RTC turns off when using idle_state_handler in ble_app_template

[ThomasN12]

Hi

Im developing an application that will wake up on RTC every 15 minutes. My issue is that when using idle_state_handle, which in turn calls sd_ble_app_wait, the RTC will turn off, and therefore will not wake up from this source. This is verified using prints to a terminal. Ive tried using both app_timer and configuring RTC2 myself, both have the issue. 

My question is how can i configure the sd_ble_app_wait to first of all not turn off the RTCs  and second of all, how can i choose to wake up from RTC?

Im on windows, using SDK17 on a 52840 using a devkit PCA10056. 

[ThomasN12]

Thank you for these answers, they are very helpful. i ahve managed to implement it succesfully.

Another question that is springing to mind is numbers regarding the current consumption when running from a DCDC vs LDO in sleep mode. The numbers specified in the datasheet are only shown for an LDO, but im curious to know how using the internal DCDC converter will affect these numbers or if it has any effect at all. I can see nubmers are specified for when the CPU is running, but since it will spend most of its time in sleep, these numbers are of smaller significance. 

[haakonsh]

ThomasN12 said:

these numbers

 What numbers? 

[ThomasN12]

The current consumption for the active state is of less significance, since the board will only be active for small timeslots. But when its sleeping for such elongated periods the sleep current is now of larger importance. There are however only current consumptions listed for LDO usage and not DCDC for sleep. Will they be the same or will it be lower for DCDC compared to the LDO?

[haakonsh]

The LDO is more efficient at low current consumption. The DCDC is only used when the current consumption is high, like when the CPU or RADIO is running, otherwise, it is turned off. This is automatically handled and you don't need to do anything. 

I suggest you measure the current consumption on the DK running your code with and without the DCDC and compare the results.