using 7 segment display in DE1 soc

I am trying to use the 7 segment display of board de1 soc.

I am using linux image in an SD memory card. I could compile successful the hello.c, that has this code:

int main(int argc, char** argv) {

printf("Hello SoC FPGA!\n");

return 0;

}

Running it I could verify that my installation, I am using cross compiling on Windows, is working fine.

After I tried an example to write in 7 segment display.

I tried this code:

# define ADDR_7SEG1 ((volatile long *) 0xFF200020)

int main()

{

*ADDR_7SEG1 = 0x00000006;

}

But when I run it on the board I receive a segmentation fault .... But I don't understand why this is happening.

Somebody has some tips in what is wrong? Is there something that needs to be configured before in Hardware or Software?