RE: Understanding higher than expected current draw

Stefan Birnir Sverrisson — Wed, 01 Apr 2015 12:47:49 GMT

Do you have a chance to run your custom code on standard development board, e.g. the nRF51 DK? If so, check what the current consumption is on that board in order to detect if this is a hardware or software problem. To further verify if the problem is caused by your custom board or not, try to run this example without softdevice, where you should be seeing ~3uA when you have pressed button 0.

Try to disconnect any GPIOs from you board in order to see if the current consumption goes down.

Also make sure you have the debug interface disconnected when measuring current.

When you initialize the softdevice, you select which 32kHz clock source to use and that clock source is used until the softdevice is enabled. It is not possible to disable the 32kHz crystal when the softdevice is enabled. Anyway, the crystal should consume ~0.4uA so that is not the source for that high current consumption. After you have disabled the softdevice you can disable the 32kHz clock with

NRF_CLOCK->TASKS_LFCLKSTOP = 1;