power consumption nrf52

[Joke]

Hi,

I am trying to figure out the best way to save power on the nrf52. I need to connect with ble about two times per day. The ble should 'woken up' by an accelerator (probably ADXL362), connect, send a small packet, and then go back to sleep.

When I look at the nRF52832 Product Specification I see that System OFF, No RAM retention, Wake on GPIO is about the same consumption as System ON, No RAM retention, Wake on any event. Is this correct? And with the Wake on reset option, how would you tigger a reset?

Can you recommend a consumption model we use for saving as much power as possible? Will we consume more power by using System OFF and restarting ble, rather than keeping System ON?

Thanks in advance

[Sigurd]

Hi,

This is a documentation bug. The correct value for System OFF, No RAM retention, Wake on GPIO is 0.3 μA. i.e. the same value as System OFF, No RAM retention, Wake on reset. In order to save as much power as possible System OFF with NO RAM retention mode is recommended.

You can configure a pin to wake up the chip from SYSTEM OFF like this:

nrf_gpio_cfg_sense_input(YOUR_PIN_NUMBER, NRF_GPIO_PIN_PULLUP, NRF_GPIO_PIN_SENSE_LOW);

Use the function sd_power_system_off() to go to SYSTEM OFF mode.

When the pin goes low, it will generate a signal that will wake up the chip. You can read more about System OFF mode here.