Low power on NRF52 ItsyBitsy

[oxanagig3]

Hello,

I am trying to get the lowest power possible on NRF52 ItsyBitsy, and I saw the discussion regarding the hardware side(LED, LDO, etc..)

My question is that I put the system to system off power state.

Code: Select all

void loop() {
    NRF_POWER->SYSTEMOFF = 1;
}

And have set up the button on the board to wakeup the system. reference: https://github.com/NordicPlayground/nrf ... pio/main.c

Code: Select all

#define  BUTTON 29
nrf_gpio_cfg_sense_input(BUTTON, NRF_GPIO_PIN_PULLUP, NRF_GPIO_PIN_SENSE_LOW);

I can set the system going to system off mode, and wake up by the button, however, the system will enter the Bootloader (DFU) mode, and not return to the APP.

Is this expected behavior? Can I do something to make it go back to the app(I know it won't go back to where it enters power down, because the RAM will be lost)?

[mikeysklar]

@oxanagig3,

Can you trying using waitForEvent() which should put the processor into sleep mode and only bring it back up with memory saved. Whereas SYSTEMOFF would require a full reset to come back to program mode as you are observing.

viewtopic.php?t=126452&p=630709&hilit=nrf52+sleep
https://github.com/adafruit/Adafruit_nR ... ring.h#L34