nfr51 sleep mode and reconnect example

[garypty]

I am going to develop an application on nfr51422 that requires very low current consumption. Basically we plan to make the nfr51 to "sleep", and it will wake up constantly (may be every second) to send out a few bytes through ble.

I would like to ask if there is any example that shows how to make the nfr51 sleep and wake up? Also, I think in the sleep mode, the ble is disconnected. How can make it connects to the mobile device automatically during the "wake-up" period?

Currently I am testing it with the nfr51-DK.

Thank you.

[Jørgen Holmefjord]

Hi,

In general there are two sleep modes in the nRF51-series; system on and system off mode. See chapter 12.1.5-12.1.7 in the nRF51 Reference Manual for more details about the two sleep modes.

Most of the examples in our SDK use sleep functions, by calling the function power_manage() in a loop within the main function. I would recommend that you have a look at this thread about minimize current consumption for BLE application on nRF51822. I would also recommend that you have a look at the Application Timer tutorial if you want to configure your device to wake up regularly to transmitt data.

Read the answer in this thread about keeping connection during sleep mode.

Best regards,

Jørgen

[garypty]

Is that means when the SDK example call the power_manage(), it enters the System On sleep mode already? I have visit this sile: Online Power Profiler, the current consumption in IDLE time is assumed to be 2uA, is it also a System ON sleep mode? Thank you.

[Jørgen Holmefjord]

Yes, power_manage() calls the softdevice API function sd_app_evt_wait(), which will put the device in system on sleep mode. The Online Power Profiler use the ble_app_pwr_profiling example from the SDK, which also use this method to put the device into system on sleep mode between advertising or connection intervals.

[garypty]

I tested the Application Timer Tutorial with keil5, SDK11, however I cannot build it successfully. The error message says it cannot find "app_timer.h", which is included in the main.c

[Jørgen Holmefjord]

Did you remember to add the include path to the project?

Now go to Project -> Options for target ... -> C/C++. 
From there, add the following directories to the Include Paths:

..\..\..\..\..\components\drivers_nrf\clock
..\..\..\..\..\components\libraries\timer
..\..\..\..\..\components\drivers_nrf\delay