Sleep does not work with BLE advertise

[silvio3105]

Hi,

nRF52832, SDK 17.1.0 with Softdevice S132.

Softdevice sleep does not work when advertising. Application flow is to advertise one packet, then go to sleep for X seconds. Sleep part waits for a flag from "BLE_GAP_EVT_ADV_SET_TERMINATED" event.

If "sd_app_evt_wait" is replaced with "__WFI" when sleep works but BLE does not advertise anymore(even BLE_GAP_EVT_ADV_SET_TERMINATED is received).

Any idea how to put device to sleep?

This code works

	//BLE::advertise(&data, sizeof(data));

	while (1)
	{
		/*if (System::isWoken() == Return_t::OK)
		{
			BLE::advertise(&data, sizeof(data));
		}*/

		//if (BLE::isAdvertiseDone() == Return_t::OK)
		if (1)
		{
			System::startWakeupTimer();
			System::sleep();
		}

		// Feed the dog
		System::feedWatchdog();
	}

This code does not work(consumption around ~3.5mA)

	BLE::advertise(&data, sizeof(data));

	while (1)
	{
		if (System::isWoken() == Return_t::OK)
		{
			BLE::advertise(&data, sizeof(data));
		}

		if (BLE::isAdvertiseDone() == Return_t::OK)
		//if (1)
		{
			System::startWakeupTimer();
			System::sleep();
		}

		// Feed the dog
		System::feedWatchdog();
	}

sleep function:

	void sleep(void)
	{
		__set_FPSCR(__get_FPSCR()  & ~(0x0000009F));      
		(void) __get_FPSCR();
		sd_nvic_ClearPendingIRQ(FPU_IRQn);		

		sd_power_dcdc_mode_set(NRF_POWER_DCDC_DISABLE);

		_PRINT("Sleep\n");
		sd_app_evt_wait();

		sd_power_dcdc_mode_set(NRF_POWER_DCDC_ENABLE);
	}

Only RTC2 IRQ is enabled. FPU is disabled(soft FPU is used).

System init

	Return_t init(void)
	{
		// Test crystals only in debug build
		#ifdef DEBUG
		_PRINT("Wait for HFXO\n");
		NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;
		NRF_CLOCK->TASKS_HFCLKSTART = 1;
		while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0);
		NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;	
		_PRINT("HFXO started\n");

		_PRINT("Wait for LFXO\n");
		NRF_CLOCK->EVENTS_LFCLKSTARTED = 0;
		NRF_CLOCK->TASKS_LFCLKSTART = 1;
		while (NRF_CLOCK->EVENTS_LFCLKSTARTED == 0);
		NRF_CLOCK->EVENTS_LFCLKSTARTED = 0;	
		_PRINT("LFXO started\n");		
		#endif // DEBUG

		// Configure power
		NRF_POWER->POFCON = 0;
		NRF_POWER->DCDCEN = 1;

		// Init watchdog
		NRF_WDT->CRV = (AppConfig::wdtTimeout * 32768) - 1;
		#ifdef DEBUG
		NRF_WDT->CONFIG = 1;
		#else
		NRF_WDT->CONFIG = 9;
		#endif // DEBUG
		NRF_WDT->TASKS_START = 1;

		// Enable RTC interrupt
		ret_code_t ret = sd_nvic_SetPriority(RTC2_IRQn, 2);
		if (ret != NRF_SUCCESS)
		{
			APP_ERROR_CHECK(ret);
			return Return_t::NOK;
		}

		ret = sd_nvic_EnableIRQ(RTC2_IRQn);
		if (ret != NRF_SUCCESS)
		{
			APP_ERROR_CHECK(ret);
			return Return_t::NOK;
		}

		// Enable compare0 interrupt
		NRF_RTC2->INTENSET = (1 << 16);

		// Set counter resolution of 125ms
		NRF_RTC2->PRESCALER = 4095;

		startWakeupTimer();
		return Return_t::OK;
	}
	
	void startWakeupTimer(void)
	{
		NRF_RTC2->TASKS_CLEAR = 1;
		NRF_RTC2->CC[0] = (AppConfig::measurePeriod * 1000) / 125;
		NRF_RTC2->TASKS_START = 1;
		_PRINT_INFO("Wakeup timer started\n");
	}

EDIT: BLE init functions

	Return_t init(void)
	{
		ret_code_t ret;

		ret = nrf_sdh_enable_request();
		if (ret != NRF_SUCCESS)
		{
			APP_ERROR_CHECK(ret);
			return Return_t::NOK;
		}
	
		// Configure the BLE stack using the default settings.
		uint32_t ramStart = 0;
		ret = nrf_sdh_ble_default_cfg_set(AppConfig::bleTag, &ramStart);
		if (ret != NRF_SUCCESS)
		{
			APP_ERROR_CHECK(ret);
			return Return_t::NOK;
		}
	
		// Enable BLE stack.
		ret = nrf_sdh_ble_enable(&ramStart);
		if (ret != NRF_SUCCESS)
		{
			APP_ERROR_CHECK(ret);
			return Return_t::NOK;
		}
	
		// Register a handler for BLE events.
		NRF_SDH_BLE_OBSERVER(m_ble_observer, 3, onBLEEvent, NULL);

		// Init GAP profile
		if (gapInit() != Return_t::OK)
		{
			return Return_t::NOK;
		}	

		// Get MAC address
		ble_gap_addr_t addr;
		ret = sd_ble_gap_addr_get(&addr);
		if (ret != NRF_SUCCESS)
		{
			APP_ERROR_CHECK(ret);
			return Return_t::NOK;
		}		
		_PRINTF_INFO("MAC: %02X%02X%02X%02X%02X%02X\n", addr.addr[5], addr.addr[4], addr.addr[3], addr.addr[2], addr.addr[1], addr.addr[0]);

		// Request HFXO
		ret = sd_clock_hfclk_request();
		if (ret != NRF_SUCCESS)
		{
			APP_ERROR_CHECK(ret);
			return Return_t::NOK;
		}		

		// Init advertise
		return advInit();
	}

	/**
	 * @brief Advertise data.
	 * 
	 * @return \c Return_t::NOK on fail.
	 * @return \c Return_t::OK on success.
	 */
	Return_t advertise(const void* data, const uint8_t len)
	{
		// Set custom data
		ble_advdata_manuf_data_t mnfData;
		
		mnfData.company_identifier = AppConfig::bleMnfID;
		mnfData.data.p_data = (uint8_t*)data;
		mnfData.data.size = len;
	
		// Set advertise data
		ble_advdata_t advData;
		memset(&advData, 0, sizeof(advData));
		advData.name_type = BLE_ADVDATA_FULL_NAME;
		advData.flags = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;
		advData.p_manuf_specific_data = &mnfData;
		advData.p_tx_power_level = &txPower;
	
		// Encode advertise data
		ret_code_t ret = ble_advdata_encode(&advData, gapAdvData.adv_data.p_data, &gapAdvData.adv_data.len);
		if (ret != NRF_SUCCESS)
		{	
			APP_ERROR_CHECK(ret);
			return Return_t::NOK;
		}

		// Advertise data
		advDone = 0;
		ret = sd_ble_gap_adv_start(advHandle, AppConfig::bleTag);
		if (ret != NRF_SUCCESS)
		{
			APP_ERROR_CHECK(ret);
			return Return_t::NOK;
		}		

		return Return_t::OK;
	}
	
/**
 * @brief Init BLE GAP profile.
 * 
 * @return \c Return_t::NOK on fail.
 * @return \c Return_t::OK on success.
 */
static Return_t gapInit(void)
{
	ble_gap_conn_sec_mode_t securtiyMode;
	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&securtiyMode);

	ret_code_t ret = sd_ble_gap_device_name_set(&securtiyMode, (const uint8_t*)AppConfig::deviceName, __CONST_STR_LEN(AppConfig::deviceName));
	if (ret != NRF_SUCCESS)
	{
		APP_ERROR_CHECK(ret);
		return Return_t::NOK;
	}

	return Return_t::OK;
}

/**
 * @brief Init BLE advertise.
 * 
 * @return \c Return_t::NOK on fail.
 * @return \c Return_t::OK on success. 
 */
static Return_t advInit(void)
{
	// Set advertise config
	advConfig.primary_phy = BLE_GAP_PHY_AUTO;
	advConfig.duration = 0;
	advConfig.properties.type = BLE_GAP_ADV_TYPE_NONCONNECTABLE_SCANNABLE_UNDIRECTED;
	advConfig.max_adv_evts	= AppConfig::advCount;
	advConfig.p_peer_addr = nullptr;
	advConfig.filter_policy = BLE_GAP_ADV_FP_ANY;
	advConfig.interval = 32; // Does not matter since max advertise event is set to 1 

	ret_code_t ret = sd_ble_gap_adv_set_configure(&advHandle, &gapAdvData, &advConfig);
	if (ret != NRF_SUCCESS)
	{	
		APP_ERROR_CHECK(ret);
		return Return_t::NOK;
	}

	// Set TX power
	ret = sd_ble_gap_tx_power_set(BLE_GAP_TX_POWER_ROLE_ADV, advHandle, txPower);
	if (ret != NRF_SUCCESS)
	{	
		APP_ERROR_CHECK(ret);
		return Return_t::NOK;
	}		

	return Return_t::OK;
}

[Einar Thorsrud]

Hi,

When using a SoftDevice you should wait by calling sd_app_evt_wait(), and not WFI (or WFE for that matter) directly. Advertising in itself should not cause any probem, should not contribute to current consumption in between advertising events. Can you show the implementation of your BLE::advertise(), as it is including that that increases the current consumption?

[silvio3105]

Hi,

BLE functions are added to main post.

Seems like device does not go to sleep since I can connect to it via SWD(J-Link). I guess some BLE event prevents sleep.
I tried __WFI just for test otherwise SD sleep function is used.

[silvio3105]

Does DEBUG flag or LOG module has effect on wakeups?
This is power consumption without DEBUG flag and NRF LOG module. Softdevice is disabled before calling __WFI();
It looks the same as consumption without DEBUG and LOG module and SD is not disabled before calling SD sleep function.

[Einar Thorsrud]

silvio3105 said:

Does DEBUG flag or LOG module has effect on wakeups?

No. If you don't use deferred logging, logs will be processed whenever there is logging. If you use deferred logging, you process logs in your main loop before calling sd_app_evt_wait() (as you can see in most SDK examples).

silvio3105 said:

This is power consumption without DEBUG flag and NRF LOG module. Softdevice is disabled before calling __WFI();
It looks the same as consumption without DEBUG and LOG module and SD is not disabled before calling SD sleep function.

sd_app_evt_wait() will only make the CPU sleep, it does not do anythign else to put the system in a low power mode (like stopping peripherals etc). If you use UART for logging(?) for instance, that will increase power consumption as the UART will stay on also in sleeep.

If you could zoom in the time scale so we see the actual current consumption pattern of just the peak, with some luck, we may be able to recognize what it could be. Also, are you using a DK or a custom board, and is the DCDC enabled or not? And if not using a DK, what is the supply voltage? (this could help in understanding what wee see in a zoomed in current consumption plot). Perhaps you can also export and update the data from the power analyser so that I can zoom in and look at this on my end?

silvio3105 said:

Is there any way to disable LF calibration from Softdevice?

Calibration is only used when the LFRC is enabled. It is not possible (nor needed) to calibrate the LFXO, so this should not be relevant as you write that. you have configured LFXO.

silvio3105 said:

Softdevice is used only for advertise. I don't know why I have double peaks and why MCU is woken up when measure/advertise period is 5 seconds.

As mentionned, we need to look more closely at the peaks to know what they could represent. And the next is to look at your code. As you use LFXO, the SoftDevice will only wake up for BLE events.

[silvio3105]

I use RTT for logging. Only RTC2 is enabled during sleep. ADC is stopped and disabled on EVENTS_END.

VDD is 3V from PPK2. Only PPK2 is connected, no J-Link.
RTC2 wakeup period(and advertise period) is 5s.

When you say BLE events - what do you mean by BLE events? I use only BLE for advertise. Scanner and connect stuff should be disabled, so no BLE events for that?

I use custom board

DCDC is disabled before sleep and enabled after wakeup(due to higher consumption with DCDC on during sleep).

Code is: https://github.com/silvio3105/sTPMS_FW/tree/dev (dev branch, application and modules folder)

ppk2-20250325T110356.ppk2

This is done with DEBUG build(DEBUG flag is added during build, NRF_LOG is enabled over RTT)
Most os these peaks are 2.5s apart. nRF connect app says period is 5 seconds.

[silvio3105]

I think is not HW problem.

I did this

main()
{

NRF_POWER->POFCON = 0;

NRF_POWER->DCDCEN = 1;

while ()

{

__WFI();

}

// OLD CODE

}

And consumption is ~7uA

[silvio3105]

So I reduced base power consumption when in sleep to ~5uA. Only problem is that I have peaks(BLE/SD?) every 2.5 seconds. Wakeup period is 5s.

Closer look to 2.5s peaks

EDIT:

Seems like RTC2 is cause of wakeup. Not sure why since I don't see anything related to CC / 2 wakeup/interrupt/event.

EDIT2: Errata for rev2 - section 3.47

[Einar Thorsrud]

Hi,

I see, so you are triggering errata 179 from your use?

The zoomed in is still a bit fare out, but it could look like the first is BLE advertising (though it is still ab it dificult to see clearly, so you could export and upload the .ppk2 file). But other than that, we would probably  need to look in your code to understand what any other wakups are, as the SoftDevice will not wake the device unless it has work to do (which it will not have outside of BLE events when you use a 32.768 kHz crytsal).

[silvio3105]

Code is at

github.com/.../Main.cpp
https://github.com/silvio3105/sTPMS_FW/tree/dev/Modules

I did a test - did not used RTC2 and its wakeup(just commented RTC stuff) and let watchdog do the reset. It had peaks every 9 seconds(WDT period is measure period + 4 seconds). At that time, softdevice was enabled and BLE is used for advertise(1 adv event) right after startup and before sleep.

Is there any way to use softdevice for wakeup with periods up to 60 seconds?

[Einar Thorsrud]

silvio3105 said:

Is there any way to use softdevice for wakeup with periods up to 60 seconds?

The SoftDevice it self will wake the CPU (based on RTC0) when needed, but it will put the CPU to sleep again without fordarding to the application unless there are events for the application. For the application to wake on a specific ime, you need to use your own RTC instances (either like you do with RTC2, or for instance using the app_timer library which is based on RTC1.

[silvio3105]

Did you find anything in the code? I use RTC2 and as we see, it causes some problems with peaks every cc/2.

[Einar Thorsrud]

No, I would like to get the .ppk2 files first to see if the pattern looks familliar