Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
17 years ago

DDR2 reading errors on last two words

Hi, I've some problems with my ddr2 design. I use Altera DDR2 high performance IP on pci express dev board (Stratix II GX). I build some logic around my memory controler in order to test...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
17 years ago

pnf_per_byte is indicating the momentary check result, pnf_persist should go high at begin of each test pass and optionally low, when a verify error occurs. Cause pnf_per_byte is high during (at least most of) the verify phase, it looks rather like a problem of overall operation of the core than an accidental data error, contradicting some of your previousls reported observations.

But I don't remember all details of test driver operation and don't have a hardware at hand to check it now. Also, some details may have changed from V7.2 that I used.

A detailed analysis must check the signal tap results exactly and can't be done on the screenshots. The test driver top design is almost simple, you should be able to trace it to the point where pnf_persist should go high but doesn't.