Enter in SYSTEM ON doest not work

[Louis Hatte]

Hello everyone,

I'm using the nrf52840 Dev Kit (PCA10056 1.1.0 2019.19 683465548)

SDK version: 15.3

OS: Fedora

I work on a custom board and try to put it in SYSTEM ON mode like so:

int main(void)
{
    log_init();
    NRF_LOG_INFO("App start\n");
    NRF_LOG_FLUSH();

    power_management_init();
    for (;;) {
        nrf_pwr_mgmt_run();
    }
}

When I measure my consommation with OTII I get 4 mA instead of 1.5 uA according to this link (Debugging: Section 4).

Any ideas?

Regards,

Louis

[Simonr]

Are you struggling to disable the UART properly, because you won't be able to transmit over UART and keep a current consumption below 10uA?

What UART do you have enabled? Erratum 89 describes a problem where you have to power cycle some of the peripherals using EasyDMA in order to disable them properly, please see this post for instructions on that with UARTE or UARTE1. Keep in mind that you have to reinitialize the UARTE peripheral again in order to turn it back on.

You could also use UART without EasyDMA in order to avoid this altogether.

Best regards,

Simon

[Louis Hatte]

Hi Simon

Your post resolved my issue. I have now 6µA consumption in SYSTEM ON mode on my main project.

Thanks for your help!