Altera PowerPlay Early Power Estimator User Manual

Page 37

Chapter 3: Using Cyclone III PowerPlay Early Power Estimator

3–25

Factors Affecting PowerPlay Early Power Estimator Accuracy

PowerPlay Early Power Estimator User Guide for Cyclone III FPGAs

In this example, you must estimate the following:

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Data toggle rate

■

Mod input toggle rate

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Resource estimate for Decoder module

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Resource estimate for RAM

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Resource estimate for Filter

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Resource estimate for Modulator

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Resource estimate for Encoder

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Toggle rate for Decoder module

■

Toggle rate for RAM

■

Toggle rate for Filter

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Toggle rate for Modulator

■

Toggle rate for Encoder

These estimates can be performed in the following ways:

■

If similar modules were used in the past with data inputs of roughly the same
toggle rate, you can leverage that information.

■

If there are MATLAB simulations available for some blocks, you can obtain the
toggle rate information.

■

If the HDL is available for some of the modules, you can simulate them.

■

If the HDL is complete, the best way to determine toggle rate is to simulate the
design.

The accuracy of toggle rate estimates depends heavily on the accuracy of
the input vectors. Therefore, determining whether or not the simulation
coverage is high gives you a good estimate of how accurate the toggle rate
information is.

The Quartus II software can determine toggle rates of each resource used in the
design if you provide information from simulation tools. Designs can be simulated in
many different tools and information provided for the Quartus II software through a
signal activity file (.saf). The Quartus II PowerPlay Power Analyzer provides the most
accurate power estimate. You can use the comma-separated value file (.csv) from the
Quartus II software with the PowerPlay Early Power Estimator for estimating power
after the design is complete.