AR# 53136

MIG 7 Series QDRII+ - A latch is incorrectly inferred when using Synplify and CPT_CLK_CQ_ONLY=TRUE

Description

Version Found: v1.7
Version Resolved and other Known Issues: See (Xilinx Answer 45195).

All users are now required to manually set the top-level RTL parameter CPT_CLK_CQ_ONLY=TRUE to enable a more reliable read data capture scheme; see (Xilinx Answer 53053). However, when Synplify is used a latch is being inferred for the init state machine output "wrcal_en" which causes the wrong write calibration triggers sent to the PHY. The inferred latch causes write calibration failures in hardware.

Solution

To work around this issue, a small change to the "qdr_phy_write_init_sm.v" module is necessary whichis included ina drop-in replacement patch attached at the end of this answer record.

To install the patch, extract the contents of "AR53136.zip" to the ./user_design/rtl/phy directory of the generated MIG 7 Series design (example: C:\my_ddr_design\user_design\rtl\phy).

Revision History
11/27/2012 - Initial release

Attachments

Associated Attachments

Name File Size File Type
AR53136.zip 12 KB ZIP

Linked Answer Records

Master Answer Records

Answer Number Answer Title Version Found Version Resolved
45195 MIG 7 Series - Release Notes and Known Issues for All ISE versions and Vivado 2012.4 and older tool versions N/A N/A

Child Answer Records

Answer Number Answer Title Version Found Version Resolved
53053 Design Advisory for MIG 7 Series QDRII+ - Read calibration failures can occur when CPT_CLK_CQ_ONLY=FALSE N/A N/A
AR# 53136
Date 03/02/2013
Status Active
Type Known Issues
Devices
IP