nrf52840 + Zephyr: How to achieve low current consumption?

[Jakub J.]

Hi

I'm learning Zephyr ecosystem in context of using nRF SoCs. How one can achieve  current consumption values as low as in datasheet ( 0,4 uA in System Off, with no RAM retention, wake on reset)?

I'm measuring current using PPK2 and NRF52840DK and I can reach only 4,24 uA in average.

I'm using blinky sample application as a template.

Whole code is:

void main(void)
{

	while (1) {
		k_sleep(K_FOREVER);
	}
}

And proj.conf is:

CONFIG_GPIO=n
CONFIG_SERIAL=n
CONFIG_LOG=n
CONFIG_CONSOLE=n
CONFIG_UART_CONSOLE=n
CONFIG_RTT_CONSOLE=n
CONFIG_USE_SEGGER_RTT=n
CONFIG_PRINTK=n
CONFIG_PM_DEVICE=y

[Hakon]

Hi,

k_sleep() does not put the CPU in system off. You need to put it in system off explicitly, for instance by writing to the register NRF_POWER->SYSTEMOFF = 1.