AR# 50858: MIG Virtex-5 DDR2 Dual Rank - Incorrect Pre-charge issued when switching ranks causing data errors
MIG Virtex-5 DDR2 Dual Rank - Incorrect Pre-charge issued when switching ranks causing data errors
The Virtex-5 DDR2 Dual Rank design has been found to incorrectly issue a pre-charge when switching between ranks. Because the controller mistakenly sends the pre-charge, an activate is not sent to the closed location, causing data errors in both simulation and hardware. This issue will be seen in all MIG versions of the Virtex-5 dual rank design.
The issue found is within the bank management logic of the controller logic. A fix has been identified and fully tested. The issue and subsequent fix are displayed here:
The fix and corresponding instructions can be downloaded from the link at the bottom of this answer record.