FPU Current

[WestCoastDaz]

How much additional current does enabling the FPU add to the nRF52 processor? I reviewed the Product Spec. but I can't seem to find this listed anywhere.

Thanks

[Øyvind Karlsen]

Hi,

Running a Digital Signal Processing example that utilizes the FPU we saw one tenth of the power consumption when enabling FPU compared not having it enabled.

Thinking of additional current when enabling the FPU does not give an accurate number for the average power consumption. Since doing floating point operations with the FPU is roughly 20 times faster than doing them without FPU you can spend a lot more time idle, this leads to a lower average power consumption. If we had listed the current that the FPU uses while active it would give an inaccurate number as almost all application will spend different amounts of time doing actual processing.

Best regards,

Øyvind

[WestCoastDaz]

Oyvind,

Our application has very little floating point calculations. I am just trying to compare the cost of keeping the floating point unit enabled all the time for the small amount of time we need it versus having it emulated in software.

Our application isn't a DSP application.

Cheers, Darren