04-18-2013 03:24 AM
I am using Xpower to generate power consumption estimation. I simulate my architecture and then i generate the vcd file on many period. VCD files are used by Xpower to generate its output. While looking to the output file, there is estimation about power consumed but there is and error at the end ERROR paragraph which is:
ERROR:Power:1653 - Duty cycle <200.00> must be in range [0..100]% for "signal"
I don't know from where it is generated or if really there is a problem on running Xpower maybe. I need some help please.
04-18-2013 09:05 AM
200% toggle rate is usually inferred if there are DDR (dual data rate) IO....
DDR switches once on the rising edge, and again on the falling edge. So that is two changes per clock period for the clock itself.
04-19-2013 06:21 AM
Thank you austin for your response.
Actually i don't use any DDR in my design. I can't see why this error is generated.It affects the value of the power estimated ?
04-19-2013 07:19 AM
Yes. Dynamic power is F*C*V^2 (frequency, times capacitice, times voltage squared).
Frequency in this case is toggle rate. So, for a 100 MHz clock, that is 100%.
For the LSB of a counter, on 100 MHz clock, that is 1/2 100 (50% duty cycle), or 50 MHz....etc.
Yoy may not think you have any DDR, but the only way to know is to examine every clock domain, and look at what you have. You may have IP blocks that you did not create, so how do you know what is in them? You examine the reports.
04-22-2013 03:02 AM
Thank you for this explication. Now i understood the meaning of the Duty cycle. But till now i am not able to find the solution . For example, i have this error for an input on my top level module which i initialize it manually at the begining of the simulation and i am not modifying it anymore:"ERROR:Power:1653 - Duty cycle <200.00> must be in range [0..100]% for but_i<0>"
I am using VCD files generated by Modelsim 10.2 as input for xpower. You find attached the report generated by Xpower.
11-17-2014 12:43 AM
Try generating SAIF file using Isim and using it in Xpower Analyzer instead of VCD file. You may not get this error any more.