nRF52840 Dongle BLE Power Optimization

RE: nRF52840 Dongle BLE Power Optimization

Stian Røed Hafskjold — Fri, 12 Jul 2019 11:07:08 GMT

So, the CPU never stops running unless you tell it to stop. 6mA is the expected current when the CPU is running. Just having a main function without a while loop, means that the CPU will exit main and continue running some random place in memory and most likely hardfault. So you need a while loop. If you put __WFE() inside that while loop, the CPU will pause and wait for an event (WFE = wait for event) to continue. So the source code for the lowest consumption will be like this:

int main(void){
    while(true){
        __WFE();
    }
}

RE: nRF52840 Dongle BLE Power Optimization

Fabio — Wed, 10 Jul 2019 03:31:43 GMT

can you post the source code for this? I am playing with the dongle and created an empty main() without even a while loop and am getting 6mA of consumption. I don't understand how you guys are getting anything in uAs! Are you modifying the dongle hardware? Can you point me in the right direction?

RE: nRF52840 Dongle BLE Power Optimization

Stian Røed Hafskjold — Thu, 04 Apr 2019 15:06:57 GMT

Hi, it's not clear to me what the connection interval is. You say that you set the max and min connection interval to 10ms and also changing from 0 to 99. The connection interval is decided by the central device. And you should be able to set this in nRF connect.

The TASKS_LOWPWR is the default setting, it just reverts back to low power mode if it was set to constant latency earlier. So this is not something you have to worry about if you haven't used constant latency mode.

Have you enabled DCDC on both REG0 and REG1? You can enable both in the start of main(), you don't have to wait until right before advertising.