ex923

;##############################################
;Title  : ex923 ADC
;Description : CDS 高於 N LED亮
;Date   : 2021 / 01 / 04
;##############################################
list p=16F877A
#include <p16f877A.inc> ; Include file locate at defult directory
; CONFIG
; __config 0xFF7A
 __CONFIG _FOSC_XT & _WDTE_OFF & _PWRTE_OFF & _BOREN_ON & _LVP_OFF & _CPD_OFF & _WRT_OFF & _CP_OFF


addr_delay equ 0x20

org 0x0
Setup:
    banksel TRISA

    clrf ADCON1 ;向左靠
    clrf TRISD

    banksel PORTA
    movlw b'11000001'
    movwf ADCON0

ADCONVERT:
    call delay
    bsf ADCON0,GO
ADWAIT:
    nop
    btfss PIR1,ADIF
        goto ADWAIT
    bcf PIR1,ADIF

    movlw .100
    subwf ADRESH,w
    btfss STATUS,C
        goto DARK

    clrf PORTD
    goto ADCONVERT


DARK:
    movlw 0xFF
    movwf PORTD
    goto ADCONVERT

delay:
    movlw .24
    movwf addr_delay

    delay_loop:
        decfsz addr_delay,f
            goto delay_loop
        return
end