Low power modes

RE: Low power modes

Simonr — Tue, 31 Aug 2021 13:08:36 GMT

1 a) When the device is connected it will be in a connected state. It will still be idle between connection upkeep and data transmissions to keep the current consumption as low as possible.

b) I'm not sure I understand. It will be in IDLE mode in-between radio operations, and active in-between. Please check out the Online Power Profiler and tweak the BLE settings however you'd like to see how the device will behave.

2. We have current consumption scenarios explained here where one of them is while having the RTC (real time counter) running to wake up after X amount of time. Then the deivce will be in system ON idle mode and draw ~1.9µA if nothing else is enabled/running.

3. In most of our SDK examples we go to system ON IDLE mode by calling the idle_state_handle() function which does the below (flushes the log, prepares the device to sleep and puts it in IDLE mode with the power management library (see nrf_pwr_mgmt.c/.h in the SDK).

static void idle_state_handle(void)
{
    NRF_LOG_FLUSH();
    nrf_pwr_mgmt_run();
}

Best regards,

Simon

RE: Low power modes

vinaysingh — Tue, 31 Aug 2021 04:37:38 GMT

Hey Simonr, sorry for late reply !

I have few questions more :-

1.) In System On mode, when there is no event pending then the device is in IDLE mode.

a.) But what should we consider when the BLE Device is connected to and mobile App, it is also event going on right ?

b.) So In which Low Power mode the BLE device will be in ?

2.) If any timer is running and executing any Object handler, then that time the device will be in System ON IDLE Mode ?

3.) Can you please share something, How IDLE Mode is implemented in System ON State ?

(I am not able to understand, how exactly the SYSTEM ON IDLE Mode is implemented)

Thank You !

RE: Low power modes

Simonr — Tue, 10 Aug 2021 12:23:17 GMT

1. The nRF52 series SoCs has three "main" power consumption modes. "Regular" system ON mode, which it uses when the application is running, this generally draws quite a bit of power compared to the low power modes. System ON IDLE mode, this is typically the Ultra-low power modes described as System ON in our PS. Finally, we have the System OFF mode, which turns the CPU off completely and uses the least power.

2. In our SDK, we havea couple of "common" functions for dealing with these sleep modes. By default the device will be in the System ON mode. To put it in IDLE mode, we generally use the idle_state_handle() function in the SDK which handles pending log operation s before calling the nrf_pwr_mgmt_run() function that uses the power management library to put it into idle mode.

This goes for system OFF mode as well, which can be reached by calling the sleep_mode_enter() function, which prepares the device for system OFF mode before turning the CPU off.

3. The ble_app_pwr_profiling or power management examples both show how to minimize current consumption.

Best regards,

Simon