System ON mode: Bluetooth Event Wakeup: NRF52832

[NileshK]

HI All,

We are using NRF52832 for our project.

1) We are using System ON mode to put NRF52832 in to sleep mode. We are able to put NRF52832 in to sleep mode(System ON mode) successfully. Though current consumption in sleep mode is much higher ie 20mA. 

When sleep condition is satisfied we are calling the below API to enter into System ON mode. We are not turning off any peripherals explicitly. what is the typical current consumption in system ON mode and how do we achieve?

Pseudocode:

if(sleep_condition_satisfied)

{

    ChipEnterSystemONMode();

}

void ChipEnterSystemONMode(void)
{
     /*Enter System ON Mode*/
    sd_app_evt_wait();
}

2) Can we wake up the NRF52832 chip from sleep mode(System ON) using Bluetooth Event?

     If yes, how to wake it up?

    We are not able to wake up NRF52832 from sleep mode(System ON) using Bluetooth Event currently.  

    Do we have to prepare for Bluetooth wakeup before entering in to sleep mode.

Please send some example/sample code for the same.

Thank you.

[Simonr]

Hi

20mA current consumption shouldn't be possible for the nRF52832 to draw on its own, not even when advertising/scanning with the radio peripheral.

1. With the CPU just running (not in sleep mode) that should consumpe somewhere between 3.3 and 8.0 mA depending on whether it's running from Flash or RAM and what regulator is used.

In system ON sleep mode, you shouldn't see more than a 2.0µA current draw from the nRF52832. 

2. No, when the nRF52832 is in sleep mode, the radio peripheral will be turned off, so it will not be able to register any incoming BLE activity. It can be woken by a power reset, a GPIO event (like a button press or external physically connected device), on RTC events or on NFCT events. With I.E the RTC, you can wake it up say every 10 seconds and start the radio peripheral so it can transmit or scan for Bluetooth events.

Best regards,

Simon

[NileshK]

2. Please send example/sample code for RTC events (Real time Counter) for wake up from sleep mode.

With I.E the RTC, you can wake it up say every 10 seconds and start the radio peripheral so it can transmit or scan for Bluetooth events.

Thanks

Nilesh

[Simonr]

Hi

What SDK are you using for development? The nRF Connect SDK or nRF5 SDK? We have an example project using the RTC here for the nRF5 SDK at least. It doesn't do BLE by default, but it shouldn't be too hard to implement in one of the existing BLE example projects.

Best regards,

Simon

[NileshK]

I think we are using nRF5 SDK for out development .

nRF_Softdevice: S132_nrf52_2.0.0-7. alpha_license_agreemnt.tx

I have another question:

Can we use RTC(Real time counter) for waking up  from sleep mode (Assuming we use any of the mode ie System ON as well as System OFF mode)?

Please confirm with system OFF mode we can use RTC to wake it Up?

Please confirm with system ON mode we can use RTC to wake it Up?

Steps we want to follow:

1) Put the system in sleep mode using system OFF mode

2) Use RTC (Real time counter) to wake it up every 10 seconds or something 

3) After wake it up, start the radio peripheral so it can transmit or scan for Bluetooth events.

4) If it detects Bluetooth event, perform regular operation

5) If it does not detect Bluetooth event, again go sleep, After 10 seconds, it will wake up.

Best regards,

Simon

[Simonr]

Hi

RTC can only wake up the nRF52 from system ON sleep mode, as the RTC is a peripheral in the nRF52, it will have to be ON for the RTC to run (and thus wake up the nRF).

You will have to put it in sleep "system ON" mode for this to be possible. Other than that this is possible to do. Depending on what you'd like to do I think one of the central applications should suit what you'd like to do, and then add the RTC sleep functionality to that.

Best regards,

Simon