Current Measurement for sets of operations

[FA]

Hi,

I'm trying to compare current consumed for different sets of commands mainly with floating point operations in them. As they execute fast, I'm putting them in a loop in simple programs and then I measure the average current for a few seconds.

A sample code is attached here.

I tested this on nRF Beacon kit with SDK 9 and S110. No GPIO and LEDs are used, I reset the board after programming, but the power supply shows constantly ~ 3mA which should not be just for these operations.

When I include power_manage() at the end of the loop the current goes to 0 mA, which shows low current but my loop will only run once and I can not measure the current for those operations.

So, what is causing that 3mA? I assume I must disable some modules which I'm missing.

Also, my measurements are relative, so I don't mind if extra hundreds of uA are included (as long as they are consistent for all programs) but mA seems too much.

As I'm using 32KHz XTAL, I don't think this applies, and even if does it's only 1mA.

Thanks!

[Hung Bui]

@FA: What would you expect the result should be ? When you keep the CPU working (which is your case when you do floating point operation all the time) the CPU consumes 4.1mA. 3mA is a little bit strange.

When you put the CPU to sleep with power_manage() it will stop consume power and you see 0mA. If you want your code to run periodically, you would need to use a timer and wake the chip up with an interval and execute the code.