Energy Consumption of nrf52832

[Patrik Zajaczkowski]

Dear Nordic Team,

we are developing a system with Bluetooth Low Energy and Zigbee capabilities (using the TI CC2630 microcontroller as Zigbee external communication device). In order to support BLE and Zigbee communication in parallel we have enabled the multiprotocol feature (Nordic Time-slot API) available at Softdevice and created a protocol based on GPIO and SPI on both microcontrollers. Additionally, our target is to be as energy efficient as possible to reach one year of battery life in our product. That means that every measured microampere in power consumption is important.

Our problem ist that during the energy measurements we found that there is a difference of 0,5 mA in the current consumption between two firmwares (exactly the same commit number) , one configured with multiprotocol functionalities enabled and the other with multiprotocol disabled. This difference causes a significant negative influence on the power consumption of our system which reduces our battery lifetime and the estimated battery time.

•  Question: Does the Softdevice need a higher current consumption when the Timeslot API is enabled?
  • If yes: How high is the difference?
  • If no: What are the optimization points to reduce this 0,5 mA difference to the minimum?

Please give us response as soon as possible if you need further infos to answer the questions.
Thanks a lot in advance!

[Simonr]

Hi

This difference seems like the high frequency clock (HFCLK) is running in your application. Do you need the HFCLK for the multiprotocol functionalities? I recommend you use the register directly to control the HFCLK to turn it off when not needed at least. 

if (!(NRF_CLOCK->HFCLKSTAT & CLOCK_HFCLKSTAT_SRC_Msk))

{

  NRF_CLOCK->TASKS_HFCLKSTART = 1;

  NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;

  while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0);

}

As for your initial question, no the SoftDevice should not consume more power using the Timeslot API specifically.

This post explains just about everything there is to know about reducing current consumption, so I suggest you take a look to find the best ways to do this.

Best regards,

Simon