LED.asm

;   LED.asm
;   Lights up an LED.
;

        STATUS      EQU     0X03    ; Status Register
        PORTA       EQU     0X05
        PORTB       EQU     0X06
        TRISA       EQU     0X85
        TRISB       EQU     0X86

;=============== STATUS BITS =====================
        C           EQU     0X0     ; Carry Flag
        DC          EQU     0X01    ; Digit Carry Flag
        Z           EQU     0X02    ; Zero Flag
        PD          EQU     0X03    ; Power Down Bit
        TO          EQU     0X04    ; WDT Timeout Bit
        RP0         EQU     0X05    ; Bank Select
        RP1         EQU     0X06    ; Bank Select (unused)
        IRP         EQU     0X07    ; Unused
;=================================================
        DLY_CNT1    EQU     0X20
        DLY_CNT2    EQU     0X21
        __CONFIG    0X3FF2
                    ORG     0X00    ; Processor reset vector
                    GOTO    START
                    ORG     0X04
                    RETFIE
START
                    BSF     STATUS, RP0 ; Select Bank 1
                    BCF     STATUS, RP1 ;
                    CLRF    TRISB       ; PORTB is output only
                    BCF     STATUS, RP0 ; Select Bank 0
                    CLRF    PORTB       ;
                    CLRF    DLY_CNT1
                    CLRF    DLY_CNT2
L1                  INCF    PORTB       ;
L2                  DECFSZ  DLY_CNT2
                    GOTO    $-1
                    DECFSZ  DLY_CNT1
                    GOTO    L2
                    GOTO    L1          ;
                    END