External peripherals interface

Hi guys.

I'm a beginner using Nios II software and i need some advices for controlling an external camera connected to PROTO1 block in an Altera development board mounting EP2C35 FPGA.

On SOPC i added a couple of PIO(??) for Ctrl bits and Data bits of the Camera,ABLE to Call IRQs. System Generation is ok,compilation is ok, software is ok , BUT:

1)If i try to read the pio ports,these are always 0 (it seems no datas eventhough the oscilloscope show datas present);

1) program stops when reach alt_irq_register(a,b,c) instruction;

Have i to add an avalon tristate bridge for allowing pios's interface or it's enough to add pios on SOPC and use pin planner? Am i wrong?What have i to add?

I've done the second but happen 1) and 2)

Thank you very much

Paolo http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/unsure.gif