Power estimation for programmable devices like FPGAs is a complex process, because it is highly dependent on the amount of logic in the design and the configuration of that logic. To produce accurate estimates, the power estimation process requires accurate input values, such as resource usage, clock rates, and toggle rates. To supply the minimum input that will allow XPE to estimate power with reasonable accuracy, you need the following:
- A target device-package-grade combination
- A good estimate of resources you expect to use in the design (for example, flip-flops, look-up tables, I/Os, block RAMs, DCMs or MMCMs, and PLLs.)
- The clock frequency or frequencies for the design
- An estimate of the data toggle rates for the design
- The external memory and transceiver based interfaces with their data rates for the design
- The thermal environment in which the design will be operating
As a general rule, input as much information about your design as available, then leave the remaining settings to default values. This strategy will allow you to determine the device power supply and heat dissipation requirements.
Tip: Use Excel formulas to link different cells together. For example, type '=CLOCK!E10' in the Clock cells of the Logic sheet, which lists the resources driven by this clock domain.