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AR# 30211

ModelSim 6.3c - Unable to observe all the bus bits in a VCD simulation

Description

I attempt to add a bus to a VCD using the "vcd add" command, but I observe only some bits of the bus. For example, I tried to add a 16-bit bus using the command "vcd add /testbench/uut/my_bus", but I can see only the two most significant bits when I load the VCD.  

 

How can I resolve this problem?

Solution

This issue does not apply to situations where "vcd add" is not used. To work around this issue, add "-nopartialatomic" switch to the vsim command line. For example: 

 

vsim -nopartialatomic -do make_power_vcd.do 

 

This issue will be resolved in a future release of ModelSim.

AR# 30211
Date Created 02/06/2008
Last Updated 05/22/2014
Status Archive
Type General Article