"Olin Lathrop" <olin_piclist@embedinc.com> writes:

> Paul Chany wrote:
>> The circuit can be seen here:
>> http://csanyi-pal.info/album/index.php/album/section/2#1
>
> Not really.  Details too small.

Then You can see it with original size here:
http://csanyi-pal.info/album/index.php/image/view/4

The changed assembly program is bellow.
--------->
    LIST P=16F877A
    #INCLUDE "P16F877A.INC"
    __CONFIG _XT_OSC&_CP_OFF&_WDT_OFF&_LVP_OFF

    ORG     0

START
                        ;switching to BANK1: 00
    BCF     STATUS,RP1  ;Bit Clear file, RP1=0
    BSF     STATUS,RP0  ;Bit Set file, RP0=1
    MOVLW   0x06        ;6 to Work register
    MOVWF   ADCON1      ;PORTA digital
    MOVLW   B'00011111'
    MOVWF   TRISA       ;PORTA as input
    MOVLW   B'00000000'
    MOVWF   TRISD       ;PORTD as output

    BCF     STATUS,RP0  ;switching to BANK0: 00

    MOVLW   B'00000000' ;switch off the LEDs
    MOVWF   PORTD

MAIN
    BTFSC   PORTA,2     ;skip the next command if the
                        ;Optical Slotted Switch connected to RA2 pin
                        ;(PORTA) with Collector of the PhotoTransistor
                        ;give to us logical 0, because there isn't
                        ;anything in the slot
    BSF     PORTD,1     ;switch on the 1. LED of PORTD
    BSF     PORTD,0     ;switch on the 0. LED of PORTD
    GOTO    MAIN

END
---------<

>> I can't se any changes on LED's here when I put a paper in the slot
>> of the optical swith.
>
> Paper is not likely opaque enough.  Try aluminum foil.

I try with cardboard (pasteboard). No changes seen.
Actually, I can see the 0. (PORTD,0) and 1. (PORTD,1) LED's to light
permanently.

--
Regards, Paul Chany
http://csanyi-pal.info

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