Reset on_ble_connect when button event

[DanKA]

Hello,

my problem is reproducable with this Setup:

• nRF5-DK with ble_blinky_example (central)
• nRF5-DK with ble_blinky_example (peripheral)
• Press Button1 immediately on the peripheral after connecting (LED2 lights up).
• watch how the peripheral goes back to Advertising (resets)
• Press Button1 after the Connection is established a while, everything works fine.

 When the button_event_handler() is empty, the devices stay connected. What causes this and how to avoid it?

Kind regards,

DanKA

[DanKA]

When i use a single shot timer to wait a couple milliseconds before i call app_button_enable(), there is no reset:

in on_ble_evt():

        case BLE_GAP_EVT_CONNECTED:
                NRF_LOG_INFO("Connected\r\n");
                err_code = app_timer_stop(m_adv_con_led_timer_id);
                APP_ERROR_CHECK(err_code);
                //bsp_board_led_on(CONNECTED_LED_PIN);
                m_conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
                err_code = app_timer_start(m_off_timer_id, APP_TIMER_TICKS(400, APP_TIMER_PRESCALER), NULL);
                APP_ERROR_CHECK(err_code);
                break; // BLE_GAP_EVT_CONNECTED

and then the timer_handler

                uint8_t  err_code = app_button_enable();
                APP_ERROR_CHECK(err_code);
                bsp_board_led_on(CONNECTED_LED_PIN);

[Susheel Nuguru]

which SDK version are you testing this on? And which softdevice version you have on the board?

[DanKA]

Hello Aryan, 

i use SDK 12.3 and Softdevice S130 2.0.1/ Softdevice S132 3.0.0. I attached a video.

• Peripheral left, central right.
• First: in connection, everything fine. (Button press is indicated with a led).
• Second: Switch off and on the peripheral, same with resetting  via IF BOOT/RESET. Press Button1 directly after connecting (LED2 lights up). Board goes back to advertising.
• Third: Wait after connection. Everything works fine. (Button press is indicated with a led).

[Susheel Nuguru]

I think the problem is with the below code

static void button_event_handler(uint8_t pin_no, uint8_t button_action)
{
    uint32_t err_code;

    switch (pin_no)
    {
        case LEDBUTTON_BUTTON_PIN:
            NRF_LOG_INFO("Send button state change.\r\n");            
            err_code = ble_lbs_on_button_change(&m_lbs, button_action);
            if (err_code != NRF_SUCCESS &&
                err_code != BLE_ERROR_INVALID_CONN_HANDLE &&
                err_code != NRF_ERROR_INVALID_STATE)
            {
                APP_ERROR_CHECK(err_code);
            }
            break;

        default:
            APP_ERROR_HANDLER(pin_no);
            break;
    }
}

 

You can clearly see here that we are trying to send a notification here without checking if the device is connected or not. In your case, when you press the button before the device is connected, then the ble_lbs_on_button_change would return error and you will hit the APP_ERROR_CHECK which by default will reset your device.

The best would be to change the function to below

static void button_event_handler(uint8_t pin_no, uint8_t button_action)
{
    uint32_t err_code;

    switch (pin_no)
    {
        case LEDBUTTON_BUTTON_PIN:
            NRF_LOG_INFO("Send button state change.\r\n");
        if(m_conn_handle != BLE_CONN_HANDLE_INVALID)        
        {
            err_code = ble_lbs_on_button_change(&m_lbs, button_action);
            if (err_code != NRF_SUCCESS &&
                err_code != BLE_ERROR_INVALID_CONN_HANDLE &&
                err_code != NRF_ERROR_INVALID_STATE)
            {
                APP_ERROR_CHECK(err_code);
            }
            break;

        default:
            APP_ERROR_HANDLER(pin_no);
            break;
        }
    }
}

now we will attempt to send notifications only if there is a connection.

[DanKA]

I am very sorry to reject the answer that late. The suggested solution does not work - it is still the same behaviour as shown in the Video. I did test it with the timer metioned in the first answer active and thought i would work.

However, in my application, i want to show that the device is in a Connection so that the customer can start interacting. So, when the LED lights up, i want to be sure that there is a Connection.

Aryan's answer wants to check that, but as i said: the device resets if there is a button release immediately after Connection. The timer i used is not an elegant solution because just it delays enabling the app_button and the ligthing up the LED.

Any suggestions are very much appreciated.  

Reproducable with nRR5-DK, SDK 12.3 and Softdevice S130 2.0.1/ Softdevice S132 3.0.0 using the ble_app_blinky example.

Kind regards

DanKa

[Susheel Nuguru]

Hi Dan,

It is quite easy to debug set a breakpoint at the app_error_handler and see which line caused this error.

The answer I gave you in my last post is a fix for one bug we saw. And I realized it within few minutes of setting the breakpoint at everyplace in project that has NVIC_SystemReset();

Please start your project in debug mode and see why the call stack when you see that your breakpoint is hit.