Simple Black Line Follower 2011-05-15

list p=16f628A
#include<p16f628.inc>
__CONFIG _MCLRE_ON & _CP_OFF & _WDT_OFF &
_INTRC_OSC_NOCLKOUT
ERRORLEVEL -302
cblock 0x20
temp
temp_s
endc
;******************************************************************
org 0x00
goto main
;***********************************INTERRUPT LOOP*****************
org 0X04
inter:
movwf temp
swapf STATUS,w
clrf STATUS
movwf temp_s
btfsc PORTB,0x00
goto loop1
loop2:
movlw b'00000101'
movwf PORTA
btfsc PORTB,0x05
goto loop2
goto loop_x
loop1:
movlw b'10001000'
movwf PORTA
btfsc PORTB,0x00
goto loop1
loop_x
bcf INTCON,0x01
bcf INTCON,0x00
swapf temp_s,w
movwf STATUS
swapf temp,w
retfie
main:
bsf INTCON,0x07 ;Globel interrupt enable(we are using
interr.)
bsf INTCON,0x04
bsf INTCON,0x03 ;RB4-RB7 interrupt on change is
enabled/ in other words these pins will also
work as
;interrupts and interrupt will occur every
time any of these pin changes state
; i.e.:HIGH to LOW or LOW to HIGH, we
can not set it to be on eather one state
change
bcf INTCON, 0x01
bcf INTCON, 0x00 ;Clear RB4-RB7 interrupt flag so,
that another interr. can occur.
;**********************************SET UP THE PORTS *****************
bsf STATUS,RP0 ;switch to BANK 1
movlw b'00100001'
movwf TRISB ;set RB6 & RB5 as input
movlw b'00000000'
movwf TRISA ;setPORT A all output
bcf STATUS,RP0 ;back to BANK 0
movlw 0x07 ;turn comparators off, so HIGH will be
simple HIGH rather than +5V (compared to
supply) so with the LOW
movwf CMCON
Loop:
movlw b'00001001'
movwf PORTA ;set pin 0 of port a HIGH
goto Loop
END