Device Family: Stratix® IV E

Type: Answers

Area: EMIF, Intellectual Property


IP Product: DDR3 SDRAM Controller MegaCore supporting UniPHY

Why do I get a hold time violation when compiling my Stratix IV DDR3 SDRAM UniPHY based controller design in the Quartus II software version 11.0SP1?

Description

When compiling a Stratix IV DDR3 UniPHY design in the Quartus® II software, you may get hold time violations between the core clock (afi_clk which is the CLK[0] output of the PLL) and the leveling clock (memphy_leveling_clk which is CLK[2] output of the PLL).

The hold time violations are caused by skew between the core clock which is on a dual regional clock resource and the leveling clock which is on a global clock resource.

Workaround/Fix

To work around this issue, assign memphy_leveling_clk clock signal to a dual regional resource.