Description

Version Found: DDR4 v1.0, DDR3 v1.0

Version Resolved: See (Xilinx Answer 69035) for DDR4, See (Xilinx Answer 69036) for DDR3

For some DDR4/DDR3 IP configurations the VCS simulator will fail with the following data errors:

sim_tb_top.mem_model_x4.memRank[0].memModel[0].u_ddr3_x4.data_task: at time 6046689.0 ps ERROR: DQS bit 0 latching edge required during the preceding clock period.
sim_tb_top.mem_model_x4.memRank[0].memModel[0].u_ddr3_x4.data_task: at time 6046689.0 ps ERROR: DQS_N bit 0 latching edge required during the preceding clock period.
sim_tb_top.mem_model_x4.memRank[0].memModel[3].u_ddr3_x4.dqs_neg_timing_check: at time 6047862.0 ps ERROR: tDQSH violation on DQS bit 0
sim_tb_top.mem_model_x4.memRank[0].memModel[3].u_ddr3_x4.dqs_neg_timing_check: at time 6047862.0 ps ERROR: tDQSH violation on DQS_N bit 0

ERROR: Expected data=010801080108010801080108010801080108010801080108, Received data=000800080000000000080008000000000008000800000000 @ 7002551.0 ps
ERROR: Expected data=011001100110011001100110011001100110011001100110, Received data=001000100000000000100010000000000010001000000000 @ 7015920.0 ps
ERROR: Expected data=011801180118011801180118011801180118011801180118, Received data=001800180000000000180018000000000018001800000000 @ 7029288.0 ps
100 Writes and 100 Reads to the memory completed
TEST FAILED: DATA ERROR

This issue only occurs with VCS simulators when run from the Vivado GUI.

All other supported simulators and VCS run stand-alone are not affected.

Solution

The errors are caused by an issue with the VCS "-debug_pp" switch and not with Vivado or the DDR4/DDR3 IP.

To work around the issue when using the IP Example design, follow the steps below:

1. Generate the DDR4/DDR3 IP


2. Open the IP Example Design


3. Under Simulation Settings, Select VCS simulator as the Simulator
• Map the libraries for VCS
• Select the option to Generate scripts only
4. Go to the "example_design/example_design.sim/sim_1/behav" directory


5. Open the elaborate.sh file and modify the line from:
   

"vcs_opts="-full64 -debug_pp -t ps -licqueue -l elaborate.log""

Modify the line to:

"vcs_opts="-full64 -debug_all -t ps -licqueue -l elaborate.log""

6. Run ./compile.sh


7. Run ./elaborate.sh


8. Run ./simulate.sh

Revision History:

09/30/2015 - Initial Release

Linked Answer Records

Master Answer Records