Hi everyone ,
This thing has got me stuck for like 3 days now:

I'm connecting 8 IR reciever diodes to my micro using a 3 bit multiplexer .. and I got it so that when an addressed IR diode is detecting any light, the output goes to zero, and when it doesn't the output goes high. Also, I have a diode at the output so that the high state is clamped , so when it detects IR, it grounds the pin ... but somehow when I set the pin to 1 to use it as an input, It doesnt detect that the pin is grounded ... I've checked it and the grounding is even enough to light up an LED ... oh by the way I'm using port 0 with 1k external pullup resistors .. can you help me please?

heres the dialog for the output of my IR thing...




I have tested the circuit manually and it works perfectly (I enable the output by raising the EN line and then the output is low if I emit IR light on the diodes ...) but somehow the pin seems not to detect it .. I dunno ... can someone help please?

I really need to do this .

Thank you.