NRF52840 DONGLE NCS 2.7.0 LOW POWER MODE

[krypton76]

I'm trying to activate low power mode without success.
I found samples but it appears not to work with the last NCS version.

I want to get basic GPIO INPUT values at 32khz timer resolution. I get values with GPIO interruption during 100ms and send an average values on ESB radio, then the device get back to sleep for  1 second and read the signal again.

I'm lost in CONFIG_PM / CONFIG_PM_DEVICES and all parameters i should set in order to get less then 1mA during passive GPIO READS and then get less then 10uA during sleep mode.

-- CMake version: 3.21.0
-- Cache files will be written to: /Users/lilianbrun/Library/Caches/zephyr
-- Zephyr version: 3.6.99 (/opt/nordic/ncs/v2.7.0/zephyr)

In particular i can't use pm_state_force function, even with 

CONFIG_PM_DEVICE=y in prj.conf and 

#include <zephyr/pm/pm.h>

#include <zephyr/pm/policy.h>

#include <zephyr/pm/state.h>

#include <zephyr/pm/device.h>

I Power the device with PPK2 as 3.3V on VDD OUT pin, i cut SB2 and soldier SB1

[krypton76]

As i understood, CONFIG_PM is deprecated and pm_state_* functions too.

So i start a new simple project : 

#include <zephyr/kernel.h>
#include <zephyr/device.h>
#include <hal/nrf_rtc.h>
#include <zephyr/pm/device.h>
#include <zephyr/logging/log.h>

LOG_MODULE_REGISTER(main, LOG_LEVEL_INF);

// Configuration RTC
#define RTC NRF_RTC1
#define RTC_FREQUENCY 32768    // Fréquence de l'horloge RTC (32.768 kHz)
#define TIMEOUT_MS 900         // Temps d'attente en millisecondes
#define TIMEOUT_TICKS (TIMEOUT_MS * RTC_FREQUENCY / 1000)

volatile bool rtc_timeout = false;

// Liste des périphériques à désactiver
const char *devices_to_disable[] = {
    "UART_0",
    "UART_1",
    "SPI_0",
    "SPI_1",
    "I2C_0",
    "I2C_1",
    "PWM_0",
    "PWM_1",
    "ADC_0",
};

// Gestionnaire d'interruption RTC
void rtc_handler(void)
{
    if (nrf_rtc_event_check(RTC, NRF_RTC_EVENT_COMPARE_0)) {
        nrf_rtc_event_clear(RTC, NRF_RTC_EVENT_COMPARE_0);
        rtc_timeout = true;
        LOG_INF("RTC timeout reached");
    }
}

void RTC1_IRQHandler(void)
{
    rtc_handler();
}

// Configurer le RTC pour générer une interruption après TIMEOUT_MS
static void configure_rtc(void)
{
    nrf_rtc_prescaler_set(RTC, 0);  // Pas de division, fréquence à 32.768 kHz
    nrf_rtc_cc_set(RTC, 0, TIMEOUT_TICKS);
    nrf_rtc_event_enable(RTC, NRF_RTC_INT_COMPARE0_MASK);
    nrf_rtc_int_enable(RTC, NRF_RTC_INT_COMPARE0_MASK);
    nrf_rtc_task_trigger(RTC, NRF_RTC_TASK_CLEAR);
    nrf_rtc_task_trigger(RTC, NRF_RTC_TASK_START);

    NVIC_ClearPendingIRQ(RTC1_IRQn);
    NVIC_SetPriority(RTC1_IRQn, 1);
    NVIC_EnableIRQ(RTC1_IRQn);

    LOG_INF("RTC configured for timeout of %d ms", TIMEOUT_MS);
}

// Désactiver les périphériques inutiles pour réduire la consommation
static void disable_unused_devices(void)
{
    for (int i = 0; i < ARRAY_SIZE(devices_to_disable); i++) {
        const struct device *dev = device_get_binding(devices_to_disable[i]);
        if (!dev) {
            LOG_WRN("Device %s not found", devices_to_disable[i]);
            continue;
        }

        if (pm_device_action_run(dev, PM_DEVICE_ACTION_SUSPEND) == 0) {
            LOG_INF("Device %s suspended", devices_to_disable[i]);
        } else {
            LOG_WRN("Failed to suspend device %s", devices_to_disable[i]);
        }
    }
}

void main(void)
{
    LOG_INF("Starting low-power mode with RTC wakeup");

    // Configurer le RTC
    configure_rtc();

    // Désactiver les périphériques inutilisés
    disable_unused_devices();

    while (1) {
        rtc_timeout = false;

        LOG_INF("Entering low-power mode for 900 ms...");
        k_sleep(K_MSEC(900));  // Le système entre en System ON Idle ici

        // Attendre que le RTC atteigne son timeout
        while (!rtc_timeout) {
            k_sleep(K_MSEC(1));
        }

        LOG_INF("Woke up from low-power mode");
    }
}

# Enable GPIO and RTC
CONFIG_GPIO=y

# Enable power management
CONFIG_PM_DEVICE=y

# Optimize stack sizes
CONFIG_MAIN_STACK_SIZE=1024
CONFIG_IDLE_STACK_SIZE=256

# Disable unnecessary logging to save power
CONFIG_PRINTK=n
CONFIG_CONSOLE=n
CONFIG_SERIAL=n
CONFIG_LOG=y

And i works a bit, but i get a constant average consumption of 214uA, which is far more than expected, regarding what it does.