sd_power_system_off is giving Gatt Connection Error instead of going in sleep

[AIRAM]

I am utilizing the nRF52811 with SDK version 16.00 for a project. However, I have encountered an issue related to the function sd_power_system_off, which is intended to put the device into a sleep mode. Instead of entering sleep mode, the function triggers an error labeled as "GATT_CONN_ERROR" on the nRF Connect mobile application.

I have taken the necessary steps to debug the issue, and through this process, I have confirmed that the sd_power_system_off function is indeed the source of the problem. To resolve this, I have conducted extensive research on various forums, but unfortunately, I have not yet identified a suitable solution to rectify this specific error.

In my pursuit of resolving the problem, I considered the potential influence of debugging on the deep sleep functionality. However, even after disconnecting the debugger and allowing the nRF52811 to run independently, the error persists unchanged.

For contextual clarity, I have provided a segment of the relevant code below, where I am implementing the deep sleep functionality:
Given the current situation, I am seeking assistance to address this issue and enable the intended sleep functionality on the nRF52811. Any insights, guidance, or recommendations that can be provided regarding this matter would be greatly appreciated. Thank you in advance for your help.

static void app_timer_callback(void* p_context)
{
    // Add your desired functionality here
}

static void timer_timeout_handler( void* p_context)
{ret_code_t err_code;

  UNUSED_PARAMETER(p_context);
nrf_timer_event_t event_type;

if(normalmode==false){
    timer_counter += 5000;
  NRF_LOG_DEBUG(" = timer_counter %d .",timer_counter );
  NRF_LOG_INFO(" = timer_counter %d.",timer_counter );
     
 if( timer_counter >= 120000)
   {

    
    NRF_LOG_DEBUG(" done;.");
  NRF_LOG_INFO(" done;.");

      app_timer_stop(m_app_timer);
 NRF_LOG_DEBUG(" cleared.");
  NRF_LOG_INFO(" cleared.");

// Configure the App Timer for the desired time interval (5 minutes)
interval_ms =  300 * 1000;  // 5 minutes
err_code = app_timer_start(m_app_timer, APP_TIMER_TICKS(interval_ms), NULL);
APP_ERROR_CHECK(err_code);
        
    NRF_LOG_DEBUG(" shifted.");
  NRF_LOG_INFO(" shifted.");
 }

    }

    else if (normalmode==true){
    if(f1<0.05 && f2<0.05 && f3<0.05 && f4<0.05){
    ds_counter+=5000;
    if(ds_counter>=5000){

  err_code = app_timer_stop(m_app_timer);
APP_ERROR_CHECK(err_code);
//sleep_mode_enter();
    // Go to system-off mode (this function will not return; wakeup will cause a reset).
    err_code = sd_power_system_off();
     if (err_code != NRF_SUCCESS) {
        NRF_LOG_WARNING("sd_power_system_off() failed, errCode=0x%x\n", err_code);
        return;
    //APP_ERROR_CHECK(err_code);

}}}}}
    

[Jared]

Hi,

First, I would like to point out, that if you put the nRF52811 into system off sleep while it's in a connection, then it's natural to expect the other side of the connection to result in a GATT_CONN_ERROR as the connection will be disrupted. Before you go to sleep, you should send a disconnect event, by disconnecting from the peer. 

Another important point is that nRF52811 will only emulate deep sleep when the debugger is connected, you need to disconnect the debugger for it to actually enter deep sleep.

 

regards

Jared 

[AIRAM]

Hi Jared,
Thank you so much for your time and help.
I have another question or favor to ask. Can you please explain how can I send a disconnect event by disconnecting from peer.

[Jared]

Hi,

You should also add nrf_gpio_cfg_sense_set(),

regards

Jared 

[AIRAM]

Hi, 
I tried adding this but same situation is persisting. Any other suggestions that i can try?

[Jared]

What parameters did you pass to the function? 

For an example on how to use it, see the pwr_mgmt example:

regards

Jared

[AIRAM]

static void sleep_mode_enter(void)
{
  nrf_gpio_cfg_input(18, NRF_GPIO_PIN_PULLUP);
  nrf_gpio_cfg_sense_input(18, NRF_GPIO_PIN_PULLUP, NRF_GPIO_PIN_SENSE_LOW);
  nrf_gpio_cfg_sense_set(18, NRF_GPIO_PIN_SENSE_LOW);


 uint32_t err_code;
    sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);

    while(m_conn_handle != BLE_CONN_HANDLE_INVALID)
    {
       //Poll the application scheduler to execute the main loop 
       //This will ensure that the disconnect event is handled properly by lower levels of the application
 app_sched_execute();

    }

 // Go to system-off mode (this function will not return; wakeup will cause a reset).
   err_code = sd_power_system_off();
    APP_ERROR_CHECK(err_code);

}

[AIRAM]

After it's graceful disconnection, the device can't wakeup so that it doesn't advertise 
When I click on connect tab from last session connection it give an error 133 which tells that device from previous bond is trying to connect but devise is not currently advertising,
Do i need to reinitialize everything like ble stack, softdevice and each and every function?
If so can you please let me how i can do this?

[Jared]

What do you mean? Isn't the issue now that the chip can't wakeup from system off?

After a disconnection, you only need to restart advertising for it to connect again,

regards

Jared 

[AIRAM]

Yes, the issue is chip can't wake up from system off.
How can i restart advertising again
By using this?
advertising_init();

[AIRAM]

If this needs to be added, i tried adding it but same results

[Jared]

If you go to system off then you need to do intialize everything again, if you only disconnect then you can restart advertising by calling 

ble_advertising_start(),

How do you determine that the board doesn't wakeup?

regards

Jared

[AIRAM]

It doesn't advertise on sensing a GPIO low,
Okay i will try re advertising after system off mode