My First line follower code help??

dons21 · Jun 13, 2010

Hi all, I built a basic line follower, It has 4 ir sensors controlled with lm324 op-amp and uses SN754410 motor driver.

I can adjust the sensors with a pot which gives me a HIGH output when the line is detected.

I tested the line follower by connecting two of the sensors (output from op-amp) directly to the motor driver and it worked. The robot followed the line quite well once the sensors had been adjusted.

Now I built this to learn more about pic programming so I connected the sensors and motor driver to 12f629.

I all I wanted was the processor to turn on the motors when a line had been detected so I wrote the following code. but it doesn't work well I am not sure if the motors are causing the pic problems or its my code.

Please could someone have a look, I will post a schematic later

Thanks Don

;******************************************************************************
; *
; Filename: first_line_follower.asm *
; Date: 13-6-10 *
; File Version: 0.1v *
; *
; Author: don *
; Company: *
; *
; *
;******************************************************************************
; *
; Files required: P12F629.INC *
;******************************************************************************
;
; Vdd IIIII Vss
;Left Sensor GP5 I I GP0
;Right Sensor GP4 I I GP1 Left Motor
; GP3 IIIII GP2 Right Motor
;
;******************************************************************************

;------------------------------------------------------------------------------
; PROCESSOR DECLARATION
;------------------------------------------------------------------------------

LIST P=12F629 ; list directive to define processor
#INCLUDE <P12F629.INC> ; processor specific variable definitions

;------------------------------------------------------------------------------
;
; CONFIGURATION WORD SETUP
;
; The 'CONFIG' directive is used to embed the configuration word within the
; .asm file. The lables following the directive are located in the respective
; .inc file. See the data sheet for additional information on configuration
; word settings.
;
;------------------------------------------------------------------------------

__CONFIG _CP_OFF & _CPD_OFF & _BODEN_OFF & _MCLRE_ON & _WDT_OFF & _PWRTE_ON & _INTRC_OSC_NOCLKOUT

;------------------------------------------------------------------------------
; OSCCAL RESTORE (not required if internal OSC is not used)
;------------------------------------------------------------------------------
RESET_VECTOR CODE 0x0000 ; processor reset vector

errorlevel -302
BSF STATUS,RP0 ; set file register bank to 1
CALL 0x3FF ; retrieve factory calibration value
MOVWF OSCCAL ; update register with factory cal value
BCF STATUS,RP0 ; set file register bank to 0

; set up inputs and outputs

;****** Turn Off Comparator
movlw b'00000111' ; Turn off Comparator 0x07
movwf CMCON ; Turn off Comparator 0x07

BSF STATUS,RP0 ; SELECT BANK 1
MOVLW B'111001' ;GP5,GP4,GP3,GP0 INPUTS GP1,GP2 OUPUTS
MOVWF TRISIO
BCF STATUS,RP0 ;BANK0

clrf GPIO ; Clear GPIO

start
BTFSS GPIO,5 ; Test Left Sensor (skip if high)
BCF GPIO,2 ; Turn off Right Motor
BTFSC GPIO,5 ; Test Left Sensor (skip if low)
BSF GPIO,2 ; Turn on right motor
BTFSS GPIO,4 ; Test right sensor (skip if high)
BCF GPIO,1 ; Turn off left motor
BTFSC GPIO,4 ; Test right sensor (skip if low)
BSF GPIO,1 ; Turn on left motor

GOTO start

END ; directive 'end of program'

aljamri · Jun 13, 2010

You are running the program with the PIC full speed, you may need to have a time delay among your code.

EDIT: Sorry, I'm stuck, This is true if you are using Stepper motor.

Check your config. word for MCLRE and PWRTE, I think they have to be OFF.

Pommie · Jun 14, 2010

I can't see anything wrong with your code but I would remove the call to 0x3ff and the subsequent store to OSCCAL as sometimes the retlw at that address gets written over and this results in a continuous loop.

BTW, when posting code place

Code:

 before it and

after it so that it keeps it's formating like this,

Code:

		__config _CP_OFF & _CPD_OFF & _BODEN_OFF & _MCLRE_ON & _WDT_OFF & _PWRTE_ON & _INTRC_OSC_NOCLKOUT 

;------------------------------------------------------------------------------  
; OSCCAL RESTORE (not required if internal OSC is not used)  
;------------------------------------------------------------------------------  
RESET_VECTOR	code	0x0000		; processor reset vector

		errorlevel -302
		bsf	STATUS,RP0	; set file register bank to 1 
	;	call	0x3FF		; retrieve factory calibration value
	;	movwf	OSCCAL		; update register with factory cal value 
		bcf	STATUS,RP0	; set file register bank to 0

; set up inputs and outputs  
;****** Turn Off Comparator  
		movlw	b'00000111'	; Turn off Comparator 0x07 
		movwf	CMCON		; Turn off Comparator 0x07


		bsf	STATUS,RP0	; SELECT BANK 1
		movlw	B'111001'	;GP5,GP4,GP3,GP0 INPUTS GP1,GP2 OUPUTS
		movwf	TRISIO
		bcf	STATUS,RP0	;BANK0

		clrf	GPIO		; Clear GPIO 
start			 
		btfss	GPIO,5		; Test Left Sensor (skip if high)
		bcf	GPIO,2		; Turn off Right Motor
		btfsc	GPIO,5		; Test Left Sensor (skip if low)
		bsf	GPIO,2		; Turn on right motor 
		btfss	GPIO,4		; Test right sensor (skip if high)
		bcf	GPIO,1		; Turn off left motor
		btfsc	GPIO,4		; Test right sensor (skip if low)
		bsf	GPIO,1		; Turn on left motor

		goto	start

Mike.

dons21 · Jun 14, 2010

Well Thanks for the replies, is there anything wrong with my schematic, like I said before. The line follower works when I connect the op-amp to the motor controller, but when connected to the pic i think the motors cause the pic problems. Anyway here is my schematic.
Schematic

Transistorman · Jun 15, 2010

Re

Where is the output go
**broken link removed**

dons21 · Jun 15, 2010

Hi, they go nowhere at the moment. I have 4 sensors to detect the line, and at the moment I am only using the two center sensors. Once I have mastered playing/programing the 12f629 I will use a 16F628 chip and connect the extra sensors to the 16F chip.

dons21 · Jun 20, 2010

Well, I fixed the problem, I needed to have resistor on the MCLR pin. When the motors were running it was resetting the pic.

Now to my next problem, I have added a push button to start and stop the code but the button is very sporadic. Here is my code;

Code:

;******************************************************************************
;                                                                             *
;    Filename:      first_line_follower.asm                                   *
;    Date:          13-6-10                                                   *
;    File Version:    0.1v                                                    *
;                                                                             *
;    Author:          don                                                     *
;    Company:                                                                 *
;                                                                             *
;                                                                             *
;******************************************************************************
;                                                                             
;    Files required: P12F629.INC                                              
;******************************************************************************
;                
;		        Vdd IIIII Vss
;	Left motor	GP5 I   I GP0 Start Stop
;  Right motor	GP4 I   I GP1 Left  sensor
;    			GP3 IIIII GP2 Right sensor                               
;                                                                             
;******************************************************************************

;------------------------------------------------------------------------------
; PROCESSOR DECLARATION
;------------------------------------------------------------------------------

     LIST      P=12F629              ; list directive to define processor
     #INCLUDE <P12F629.INC>          ; processor specific variable definitions

;------------------------------------------------------------------------------
;
; CONFIGURATION WORD SETUP
;
; The 'CONFIG' directive is used to embed the configuration word within the 
; .asm file. The lables following the directive are located in the respective 
; .inc file.  See the data sheet for additional information on configuration 
; word settings.
;
;------------------------------------------------------------------------------

    __CONFIG   _CP_OFF & _CPD_OFF & _BODEN_OFF & _MCLRE_ON & _WDT_OFF & _PWRTE_ON & _INTRC_OSC_NOCLKOUT 


;------------------------------------------------------------------------------
; OSCCAL RESTORE (not required if internal OSC is not used)
;------------------------------------------------------------------------------

RESET_VECTOR  CODE      0x0000 			; processor reset vector
       
		 errorlevel -302
        BSF     STATUS,RP0    			; set file register bank to 1 
        CALL    0x3FF         			; retrieve factory calibration value
       	MOVWF   OSCCAL        			; update register with factory cal value 
       	BCF     STATUS,RP0   			; set file register bank to 0
        
    
; set up inputs and outputs


;****** Turn Off Comparator
		movlw	b'00000111'		; Turn off Comparator 0x07 
		movwf	CMCON			; Turn off Comparator 0x07


		BSF		STATUS,RP0				; SELECT BANK 1
		MOVLW	B'001111'				        ;GP3,GP2,GP1,GP0 INPUTS GP4,GP5 OUPUTS
		MOVWF	TRISIO
	
		BCF		STATUS,RP0				;BANK0

		clrf	GPIO					                ; Clear GPIO 

		nop
		nop

on		BTFSC	GPIO,0					; Test start/stop (skip if low)		
		GOTO	on						; loop till button press		

loop	
		BTFSS	GPIO,1					; Test Left Sensor (skip if high)
		BCF		GPIO,4					; Turn off Right Motor
		BTFSC	GPIO,1					; Test Left Sensor (skip if low)
		BSF		GPIO,4					; Turn on right motor	
		BTFSS	GPIO,2					; Test right sensor (skip if high)
		BCF		GPIO,5					; Turn off left motor
		BTFSC	GPIO,2					; Test right sensor (skip if low)
		BSF		GPIO,5					; Turn on left motor
		
		
		BTFSS	GPIO,0					; Test start/stop (skip if high)
		GOTO	off
		GOTO 	loop	

off		
		clrf	GPIO
		GOTO	on



        END                     		  ; directive 'end of program'

Any ideas are welcome.

Thanks

Mosaic · Jun 20, 2010

Have a look at the switch debounce code discussion near the end of this thread.
https://www.electro-tech-online.com/threads/dissassembled-trisc-inst-question.108514/

My First line follower code help??

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