CONFIG
    BANKSEL ADCON1 ;
    MOVLW b'00000000' ;right justify
    MOVWF ADCON1 ;Vdd and Vss as Vref
    BANKSEL TRISA ;
    BANKSEL ADCON0 ;
    MOVLW b'10101001' ;ADC Frc clock,
    MOVWF ADCON0 ;AN0, On
    CALL tempo ;Acquisiton delay

MAINLOOP
    BSF ADCON0,GO ;Start conversion
    BTFSC ADCON0,GO ;Is conversion done?
    GOTO $-1 ;No, test again

    BANKSEL ADRESH ;

    MOVF ADRESH,W ;Read upper 2 bits
    MOVWF RESULTHI ;store in GPR space
    ;MOVWF PORTA
   ; movfw B'00100000'

    CLRF PORTA

    MOVFW B'10100000'
    SUBWF RESULTHI
    BTFSS STATUS,C
    CALL NB4

    MOVFW B'1000000'
    SUBWF RESULTHI
    BTFSS STATUS,C
    CALL NB3

    MOVFW B'01000000'
    SUBWF RESULTHI
    BTFSS STATUS,C
    CALL NB2

    MOVFW B'00100000'
    SUBWF RESULTHI
    BTFSS STATUS,C
    CALL NB1

    GOTO MAINLOOP