printf() after IORD always -1

Hi,

I wrote a very simple Verilog module. This module is an Avalon slave on Nios II. It has 2 registers that can be read and write. I implemented it on a SoPC with where I created:

-the Nios II

-the jtag

-the SDRAM

-my Verilog module.

I instantied this SoPC on a Top level module also with a PLL to give the right clock to SDRAM. I'm using a DE0 Nano board.

Then I wrote also a simple C program:

#include "system.h"# include "stdio.h"# include "io.h"
# define REG_BASE             (*(volatile unsigned int*) REGISTRI_0_BASE)
int main(){
    long int a,b;
    a=IORD(REG_BASE, 0);
    printf("%ld",a);
    IOWR(REG_BASE, 0, 12);
    IOWR(REG_BASE, 1, 1);
    a=IORD(REG_BASE, 0);
    printf("%ld",a);
    b=IORD(REG_BASE, 1);
    printf("%ld",b);
while(1){
};
}

This program give this output:

-1 -1 -1

But i expected

0 12 1

Do you know why? Do you need my verilog code?

Thank you