Fitter Error Occurs When Read DQS Tracking is Enabled

Description

This problem affects DDR2 and DDR3 products.

In version 11.1 SP1, a Fitter error occurs when Read DQS Tracking is enabled.

Resolution

The workaround for this issue is to add the following in lines 1005-1006 of altdq_dqs2_stratixv.sv :

always @(negedge dqs_disable_int) dqs_ff <= dqsin;