BLE with SPI doesn´t reconnect once bluetooth has been disabled and enabled again.

[dolrairom]

I'm currently working with nrf52832 implementing bluetooth and spi functionalities. The bluetooth connection to PC is working fine, it connects and after that starts transfering and receiving data from SPI slave. The problem comes once I decide to turn bluetooth off on the PC. It connects and disconnects constantly. It also happens once I turn off/on the power button on the SDK.

Here it is the main code and the spi configuration:

int main(void)
{
    bool erase_bonds;


    ret_code_t err_code;

    spi_configuration();

    APP_ERROR_CHECK(nrf_drv_clock_init());
    nrf_drv_clock_lfclk_request(NULL);
    
    log_init();
    

    err_code = app_timer_init();
    APP_ERROR_CHECK(err_code);


    motion_timer_init();

 
    // Initialize.
    buttons_leds_init(&erase_bonds);
    power_management_init();
    ble_stack_init();
    scheduler_init();
    gap_params_init();
    gatt_init();
    advertising_init();
    services_init();
    conn_params_init();
    peer_manager_init();
    bsp_board_init(BSP_INIT_LEDS);

    // Start execution.
    advertising_start(erase_bonds);

    // Enter main loop.
    for (;;)
    {
      if(connected){
        NRF_LOG_INFO("Connected.");

        laser_frame();  //transfer and receive spi data
       
      }

      idle_state_handle();
      nrf_delay_ms(2000);
    }
}


void spi_configuration(void){
  /* SPI Configuration */
    nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
    spi_config.ss_pin   = SPI_SS_PIN;
    spi_config.miso_pin = SPI_MISO_PIN;
    spi_config.mosi_pin = SPI_MOSI_PIN;
    spi_config.sck_pin  = SPI_SCK_PIN;

    APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, spi_event_handler, NULL));

}

If spi_configuration() and laser_frame() are commented, the problem when reconnecting disappears. Any idea? Thanks!

[Kenneth]

That nrf_delay_ms(2000); looked scary. 

Can you try to allow re-pairing by adding the following in pm_evt_handler() in main.c

case PM_EVT_CONN_SEC_CONFIG_REQ:
{
// Allow or reject pairing request from an already bonded peer.
pm_conn_sec_config_t conn_sec_config = {.allow_repairing = true};
pm_conn_sec_config_reply(p_evt->conn_handle, &conn_sec_config);
} break;

[dolrairom]

Hey, sorry for the late reply. I have been trying what you propossed and a few more things and this is what I get:

1. (nrf_delay_ms(2000); deleted) After adding your code I realized that it never goes into that case so it keeps disconnecting and connecting when attempting to reconnect. Still getting error 4102.
2.  I though it could be because it deletes the bonds in the line 37 so I changed it with advertising_start(false);
3. Now the sequence I get is:

<info> app:     m_whitelist_peer_cnt 2, MAX_PEERS_WLIST 8
<info> app: Fast advertising with whitelist.
<info> app: Connected
<info> app: Connected.

(gets one data buffer from spi slave)

<error> app: Fatal error
<warning> app: System reset

Also I keep getting the following (3 times in a row) while BLE configuration but it connects after all:

<error> nrf_ble_gatt: sd_ble_gatts_exchange_mtu_reply() returned NRF_ERROR_INVALID_STATE.

[Hung Bui]

Hi, 

Please follow the debug guide here. 

We need to know what function threw the error code . 

sd_ble_gatts_exchange_mtu_reply() should not be called when not in connection. 

Which example did you base your code on ? 

[dolrairom]

Hi Hung Bui!

Hung Bui said:

Please follow the debug guide here

This guide seems to be for Keil users but I'm using SES, is there any other guide for this software?

Hung Bui said:

sd_ble_gatts_exchange_mtu_reply() should not be called when not in connection.

This error appear after connection, I attach a snip where it's shown.

Hung Bui said:

Which example did you base your code on ?

I'm using both BLE_app_hids_mouse and spi examples.

[Hung Bui]

It doesn't really matter if you use KEIL or SES the fundamental is the same, you set a breakpoint in the assert handler and find which line causes which error code. Make sure you turn off optimization and add DEBUG into the preprocessor symbols. 

Note that the MTU reply should only be called inside the BLE_GATTS_EVT_EXCHANGE_MTU_REQUEST event handler. 

[awneil]

Hung Bui said:

It doesn't really matter if you use KEIL or SES the fundamental is the same

Indeed.

But here's an article on debugging with SES:

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fug_gsg_ses%2FUG%2Fgsg%2Fdebug.html

See also the SES documentation.

And articles on Monitor Mode Debug:

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fug_gsg_ses%2FUG%2Fgsg%2Fdebug.html

And debugging in general:

https://www.avrfreaks.net/comment/2418156#comment-2418156

[Hung Bui]

Thanks Andrew :) 

[dolrairom]

Hi, thank you for both replies Andrew and Hung Bui. I set debug mode and was able to find the error. It said something about error in soft device so finally I found out that it was trying to send mouse movement through bluetooth before having a stable connection. I defined a flag for connection and now it's working perfect. Thanks!