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AR# 39929

MIG v3.6-v3.61 Virtex-6 DDR3 - tRC violations occur in simulation when # of banks is increased


MIG v3.6-v3.61 Virtex-6 DDR3 designs will fail with tRC violations during simulation only for x16 components if the # of Banks is increased to greater than 4.

The following code changes are required to increase the # of Banks:
parameter BM_CNT_WIDTH =3; (in sim_tb_top.v)
parameter nBANK_MACHS =5; (in memc_ui_top.v)

Simulation Error Messages seen:
# Calibration Done
# sim_tb_top.comp_inst.mem_rnk[0].mem_16.gen_mem.gen_mem[0].u_comp_ddr3.cmd_task: at time 57512599.0 ps INFO: Refresh
# sim_tb_top.comp_inst.mem_rnk[0].mem_16.gen_mem.gen_mem[0].u_comp_ddr3.cmd_task: at time 57622599.0 ps INFO: Activate bank 0 row 0000
# sim_tb_top.comp_inst.mem_rnk[0].mem_16.gen_mem.gen_mem[0].u_comp_ddr3.chk_err: at time 57632599.0 ps ERROR: tRC violation during Activate to bank 0
# sim_tb_top.comp_inst.mem_rnk[0].mem_16.gen_mem.gen_mem[0].u_comp_ddr3.cmd_task: at time 57632599.0 ps ERROR: Activate Failure. Bank 0 must be Precharged.


This issue occurs because the BM_CNT_WIDTH parameter is not being passed from the sim_tb_top module to the example_top. The workaround is to pass the BM_CNT_WIDTH to the example_top instantiation in sim_tb_top.v as shown below:

example_top #
.tCK (tCK),

This is fixed in 13.1 with MIG v3.7.
AR# 39929
Date Created 02/16/2011
Last Updated 12/15/2012
Status Active
Type General Article
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