
	BCF		IN3_R
	BSF		IN4_R
	RETURN
	
MOTOR_R_STOP
	BCF		IN3_R
	BCF		IN4_R
	RETURN

MOTOR_FORWARD
	CALL MOTOR_L_CW
	CALL MOTOR_R_CW
	RETURN

MOTOR_RIGHT
	CALL MOTOR_R_STOP
	CALL MOTOR_L_CCW
	RETURN

MOTOR_LEFT
	CALL MOTOR_L_STOP
	CALL MOTOR_R_CCW
	RETURN

MOTOR_STOP
	CALL MOTOR_L_STOP
	CALL MOTOR_R_STOP
	RETURN

SETUP
	CLRF	PORTA
	CLRF	PORTB
	CLRF	PORTC
	CLRF	PORTD
	CLRF	PORTE
	BSF 	STATUS, RP0
	MOVLW	B'00000100'
	MOVWF	ADCON1
	MOVLW	B'00000111'
	MOVWF	CMCON
	MOVLW	B'00001011'
	MOVWF	TRISA
	MOVLW	B'00000000'
	MOVWF	TRISB
	MOVLW	B'00000000'
	MOVWF	TRISC
	MOVLW	B'00000000'
	MOVWF	TRISD
	MOVLW	B'00000000'
	MOVWF	TRISE
	MOVLW	B'11000011'
	MOVWF	OPTION_REG
	BCF 	STATUS, RP0
	RETURN
	 
	END

 

[udayan92]

when the switch is on the robot goes forward immediately also when I am not moving the robot it keeps going forward.

Could you explain it in more detail?

 

[rb13]

The robot has a switch to turn power on so immediately the robot moves forward. Also when i am not moving the light it keeps moving forward. I want it to stay in place