Programming NIOSII interfaced with custom component, using Avalon MM Interface

Hi,

I succeeded in implementing the system on board. My custom component is a 128 tap FIR filter which is to be started by NIOS and stimuli is also provided by nios. I made the custom component in Qsys and implemented the system.

Now i am able to write the c code successfully on the NIOS without any tool errors.

But, i am not able to communicate properly. Below is my code:

int var =1234;

IOWR(20496,0,11);

printf("%d\n",var); //prints 1234

var = IORD(20496,0);

printf("%d\n",var); // prints 0

When I am reading the same address and offset, it gives 0.