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Altera_Forum's avatar
Altera_Forum
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9 years ago

SDRAM read out of sync

I am testing SDRAM read and write using nios. I wrote a simple function with loops to write to 15 memory locations and read them back. for(i=min; i<max; i++) { IOWR(SDRAM_BASE,0,i...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
9 years ago

Thanks for your reply.

The IORD was actually a typo. Now I got an example circuit and made the read/write working. But I find it interesting that when I write and read in the same loop(the following code) I can read perfectly.

for(i=min; i<max; i++)

{

IOWR_32DIRECT(pbase,0,i);

printf("%d %d \n",i, iord_32direct(pbase,0));

}

However, when I write in a loop and read in another loop I got some memory locations read wrong. Is there any explanation for this?

for(i=min; i<max; i++)

{

IOWR_32DIRECT(pbase[i],0,i);

}

printf("Reading from Mem \n");

for(j=min; j<max; j++)

{

printf("%d %d \n",j, IOWR_32DIRECT(pbase[j],0));

}

Cheers,