nRF5340 power consumption on bt_le_adv_stop()

Question

Hi Nordic Semi 
 I have implemented a basic BLE peripheral on a nRF5340 using the nRF Connect SDK 1.7.0.0. 
 The product we are developing have strict power consumption requirements. 
 I thus want to limit the BLE advertising period and upon expiration only allow bonded devices to connect. 
 The advertise expiration, I have implemented by means of a timer ( K_TIMER_DEFINE(..) ). 
 Upon expiration of this timer I call bt_le_adv_stop() . 
 During advertisement I see a power use in the range of 4 mA. 
 When I call bt_le_adv_stop() the power use increate to 7 mA. 
 I can limit this to 5.5. mA, by calling pm_power_state_force((struct pm_state_info){PM_STATE_SUSPEND_TO_IDLE,0,0}) ; But the power use remains higher that while advertising. 
 Can you assist me in normalizing the power use after calling bt_le_adv_stop() ? 
 Regards Tonny

helsing · Accepted Answer

Hi Tonny, great to hear you figured it out.

TBing · Answer

Hi H&aring;kon 
 I found the answer. 
 bt_le_adv_stop() cannot be called from a k_timer handler that executes in timer irq context. 
 The Zephyr documentation states: Use a timer to initiate an asynchronous operation .. 
 A bit fluffy, but it gave a hint. 
 The solution was (as also specified in the documentation) to dispatch the timeout to a Worker Queue, and 
 have a handler call bt_le_adv_stop() from its worker context. 
 static void onAdvertiseTimeoutIrq(struct k_timer *timer)
{
	k_work_submit(&advertiseTimeoutWork);
}

static void onAdvertiseTimeoutWork(struct k_work *work)
{
	bt_le_adv_stop();
}

nRF5340 power consumption on bt_le_adv_stop()

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