Device Family: Stratix® III, Stratix® IV

Type: Answers, Errata

Area: EMIF, Intellectual Property, Tools



Calibration Failure Occurs when RELEASE_CLEARS_BEFORE_TRI_STATES is On

Description

This problem affects DDR2 and DDR3, LPDDR2, QDR II, and RLDRAM II products.

UniPHY-based memory interfaces generated in the Quartus II software version 11.0 or later and targeting Arria II GZ, Stratix III, or Stratix IV devices will experience calibration failure if the following setting is included in the project’s QSF file:

set_global_assignment -name RELEASE_CLEARS_BEFORE_TRI_STATES ON

For Uniphy-based memory interfaces generated in the Quartus II software version 12.0 or later and targeting Arria II GZ, Stratix III, or Stratix IV devices, the following message occurs during timing analysis if RELEASE_CLEARS_BEFORE_TRI_STATES is set to ON:

This design has the QSF assignment RELEASE_CLEARS_BEFORE_TRI_STATES set to ON. UniPHY IP in Stratix III and Stratix IV is not compatible with this setting. Set the RELEASE_CLEARS_BEFORE_TRI_STATES assignment to OFF to resolve the issue.

Workaround/Fix

In all cases, the workaround for this issue is to ensure that the keyword is set to OFF:

set_global_assignment -name RELEASE_CLEARS_BEFORE_TRI_STATES OFF