RE: System on and keep RTC running in ultra-low power

user20009 — Fri, 10 Jun 2022 12:04:56 GMT

Hi Jørgen,

I try to disable peripheral function. Power saving is under 1mA. But, it's still too high. I try to separate some code to check sleep current. Therefore, I still have few questions.

1. I comment BLE initial function code as below:

Before this, I don't run timer2_init() function (means comment timer2_init()), sleep current can be near 1uA. When I remove comment on timer2_init() (means run timer2_init()), and I disable and run un-initial timer2 before sleep. It's measured about 45uA. How do I close it?

//uart_init();
  log_init();

  timers_init();

  drv_gpio_configuration();
  
  pwm_init();
  
  saadc_sampling_event_init();
  saadc_init();
  timer2_init();      // Question 1
  
  /* Question 3
  sync_rtc(22, 6, 8, 20, 02, 55);
  lfclk_config();
  rtc_config();*/
  
  power_management_init();
  /* Question 4 comment for checking peripheral sleep current
  ble_stack_init();
  gap_params_init();
  gatt_init();
  services_init();
  advertising_init();
  conn_params_init();*/

2. Base on above code, I can't wake up SoC after entering system on mode. In previous wake up code, it works in system off. Instead of sd_power_system_off() to using WFE and WFI, it is ARM low-power standby mode. It should be triggered by events for waking up. But, it looks like not working in my GPIO wake up pin.

3. Enable comments at Question 3 block (RTC) and comment timer2_init() in above code. The current measured 11uA. It is not near 1.9 uA.

4. Reserve RTC function (Question 3) and enable Question 4, and I don't enable advertising in this part. It has 820uA. Which function should be disabled?

Please assistance me to solve it.

Thank you.

RE: System on and keep RTC running in ultra-low power

user14926 — Thu, 09 Jun 2022 13:22:06 GMT

Hi,

It is possible to run the RTC in System ON mode, but not in System OFF. The expected current consumption is given by I_{ON_RAMOFF_RTC} in Current consumption: Ultra-low power, but note that any additional running peripheral will increase the current consumption, as entering System ON mode will not automatically power down peripherals.

If you are measuring 2.x mA current, some additional peripherals must be running. The usual suspects at this current-level is for instance UARTE in receive mode, or the SAADC peripheral.

Best regards,
Jørgen