#include <p16f887.inc>
;    __CONFIG 0x3f21
    __CONFIG _CONFIG1,_LVP_OFF &_FCMEN_OFF &_IESO_OFF & _BOR_OFF & _CPD_OFF & _CP_OFF & _MCLRE_OFF & _PWRTE_ON & _WDT_OFF &_INTRC_OSC_NOCLKOUT
    __CONFIG _CONFIG2, _WRT_OFF &_BOR21V
    
    ;setup variables
    
    cblock
	w2
    endc
    
    org 0
    
    
    
initRegs:
    ;Setup PORTD
    banksel TRISD
    clrf TRISD	;set PORTD as direction as output
    banksel PORTD
    clrf PORTD	;Clear output pins at startup
    ;Setup our AI on pin RA0 
    banksel TRISA
    movlw 0xff
    movwf TRISA ;set RA0 as input, the rest are outputs
    
    banksel ANSEL
    movlw 0x01
    movwf ANSEL	;Set RA0 as an analog input
    banksel ADCON1 
    ;movlw 0b11110000;
    movlw 0b11110000;
    movwf ADCON1 ;b[7] sets right justification, b[6:4] sets CS = FRC,
    ;b[2]+b[1:0] sets Vss and Vdd as refrences 
    
    banksel ADCON0
    movlw 0b01000001
    movwf ADCON0    ; b[7:6] Configure A2D for Fosc/8, b[5:3] Select Channel RA0
    ;b[0] Enable A2D Converter module
    
;    ;Test outputs (debug only)
;    banksel PORTD
;    movlw 0xff
;    movwf PORTD
;    goto $
    
  
main

    ; TODO Step #5 - Insert Your Program Here

    
    goto acquireAI                          ; loop forever
    goto main
    nop
    nop
    nop

    
    
acquireAI
    banksel ADCON0
    nop ; 5uS needed to charge capacitor in RC circuit
    nop
    nop
    nop
    nop
    
    bsf ADCON0, GO_DONE ; Set A2D conversion status to in progress
    btfsc ADCON0, GO_DONE ; If in progress Keep Waiting Until Finsished (GO_DONE == 0)
    goto $-1
    banksel ADRESH
    movfw ADRESH    ;copy lower 8 bits ADC result held in ADRESL 
    ;(because we chose right justification) to working register
    banksel PORTD
    ;movlw 0xff
    movwf PORTD	;set PORTD to ADC result
    
  
return
    

    END