NRF7002 DK system shutdown

RE: NRF7002 DK system shutdown

Arjun-Prasad — Tue, 22 Jul 2025 21:04:18 GMT

Hello,

I have a similar requirement. I am trying to achieve lowest possible current for both host mcu(nrf5340) and wifi chip(nrf7002). I am using https client example(sdk v3.0.2) and added modification to call sys_poweroff with button wakeup after https request is sent. I notice that the wifi campanion chip draws ~1uA. But nrf5340 seem to draw ~120uA. I have disabled console as well. When I run shutdown example that implements only sys_poweroff without wifi I can achieve <1uA average current on nrf5340. Can you let me know what might be causing higher current when wifi is enabled?

Best Regards,

Arjun

RE: NRF7002 DK system shutdown

Håkon Alseth — Fri, 29 Nov 2024 14:12:22 GMT

Hi,

You see 120 milliamps?

That indicates that something went terribly wrong.

Have you checked that the shutdown-sample works as expected on your end?

I ran the snippet in the sta/ sample and used the shutdown function as shown here:

https://github.com/nrfconnect/sdk-nrf/blob/v2.7.0/samples/wifi/shutdown/src/main.c#L155-L172

And measure < 5 uA when it is shut down.

Kind regards,

Håkon

RE: NRF7002 DK system shutdown

rainbowkenny — Fri, 29 Nov 2024 08:47:51 GMT

In my case, current draw increased from ~10mA to ~120mA when I step in this line inside net_if_down():

status = net_if_l2(iface)->enable(iface, false);

RE: NRF7002 DK system shutdown

rainbowkenny — Wed, 27 Nov 2024 16:21:09 GMT

Ok, I've added a workqueue, so net_if_down() doesn't stuck any more.
However, it doesn't reduce power consumption, in contrast, it increased current draw.
Here's the code:

void system_shutdown()
{
    shutdown_wifi();
	sendMsgToSTM(PacketReply_t_nrf_shutdown_tag);
	k_sleep(K_SECONDS(1));
	sys_poweroff();
}

void watchdog_work_handler(struct k_work *work)
{
    LOG_ERR("Watchdog triggered: handling in work queue");
    system_shutdown();
}

void timer_system_shutdown(struct k_timer *timer_id)
{
	k_work_submit_to_queue(&my_workq, &watchdog_work);
}

K_TIMER_DEFINE(watchdog_timer, timer_system_shutdown, NULL);

void setUpWatchdog()
{
	// Initialize the work queue
    k_work_queue_start(&my_workq, my_workq_stack, 
                       K_THREAD_STACK_SIZEOF(my_workq_stack), 
                       CONFIG_SYSTEM_WORKQUEUE_PRIORITY, NULL);

    // Initialize the work item
    k_work_init(&watchdog_work, watchdog_work_handler);
	LOG_ERR("watchdog triggered");
}

void kick_watchdog()
{
	k_timer_start(&watchdog_timer, K_MINUTES(CONFIG_WATCHDOG_KICK_INTERVAL_MINUTES), K_MINUTES(CONFIG_WATCHDOG_KICK_INTERVAL_MINUTES));
}

RE: NRF7002 DK system shutdown

Håkon Alseth — Wed, 27 Nov 2024 11:53:34 GMT

Hi,

k_timer runs in interrupt context. You should schedule this to main / thread context, for instance using a workqueue.

Kind regards,

Håkon

RE: NRF7002 DK system shutdown

rainbowkenny — Wed, 27 Nov 2024 11:45:55 GMT

Hi,
I'm calling it from a callback function of a watchdog timer. Please see below:

void system_shutdown()
{
	shutdown_wifi();
	k_sleep(K_SECONDS(1));
	sys_poweroff();
}

void timer_system_shutdown(struct k_timer *timer_id)
{
	LOG_ERR("watchdog triggered");
	system_shutdown();
}

K_TIMER_DEFINE(watchdog_timer, timer_system_shutdown, NULL);

void kick_watchdog()
{
	  k_timer_start(&watchdog_timer, K_MINUTES(CONFIG_WATCHDOG_KICK_INTERVAL_MINUTES), K_MINUTES(CONFIG_WATCHDOG_KICK_INTERVAL_MINUTES));
}

RE: NRF7002 DK system shutdown

Håkon Alseth — Wed, 27 Nov 2024 11:39:35 GMT

Hi,

Can you share a log showing the issue?

Where is the shutdown_wifi() function called from? This should not be called from a interrupt.

Kind regards,

Håkon

RE: NRF7002 DK system shutdown

rainbowkenny — Tue, 26 Nov 2024 21:48:03 GMT

Thank you, this is more clearer!
So below is my shutdown sequence for the wifi chip.

It works if I just use net_mgmt(NET_REQUEST_WIFI_CONNECT_STORED, iface, NULL, 0) to connect to the existing wifi.

However, if I'm doing BT-provisioning (copied from the BT-wifi provisioning sample), this routine won't run successfully, it will get stuck at net_if_down(iface). I suspect this is because the wifi stack is still running.

So my question is how do I stop an on-going provisioning service so that I can turn off the wifi chip completely afterwards?

Many thanks!

int shutdown_wifi()
{
	int ret;
  	struct net_if *iface = net_if_get_default();

	if (!net_if_is_admin_up(iface)) {
		return 0;
	}

	if (!net_if_is_up(iface)){
		return 0;
	}
	ret = net_if_down(iface);
	if (ret) {
		LOG_ERR("net_if_down failed: %d", ret);
		return ret;
	}

	LOG_INF("Interface down");

	return 0;
}

RE: NRF7002 DK system shutdown

Håkon Alseth — Tue, 26 Nov 2024 08:25:52 GMT

Hi,

The nRF5340 will continue running code afterwards, and it will require specific code in order to enter SystemOn or SystemOff mode.

The shutdown sample, from the nRF5340 point of view, does not do much, so there it will enter the idle thread with serial logging enabled, giving a floor current of approx. 0.5 mA.

If you disable all bus peripherals, ie. logging and such, it will be in the lower uA range. Entering systemoff will be even lower.

Kind regards,

Håkon

RE: NRF7002 DK system shutdown

rainbowkenny — Mon, 25 Nov 2024 15:04:18 GMT

Thanks for your reply. Are you suggesting that I only need to use net_if_down() if I want to turn off both host and wifi chip (regardless of the logging for now)?

RE: NRF7002 DK system shutdown

Håkon Alseth — Mon, 25 Nov 2024 14:38:27 GMT

Hi,

[quote user=""]

Background:

We're developing wireless application with the NRF5340-NRF7002 chipset, similar to what's on the 7002DK board.
We'd like to put the system to lowest power mode when it's not being used.
I found two samples related to this: nrf/samples/wifi/shutdown and zephyr/samples/boards/nrf/system_off

My questions are:

Which sample shall I base my project on?

[/quote]

To shut down the nRF700x device, please see the sequence given in samples/wifi/shutdown.

This will completely turn off the power to the nRF700x.

[quote user=""]The wifi/shutdown sample page states that "This also demonstrates how to achieve the lowest possible power consumption in the Host SoC (nRF53, nRF52 or nRF91 Series) when Wi-Fi is enabled but not being used." - How is this achieved? I can only see function net_if_down() is used. I assume this will only turn off the nRF7002 wifi chip, but not the host?[/quote]

This is not entirely true, as the logger is enabled. This will cause the host controller to draw approx. 0.5 mA in sleep. I will report this internally as a documentation error.

To get to a lower current consumption, disabling of the serial interface is required (CONFIG_LOG=n and CONFIG_SERIAL=n).

This example will show how to set the nRF5-device into "SystemOff", which should consume <1 uA:

[quote user=""] zephyr/samples/boards/nrf/system_off [/quote]

This is the lowest power mode, and the device can only be awoken from combinatory logic (GPIO/RESET signal for instance).

[quote user=""]The system_off sample uses sys_poweroff() function, will this shut down both nRF5340 and nRF7002 chips? What happens when BT and/or Wifi are being used?[/quote]

This will only shut down the host controller.

The nRF700x must be taken down by implementing the wifi/shutdown/main.c::shutdown_wifi() function.

Kind regards,

Håkon