list        p=16F628A
    #include    <p16f628a.inc>
    __CONFIG    _CP_OFF & _WDT_OFF & _INTRC_OSC_NOCLKOUT


#define ALLOW   PORTA,3

    ORG H'0000'
    goto    start




;  Start
;----------------------------------------
start   ;MOVLW  0X07        ;Turn comparators off and
;   MOVWF   CMCON       ;enable pins for I/O


    bsf STATUS,RP0  ;Банка 1
    movlw   B'11010000'
    movwf   OPTION_REG
    bcf STATUS,RP0  ;Банка 0
    clrf    PORTA
    clrf    PORTB
    bsf STATUS,RP0  ;Банка 1
    clrf    TRISA
    clrf    TRISB
    bcf STATUS,5    ;Банка 0

    bcf INTCON,GIE

    goto    main


;   Main
; ----------------------------------

main    ;btfsc  INTCON,RBIF
;   call    isr

    bsf PORTA,0
    bsf PORTA,1
    bcf PORTA,2

    bsf PORTB,0
    bsf PORTB,1
    bcf PORTA,2

    bsf PORTA,3


loop    nop
    goto    main


    END