How to disable radio notification after enabling it

RE: How to disable radio notification after enabling it

Øyvind Karlsen — Tue, 21 Jun 2016 11:06:24 GMT

This was with S132 using SDK 11, what version of SD110, SD130 and SDK are you using? The current draw is due to the chip not being able to sleep, likely due to a pending interrupt.

RE: How to disable radio notification after enabling it

Øyvind Karlsen — Tue, 21 Jun 2016 10:27:25 GMT

Hi,

Firstly NRF_RADIO_SIGNAL_CALLBACK_ACTION_END ends the ongoing timeslot, but not the timeslot session (timeslot events occur in the context of a timeslot session, please refer to the SoftDevice Specification), this means that you will not get an NRF_EVT_SESSION_CLOSED. If you at some point call sd_radio_session_close() you must call sd_radio_session_open(handler) again to be able to open a timeslot event.

I am not able to reproduce your issue, I have modified a version of the ble_app_template example to use radio notification and timeslots. Please refer to my code below. In order to see correct current draw I made sure to sleep by calling

__SEV();
__WFE();
__WFE();

Instead of sd_app_evt_wait();. Please see this thread. I measured the current using a N6705B DC Power Analyzer.

I set a flag using GPIO to enable/disable radio notifications on the next timeslot, which I also trigger by GPIO. I've also made some simplifications to the example given in the answer above

int main(void)
{
    uint32_t err_code;
    bool erase_bonds;

    // Initialize.
    timers_init();
    buttons_leds_init(&erase_bonds);
    ble_stack_init();
    device_manager_init(erase_bonds);
    gap_params_init();
    advertising_init();
    services_init();
    conn_params_init();
    
    enable_radio_notification = false; // Set Radio Notification enable flag to false
    err_code = sd_radio_notification_cfg_set(NRF_RADIO_NOTIFICATION_TYPE_INT_ON_ACTIVE, NRF_RADIO_NOTIFICATION_DISTANCE_800US);   //Configure only once
    APP_ERROR_CHECK(err_code);
        
    application_timers_start();
    
    err_code = ble_advertising_start(BLE_ADV_MODE_FAST); // Start execution.
    APP_ERROR_CHECK(err_code);
    
    err_code = sd_radio_session_open(timeslot_callback); // Create timeslot session
    APP_ERROR_CHECK(err_code);
    
    // Enter main loop.
    for (;;)
    {
        __SEV();
        __WFE();
        __WFE();
    }
}


nrf_radio_signal_callback_return_param_t * timeslot_callback(uint8_t signal_type)
{
    static nrf_radio_signal_callback_return_param_t signal_callback_return_param;

    switch(signal_type)
    {
      case NRF_RADIO_CALLBACK_SIGNAL_TYPE_START:
         signal_callback_return_param.params.request.p_next = NULL;           // End timeslot
         signal_callback_return_param.callback_action = NRF_RADIO_SIGNAL_CALLBACK_ACTION_END;

            
         nrf_gpio_pin_toggle(20); // For signal analyzer verification
        
         if(enable_radio_notification)                                                                                                               //Boolean flag to enable/disable radio notification
         {
             NVIC_ClearPendingIRQ(SWI1_IRQn);
             NVIC_EnableIRQ(SWI1_IRQn);
         } 
         else 
         {
             NVIC_ClearPendingIRQ(SWI1_IRQn);
             NVIC_DisableIRQ(SWI1_IRQn);
         }
            
         nrf_gpio_pin_toggle(20);
         break;

       default:
         break;
    }    
    return (&signal_callback_return_param);
}

Please find attached in the main answer a folder containing images of the different current test cases. Note that the 800µA draw is due to the application not being power optimized, HFCLK is running, etc.

RE: How to disable radio notification after enabling it

Arjun — Tue, 21 Jun 2016 09:11:14 GMT

Øyvind, We are using Ampere meter method for measurement. That is sufficient for us to observe the problem. In order to observe with more accuracy one can increase advertising interval or decrease scan window. In the slave example(where the bug is) we can easily see the current falling to uA range even with simple multimeter on bootup. But after a connection-disconnection sequence it does not.

RE: How to disable radio notification after enabling it

Øyvind Karlsen — Tue, 21 Jun 2016 07:00:07 GMT

There are several methods in that tutorial, which one are you using and what equipment?

RE: How to disable radio notification after enabling it

Arjun — Mon, 20 Jun 2016 13:39:40 GMT

We are using measurement procedure as described in this tutorial -> devzone.nordicsemi.com/.../. In order to observe current consumption variations we change advertising interval/ scan window.

RE: How to disable radio notification after enabling it

Øyvind Karlsen — Mon, 20 Jun 2016 13:30:36 GMT

Still working on this.

Could you elaborate more about your current measurement setup?

RE: How to disable radio notification after enabling it

FormerMember — Fri, 17 Jun 2016 15:47:42 GMT

Thanks for looking into this Øyvind. The reason that we need radio notifications is that it is the only way that we found to sync accurately with the connection events. We tried using a timer, but it drifts over time with respect to the connection event.

We tried your solution. case NRF_RADIO_CALLBACK_SIGNAL_TYPE_TIMER0: is called after the SWI0 handler as expected. But after this NRF_EVT_RADIO_SESSION_CLOSED is not received. Also when the next time a timeslot is tried to be opened, it always returns NRF_ERROR_BUSY. Somehow signal_callback_return_param.callback_action = NRF_RADIO_SIGNAL_CALLBACK_ACTION_END; doesn't seem to close the timeslot.

Why are you particular about closing the timeslot this way? There is sd_radio_session_close() API which can be used? Using this generates the NRF_EVT_RADIO_SESSION_CLOSED and next time the timeslot can be opened, but we're facing increased current consumption as mentioned.

I've attached the radio_notif.c file that we are using in the question. Is your solution working for repeated use in your setup?

RE: How to disable radio notification after enabling it

Øyvind Karlsen — Fri, 17 Jun 2016 12:43:07 GMT

As stated in the answer below, if you initialize or deinitialize(essentially the same function) when you have a possibility of collision with SoftDevice activity you can/will run into problems.

RE: How to disable radio notification after enabling it

Øyvind Karlsen — Fri, 17 Jun 2016 12:41:13 GMT

Hi,

Starting with a general answer for further reference:

If you have set up radio notifications and do not want to use it, clear the interrupt right after receiving it, this will cause CPU to wakeup once and add some extra current, but is a easy and low complexity solution. If you need to do something periodically there are better, simpler and more energy efficient solutions than using radio notifications. For instance you can use the application timer as described in this tutorial.

To disable radio notifications you have a few options, some fit certain solutions better than others. To ensure proper operation we need to heed the following sentence from the SoftDevice specification.

To ensure that the Radio Notification signals behave in a consistent way, the Radio Notification 
shall always be configured when the SoftDevice is in an idle state with no protocol stack or 
other SoftDevice activity in progress. Therefore, it is recommended to configure the Radio 
Notification signals directly after the SoftDevice has been enabled.

Start off by making sure that the first time it is initialized is in a section where the SoftDevice is not active, for example right after initialization.

In the right context, radio notification can be disabled by calling:

// Deinitialize Radio Notification software interrupt
uint32_t ble_radio_notification_uninit(void)
{
    err_code = sd_nvic_ClearPendingIRQ(SWI1_IRQn);
    if (err_code != NRF_SUCCESS)
    {
        return err_code;
    }
    err_code = sd_nvic_DisableIRQ(SWI1_IRQn);
    if (err_code != NRF_SUCCESS)
    {
        return err_code;
    }
    return sd_radio_notification_cfg_set(NRF_RADIO_NOTIFICATION_TYPE_NONE, NRF_RADIO_NOTIFICATION_DISTANCE_NONE);
}

This context limitations is the same as for the first initialization of the radio notifications, as described above. We need to find some context where there will not be any SoftDevice activity. Since we already have radio notifications set up it is simplest to call ble_radio_notification_uninit() inside itself. However if we want to restart it we will be faced with the problem of when/how to restart it.

One of the tools available is a radio timeslot where radio activity is guaranteed to not occur. When using timeslots be aware that you cannot call SoftDevice functions in the signal handler as it executes at priority 0. A simple timeslot signal handler that fulfills our purpose is:

nrf_radio_signal_callback_return_param_t * timeslot_callback(uint8_t signal_type)
{
  static nrf_radio_signal_callback_return_param_t signal_callback_return_param;

  switch(signal_type)
  {
      case NRF_RADIO_CALLBACK_SIGNAL_TYPE_START:
	  
         signal_callback_return_param.params.request.p_next = NULL;
         signal_callback_return_param.callback_action = NRF_RADIO_SIGNAL_CALLBACK_ACTION_NONE;

         NRF_TIMER0->INTENSET = TIMER_INTENSET_COMPARE0_Msk;                  // Timeslot timeout bookkeeper
         NRF_TIMER0->CC[0] = m_slot_length - 1000;
         NVIC_EnableIRQ(TIMER0_IRQn);

         NVIC_EnableIRQ(SWI0_IRQn);                                           // Set artififical interrupt
         NVIC_SetPendingIRQ(SWI0_IRQn);

         break;
    
     case NRF_RADIO_CALLBACK_SIGNAL_TYPE_TIMER0:
     
         signal_callback_return_param.params.request.p_next = NULL;           // End timeslot
         signal_callback_return_param.callback_action = NRF_RADIO_SIGNAL_CALLBACK_ACTION_END;

	default:
	      break;
  }    
  return (&signal_callback_return_param);
}

And the corresponding IRQ handler:

void SWI0_IRQHandler(void){
	//Context where we can call SoftDevice functions
	uint32_t err_code = sd_nvic_ClearPendingIRQ(SWI0_IRQn);																						//Clear artifical IRQ
	APP_ERROR_CHECK(err_code);
	err_code = sd_nvic_DisableIRQ(SWI0_IRQn);																									//Disable artificial IRQ channel
	APP_ERROR_CHECK(err_code);

	if(enable_radio_notification)																												//Boolean flag to enable/disable radio notification
	{
		err_code = sd_nvic_ClearPendingIRQ(SWI1_IRQn);
		APP_ERROR_CHECK(err_code);
		err_code = sd_nvic_EnableIRQ(SWI1_IRQn);
		APP_ERROR_CHECK(err_code);
		err_code = sd_radio_notification_cfg_set(NRF_RADIO_NOTIFICATION_TYPE_YOURTYPEHERE, NRF_RADIO_NOTIFICATION_DISTANCE_YOURDISTANCEHERE);	//Set desired type and distance
		APP_ERROR_CHECK(err_code);
	} 
	else 
	{
		err_code = sd_nvic_ClearPendingIRQ(SWI1_IRQn);
		APP_ERROR_CHECK(err_code);
		err_code = sd_nvic_DisableIRQ(SWI1_IRQn);
		APP_ERROR_CHECK(err_code);
		err_code = sd_radio_notification_cfg_set(
		NRF_RADIO_NOTIFICATION_TYPE_NONE, NRF_RADIO_NOTIFICATION_DISTANCE_NONE);
		APP_ERROR_CHECK(err_code);
	}
	sd_nvic_SetPendingIRQ(TIMER0_IRQn);               					//Trigger the timer interrupt to end the timeslot
}

To reiterate, this is a very complicated way of solving a relatively simple problem, make sure that you are absolutely sure that this is the way you want to solve the problem if you go down this road.

Best regards,

Øyvind

EDIT:

Current draw measurements

RE: How to disable radio notification after enabling it

Arjun — Thu, 16 Jun 2016 15:03:27 GMT

Great! Thanks

RE: How to disable radio notification after enabling it

Øyvind Karlsen — Thu, 16 Jun 2016 13:43:53 GMT

I am still looking into this, will get back to you with a reply tomorrow.

RE: How to disable radio notification after enabling it

Arjun — Wed, 15 Jun 2016 11:36:13 GMT

Hi Karlsen, Any update regarding the issue? Were you able to reproduce what I was talking about?

RE: How to disable radio notification after enabling it

Øyvind Karlsen — Tue, 14 Jun 2016 12:12:16 GMT

You are right, that was a blunder on my part

RE: How to disable radio notification after enabling it

FormerMember — Tue, 14 Jun 2016 11:41:48 GMT

Hi Øyvind, Isn't the timeslot_callback called in priority 0 meaning that sd_*** calls can't be made there?

RE: How to disable radio notification after enabling it

Øyvind Karlsen — Tue, 14 Jun 2016 11:21:02 GMT

Hi,

EDIT: I was wrong, will investigate some more.

I will update the tutorials on radio notifications and timeslots later this week to the latest SDK/SD and attempt to improve clarity, feedback is very welcome.

RE: How to disable radio notification after enabling it

Arjun — Tue, 14 Jun 2016 09:33:18 GMT

Hi Karlsen,

I certainly have. Also you can see the example I have attached with the question. That should run on DK and you can observe the problem for slave device.

RE: How to disable radio notification after enabling it

Øyvind Karlsen — Tue, 14 Jun 2016 09:30:22 GMT

Hi Arjun,

Have you tried disabling the IRQ by calling

err_code = sd_nvic_Disable_IRQ(SW1_IRQn);
APP_ERROR_CHECK(err_code);

Øyvind

RE: How to disable radio notification after enabling it

Arjun — Thu, 09 Jun 2016 14:21:26 GMT

Hi Anders,

Please find the code you asked for. It shud run on DK. The bug appears for advertising device only. But if we get to know the issue i think we can use the same logic for our actual implementations.

RE: How to disable radio notification after enabling it

Arjun — Wed, 08 Jun 2016 15:31:24 GMT

We are using custom boards.Since I cannot share the code Ill make a bare minimum version of software for DK, reproduce the bug and send the example to you as soon as possible. Again thanks for timely responses.

RE: How to disable radio notification after enabling it

Anders Strand — Wed, 08 Jun 2016 14:57:23 GMT

I see. Is the code running on a Dev Kit? If it does, i can try to run your code and see if i can figure something out

RE: How to disable radio notification after enabling it

Arjun — Tue, 07 Jun 2016 14:33:32 GMT

Scenario1: After bootup the device enters scanning(radio notification not enabled) the current varies between 11mA to few uA(microamps). My scan window is 500ms with interval of 1 second. Note:If I decrease this scan window (say 10ms) much further then i can observe the device current vary from as low as 2uA to 11mA much easily)

Scenario2: After bootup the device enters scanning and finds the peripheral and establishes connection (radio notification enabled). In connection state it draws a current ~4mA(7.5ms conn interval). Now I switch off the peripheral to trigger disconnection.The master goes back to scanning(disabling the radio notification). This time the current varies between 3mA to 12mA. I cannot observe the device falling to uA current range. Note: If I don`t enable the radio notification in connected mode, then the scanning mode power consumption is as expected. That is how I know that its the problem with enabling notification.

I make sure after programming the devices i hard reset them to disable debug mode.

RE: How to disable radio notification after enabling it

Anders Strand — Tue, 07 Jun 2016 14:09:02 GMT

3mA can indicate that the chip is in debug mode. Do you see this only after the disconnect? Can you describe the current draw during initial advertising, during connection, and after DC?

RE: How to disable radio notification after enabling it

Arjun — Tue, 07 Jun 2016 11:48:59 GMT

Hey Anders,

That was my first guess too.. I tried with clearing pending interrupt. But that did not solve the issue. And regarding current, It has constant base current of ~3mA, and goes higher during advertising and CPU tasks

RE: How to disable radio notification after enabling it

Anders Strand — Tue, 07 Jun 2016 10:58:37 GMT

Hi. How much current are you using after disconnect? The first thing i would check is if the SWI1_IRQn is pending. This would stop you from sleeping. Check the interrupt flag with a a debugger or add

err_code = sd_nvic_ClearPendingIRQ(SWI1_IRQn);
APP_ERROR_CHECK(err_code);

to the disable function.