;******************************************************
;*               ADC_PL.ASM
;* PORTA RA0接腳類比輸入，經ADC轉換後，PORTC輸出
;******************************************************
			list p=16F877		
#include 		<p16f877.inc>
;
VAL_US		equ	.5			; 25us delay 給定初值
count		equ	0x20		; 25us delay 變數位址
;
;******  程式開始 *********************
			org 	0x00			; reset vector
			nop					; Reserve for MPLAB-ICD
initial:	
			banksel	TRISC		; Select to bank1
			clrf	 	TRISC		; PORTC = Output
		banksel 	PORTC 		; Select to bank0
			clrf		PORTC		; Clear PORTC
			banksel	ADCON1	; Step1 Start
			clrf		ADCON1
			banksel	ADCON0	; 
			movlw	0x41
			movwf	ADCON0	; Step1 End

start:
			call		delay_25us	; Step3
			bsf		ADCON0,GO	; Step4
f0			
			btfsc		ADCON0,GO	; Step5
			goto		f0
			movf	ADRESH,W	; Step6
			movwf	PORTC
			goto		start			; Step7
;-------delay subroutine-----------
delay_25us:
			movlw	VAL_US
			movwf	count
dec_loop		nop
			decfsz	count,f
			goto		dec_loop
			return

			end