Electronic – Estimating power consumption in cadence RTL compiler with VCD file


I need to analyze the power consumption using RTL Compiler based on the VCD file generated by ModelSim. I have two files:

gcm.v (This is the main circuit. Module name is "gcm")

tb.v (This is the testbench. Module name is "tb", and "gcm" is instantiated as "gcm_tb")

The command to generate vcd file is in tb.v as below:

$dumpfile ("testb. vcd");
$dumpvars (1, testbench.gcm_tb);

Here is my script for RTL compiler:

set_attribute lib_search_path /opt/cadence/local/FreePDK45/osu_soc/lib/files
set_attribute library {gscl45nm.lib}
read_hdl -v2001 tb.v
read_vcd -vcd_module gcm_tb -module gcm -static testb.\ vcd    
synthesize -to_mapped 
write -mapped > gcm_synth.v
report power -tcf_summary > power.txt

RTL compiler gives me the same power numbers with and without the VCD file. Here is my power summary in power.txt:

  Generated by:           Encounter(r) RTL Compiler v07.10-p004_1
  Generated on:           Mar 28 2013  03:47:17 PM
  Module:                 ccm
  Technology library:     gscl45nm
  Operating conditions:   typical (balanced_tree)
  Wireload mode:          enclosed

                    Leakage    Dynamic     Total
  Instance   Cells Power(nW)  Power(nW)  Power(nW)
ccm           2963 71474.787 535247.155 606721.942
  add_147_11   127  6038.327  11984.664  18022.991
  a_aes          0     0.000  19505.200  19505.200
  e_aes          0     0.000  26450.600  26450.600

Total nets in design            : 3865 (100.00%)
Nets asserted                   : 0 (0.00%)
Nets computed                   : 3862 (99.92%)
Default nets                    : 0 (0.00%)
Clock nets                      : 0 (0.00%)
Constant nets                   : 3 (0.08%)
Net does not have TCF asserted  : 3865 (100.00%)

I see the nets asserted is 0. Is this the reason why the power consumption did not change?

Thank you!

Best Answer

$dumpvars (1, testbench.gcm_tb); is your problem. To get all the lower-level signals you need $dumpvars (0, testbench.gcm_tb);

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