sleep current during BLE advertising

[bios-bob]

i'm measuring approximately 1.5uA (at 3V3) when sleeping between BLE advertising events, using a program based on one of your the standard examples....

as an experiment, i built a trivial simple program that retains only SRAM blocks 0-1, enables the LFXTAL, and starts the RTC....  when sleeping, this program consumes about 1.68uA....

so now i'm curious as to what is *NOT* power/enabled/retained while the BLE program is sleeping???  

[Vidar Berg]

Hello,

The softevice is not doing anything "hidden" to reduce power consumption in idle mode, and there are no peripherals that would increase the idle current by this little when active. The only configuration I can think of that could cause changes in current draw at this level is RAM retention. The current consumption is typically around 30 nA per 4k of retained RAM.

Are you measuring on the same chip in both cases, and at exactly the same temperature? Note that ambient temperature can have a significant impact on sleep current.

Best regards,

Vidar

[bios-bob]

same device, with measurements taken in quick succession....  i agree with your RAM retention theory....  is there any way to find out exactly how much RAM is retained by the stack???