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  3. AR# 33403: MIG v3.2, Virtex-6 FPGA DDR2/DDR3 - Simulation warnings are generated for mismatches in port connection sizes

AR# 33403

MIG v3.2, Virtex-6 FPGA DDR2/DDR3 - Simulation warnings are generated for mismatches in port connection sizes

Description

When simulating the MIG v3.2 Virtex-6 DDR3 and DDR2 SDRAM UDIMM designs, the following warnings are generated:

 # ** Warning: (vsim-3015) sim_tb_top.v(608): [PCDPC] - Port size (1 or 1) does not match connection size (2) for port 'cs_n'. 

 # ** Warning: (vsim-3015) sim_tb_top.v(608): [PCDPC] - Port size (1 or 1) does not match connection size (2) for port 'odt'

Solution

These warnings occur because of signal port width mismatches in the sim_tb_top.v testbench module. 

For UDIMM designs, the CS and ODT signal widths are 2. 

However, in the testbench (sim_tb_top.v) only 1 bit is port mapped to the memory model instance.

To work around these warnings, replace the following code in the sim_tb_top.v module: 

Original Code 

.cs_n (ddr2_cs_n_sdram), 
.odt (ddr2_odt_sdram)


Workaround  

.cs_n (ddr2_cs_n_sdram[i/8]), 
.odt (ddr2_odt_sdram[i/8])


These changes to the sim_tb_top.v module are included in MIG v3.3, available with ISE Design Suite 11.4.

AR# 33403
Date 08/14/2014
Status Active
Type General Article
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