ma ajuta cineva cu o idee de citire senzor digital ? p16f876

[Vizitator danielmx]

vreau sa citesc acest sensorhttp://www.pololu.com/catalog/product/961 pe portulB la pic16f876a... cand este pozitionat deasupra unei linii negre ar trebui sa am "1" pe pinul respectiv iar cand am alb...ar trebui "0". Problema mea este ca nu reusesc sa citesc acest sensor "digital .."

asta este codul meu de citire in care am urmat pasii din datasheet:

[list=]The typical sequence for reading a sensor is:

 

1.Turn on IR LEDs (optional)

2.Set the I/O line to an output and drive it high

3.Allow at least 10 us for the 10 nF capacitor to charge

4.Make the I/O line an input (high impedance)

5.Measure the time for the capacitor to discharge by waiting for the I/O line to go low

6.Turn off IR LEDs (optional)

These steps can typically be executed in parallel on multiple I/O lines.

 

 

 

 

>citsenz:        bsf STATUS,RP0  movlw b'00000000'   movwf TRISB         ; 1) setare portb iesire   bcf STATUS,RP0   movlw b'11111111'                             ;    drive it high pt incarcarea condens  movwf PORTB    call delay10us                               ;asteapta ~10us sa se incarce cond   bsf STATUS,RP0  movlw b'11111111'                  ;portb = intrare  movwf TRISB      bcf STATUS,RP0  call delay1ms  call delay1ms    movf PORTB,0                                   ;citire senzor paralel cu pastrarea rezultatului in "citiresenzor"  movwf citiresenzor