ATT error code 0x06 (BT_ATT_ERR_NOT_SUPPORTED) when I try to write to a server characteristic

[Andrea Verdecchia]

I'm working on a inertial sensor (peripheral/server) which shoiuld communicate througth BLE with a custom USB dongle (central/client). Both systems mount the nRF52840 and I developing the firmware in VS Code with NRF Connect SDK 2.3.0.

Now when I connect the sensor to the nRf Connect application on my phone all seems to be ok: I can write on my custom characteristic and I can enable notify for my two custom characteristic as well. So I can confirm that the sensor works fine for now.

But If I connect the sensor to my custom dongle, I can't forward the USB commands to the BLE because when I write to my characteristic I get the BT_ATT_ERR_NOT_SUPPORTED. For the dongle I used the central_uart example that uses the NUS client. I modified it creating my own sensor client. The code of my dongle is the following (only the BLE) and the starting point is the Ble_Connection_Initialize function at the bottom. Whats the problem?

#include "ble_connection.h"


/*******************************************************************************
 *  Global Variables
 ******************************************************************************/
static bt_addr_le_t deviceAddr;
static struct bt_conn_cb bluetootCallbacks;
static struct bt_conn *currentConnection;
static struct bt_uuid_128 uuid = BT_UUID_INIT_128( 0 );
static struct bt_gatt_discover_params discoverParams;
static struct bt_gatt_subscribe_params subscribeParams;
static bool deviceConnected;
static gravity_client_t gravityClient;
static K_THREAD_STACK_DEFINE( bleSendDataStackArea, BLE_CONNECTION_SEND_DATA_THREAD_STACKSIZE );
static struct k_thread bleSendDataThreadData;
static k_tid_t bleSendDataThreadId;
K_SEM_DEFINE( bleWriteSemaphore, 0, 1 );
K_FIFO_DEFINE( fifoBleTxData );
K_FIFO_DEFINE( fifoBleRxData );
K_FIFO_DEFINE( fifoBleRxInertialData );


/*******************************************************************************
 *  Function Definitions
 ******************************************************************************/
static void Discovery_Gatt( struct bt_conn *conn );
static void Discovery_Complete( struct bt_gatt_dm *dm, void *context );
static void Discovery_Service_Not_Found( struct bt_conn *conn, void *context );
static void Discovery_Error( struct bt_conn *conn, int err, void *context );
static void Ble_Connection_Mtu_Exchange( struct bt_conn *conn, uint8_t err, struct bt_gatt_exchange_params *params );
static void Ble_Connection_On_Connect( struct bt_conn *conn, uint8_t err );
static void Ble_Connection_On_Disconnect( struct bt_conn *conn, uint8_t reason );
static void Ble_Connection_Security_Changed( struct bt_conn *conn, bt_security_t level, enum bt_security_err err );
static void Ble_Connection_Message_Tx_Sent( gravity_client_t *client, uint8_t err, const uint8_t *const data, uint16_t len );
static uint8_t Ble_Connection_Message_Rx_Notify_Func( gravity_client_t *client, const uint8_t *data, uint16_t len );
static uint8_t Ble_Connection_Inertial_Rx_Notify_Func( gravity_client_t *client, const uint8_t *data, uint16_t len );
static void Ble_Connection_Scan_Filter_Match( struct bt_scan_device_info *device_info, struct bt_scan_filter_match *filter_match, bool connectable );
static void Ble_Connection_Scan_Connecting_Error( struct bt_scan_device_info *device_info );
static void Ble_Connection_Scan_Connecting( struct bt_scan_device_info *device_info, struct bt_conn *conn );
static system_error_t Ble_Connection_Scan_Initialize( void );
static system_error_t Ble_Connection_Start_Scan( void );
static void Ble_Connection_Auth_Cancel( struct bt_conn *conn );
static void Ble_Connection_Pairing_Complete( struct bt_conn *conn, bool bonded );
static void Ble_Connection_Pairing_Failed( struct bt_conn *conn, enum bt_security_err reason );
static system_error_t Ble_Connection_Gravity_Client_Initialize( void );
static void Ble_Connection_Send_Data_Thread( void );

struct bt_gatt_dm_cb discoveryCb = {
	.completed         = Discovery_Complete,
	.service_not_found = Discovery_Service_Not_Found,
	.error_found       = Discovery_Error,
};

BT_SCAN_CB_INIT( scanCb, Ble_Connection_Scan_Filter_Match, NULL, Ble_Connection_Scan_Connecting_Error, Ble_Connection_Scan_Connecting );

static struct bt_conn_auth_cb connAuthCallbacks = {
	.cancel = Ble_Connection_Auth_Cancel,
};

static struct bt_conn_auth_info_cb connAuthInfoCallbacks = {
	.pairing_complete = Ble_Connection_Pairing_Complete,
	.pairing_failed = Ble_Connection_Pairing_Failed
};


/*******************************************************************************
 *  Function:
 * 
 *      static void Discovery_Gatt( struct bt_conn *conn )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static void Discovery_Gatt( struct bt_conn *conn )
{
	if ( conn != currentConnection )
    {
		return;
	}

	if ( bt_gatt_dm_start( conn, BT_UUID_GRAVITY_SERV, &discoveryCb, &gravityClient ) != 0 )
    {
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Could not start the discovery procedure" );
	}
}


/*******************************************************************************
 *  Function:
 * 
 *      static void Discovery_Complete( struct bt_gatt_dm *dm, void *context )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static void Discovery_Complete( struct bt_gatt_dm *dm, void *context )
{
    struct bt_gravity_client *client = context;

	SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_INFO, "\n[I] Service discovery completed" );
	bt_gatt_dm_data_print( dm );
	Gravity_Client_Handles_Assign( dm, client );
	Gravity_Client_Subscribe_Receive( client );
	bt_gatt_dm_data_release( dm );
}


/*******************************************************************************
 *  Function:
 * 
 *      static void Discovery_Service_Not_Found( struct bt_conn *conn, uint8_t err )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static void Discovery_Service_Not_Found( struct bt_conn *conn, void *context )
{
	SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Service not found" );
}


/*******************************************************************************
 *  Function:
 * 
 *      static void Discovery_Error( struct bt_conn *conn, int err, void *context )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static void Discovery_Error( struct bt_conn *conn, int err, void *context )
{
	SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Error while discovering GATT database: %d", err );
}


/*******************************************************************************
 *  Function:
 * 
 *      static void Ble_Connection_Mtu_Exchange( struct bt_conn *conn, uint8_t err, struct bt_gatt_exchange_params *params )
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static void Ble_Connection_Mtu_Exchange( struct bt_conn *conn, uint8_t err, struct bt_gatt_exchange_params *params )
{
	if ( !err ) 
    {
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_INFO, "\n[I] MTU exchange done" );
	} 
    else 
    {
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] MTU exchange failed (err %" PRIu8 ")", err );
	}

    // Discovery_Gatt( conn );
}


/*******************************************************************************
 *  Function:
 * 
 *      static void Ble_Connection_On_Connect( struct bt_conn *conn, uint8_t err )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static void Ble_Connection_On_Connect( struct bt_conn *conn, uint8_t connErr )
{
    char addr[ BT_ADDR_LE_STR_LEN ];
    int err;
    static struct bt_gatt_exchange_params exchangeParams;

    bt_addr_le_to_str( bt_conn_get_dst( conn ), addr, sizeof( addr ) );

    if ( connErr )
    {
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Failed to connect to %s ( %u )", addr, connErr );
        bt_conn_unref( currentConnection );
		currentConnection = NULL;
		Ble_Connection_Start_Scan();
        App_Change_State( APP_STATE_ERROR );
        return;
    }

    SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_INFO, "\n[I] Connected to %s", addr );
    deviceConnected = true;
    App_Change_State( APP_STATE_CONNECTED );
	exchangeParams.func = Ble_Connection_Mtu_Exchange;
	
    if ( bt_gatt_exchange_mtu( conn, &exchangeParams ) != 0 )
    {
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] MTU exchange failed" );
        // Discovery_Gatt( conn );
	}

    if ( bt_conn_set_security( conn, BT_SECURITY_L2 ) != 0 )
    {
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Failed to set security" );
		Discovery_Gatt( conn );
	}

    err = bt_scan_stop();

	if ( ( !err ) && ( err != -EALREADY ) )
    {
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Stop LE scan failed (err %d)", err );
	}
}


/*******************************************************************************
 *  Function:
 * 
 *      static void Ble_Connection_On_Disconnect( struct bt_conn *conn, uint8_t reason )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static void Ble_Connection_On_Disconnect( struct bt_conn *conn, uint8_t reason )
{
    char addr[ BT_ADDR_LE_STR_LEN ];

    if ( currentConnection == conn )
    {
        bt_addr_le_to_str( bt_conn_get_dst( conn ), addr, sizeof( addr ) );
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_INFO, "\n[I] Disconnected: %s ( reason 0x%02x )", addr, reason );
        deviceConnected = false;
        App_Change_State( APP_STATE_IDLE );
        bt_conn_unref( currentConnection );
        currentConnection = NULL;
        Ble_Connection_Start_Scan();
    }
}


/*******************************************************************************
 *  Function:
 * 
 *      static void Ble_Connection_Security_Changed( struct bt_conn *conn, bt_security_t level, enum bt_security_err err )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static void Ble_Connection_Security_Changed( struct bt_conn *conn, bt_security_t level, enum bt_security_err err )
{
	char addr[ BT_ADDR_LE_STR_LEN ];

	bt_addr_le_to_str( bt_conn_get_dst( conn ), addr, sizeof( addr ) );

	if ( !err )
    {
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_INFO, "\n[I] Security changed: %s level %u", addr, level );
	}
    else
    {
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Security failed: %s level %u err %d", addr, level, err );
	}

	Discovery_Gatt( conn );
}


/*******************************************************************************
 *  Function:
 * 
 *      static void Ble_Connection_Message_Tx_Sent( gravity_client_t *client, uint8_t err, const uint8_t *const data, uint16_t len )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static void Ble_Connection_Message_Tx_Sent( gravity_client_t *client, uint8_t err, const uint8_t *const data, uint16_t len )
{
	ARG_UNUSED( client );

	k_sem_give( &bleWriteSemaphore );

	if ( err )
    {
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] ATT error code: 0x%02X", err );
	}
}


/*******************************************************************************
 *  Function:
 * 
 *      static uint8_t Ble_Connection_Message_Rx_Notify_Func( gravity_client_t *client, const uint8_t *data, uint16_t len )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static uint8_t Ble_Connection_Message_Rx_Notify_Func( gravity_client_t *client, const uint8_t *data, uint16_t len )
{
    ARG_UNUSED( client );
    SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_INFO, "%s", data );
	return BT_GATT_ITER_CONTINUE;
}


/*******************************************************************************
 *  Function:
 * 
 *      static uint8_t Ble_Connection_Inertial_Rx_Notify_Func( gravity_client_t *client, const uint8_t *data, uint16_t len )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static uint8_t Ble_Connection_Inertial_Rx_Notify_Func( gravity_client_t *client, const uint8_t *data, uint16_t len )
{
    ARG_UNUSED( client );
    Usb_Connection_Send_Inertial_Data( ( char * )data, len );
	return BT_GATT_ITER_CONTINUE;
}


/*******************************************************************************
 *  Function:
 * 
 *      static void Ble_Connection_Scan_Filter_Match( struct bt_scan_device_info *device_info, struct bt_scan_filter_match *filter_match, bool connectable )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static void Ble_Connection_Scan_Filter_Match( struct bt_scan_device_info *device_info, struct bt_scan_filter_match *filter_match, bool connectable )
{
	char addr[ BT_ADDR_LE_STR_LEN ];

	bt_addr_le_to_str( device_info->recv_info->addr, addr, sizeof( addr ) );
    SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_INFO, "\n[I] Filters matched. Address: %s connectable: %d", addr, connectable );
}


/*******************************************************************************
 *  Function:
 * 
 *      static void Ble_Connection_Scan_Connecting_Error( struct bt_scan_device_info *device_info )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static void Ble_Connection_Scan_Connecting_Error( struct bt_scan_device_info *device_info )
{
    SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Connecting failed" );
}


/*******************************************************************************
 *  Function:
 * 
 *      static void Ble_Connection_Scan_Connecting( struct bt_scan_device_info *device_info, struct bt_conn *conn )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static void Ble_Connection_Scan_Connecting( struct bt_scan_device_info *device_info, struct bt_conn *conn )
{
	currentConnection = bt_conn_ref( conn );
}


/*******************************************************************************
 *  Function:
 * 
 *      static system_error_t Ble_Connection_Start_Scan( void )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static system_error_t Ble_Connection_Scan_Initialize( void )
{
    struct bt_scan_init_param scanInit = {
		.connect_if_match = 1,
	};

	bt_scan_init( &scanInit );
	bt_scan_cb_register( &scanCb );

	if ( bt_scan_filter_add( BT_SCAN_FILTER_TYPE_UUID, BT_UUID_GRAVITY_SERV ) != 0 )
    {
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Scanning filters cannot be set" );
		return SYSTEM_ERROR;
	}

	if ( bt_scan_filter_enable( BT_SCAN_UUID_FILTER, false ) != 0 )
    {
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Filters cannot be turned on" );
		return SYSTEM_ERROR;
	}

    SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_INFO, "\n[I] Scan module initialized" );
	return SYSTEM_NO_ERROR;
}


/*******************************************************************************
 *  Function:
 * 
 *      static system_error_t Ble_Connection_Start_Scan( void )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static system_error_t Ble_Connection_Start_Scan( void )
{
    if ( bt_scan_start( BT_SCAN_TYPE_SCAN_ACTIVE ) != 0 )
    {
		return SYSTEM_ERROR;
	}

    return SYSTEM_NO_ERROR;
}


/*******************************************************************************
 *  Function:
 * 
 *      static void Ble_Connection_Auth_Cancel( struct bt_conn *conn )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static void Ble_Connection_Auth_Cancel( struct bt_conn *conn )
{
	char addr[ BT_ADDR_LE_STR_LEN ];

	bt_addr_le_to_str( bt_conn_get_dst( conn ), addr, sizeof( addr ) );
    SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_INFO, "\n[I] Pairing cancelled: %s", addr );
}


/*******************************************************************************
 *  Function:
 * 
 *      static void Ble_Connection_Pairing_Complete( struct bt_conn *conn, bool bonded )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static void Ble_Connection_Pairing_Complete( struct bt_conn *conn, bool bonded )
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
    SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_INFO, "\n[I] Pairing completed: %s, bonded: %d", addr, bonded );
}


/*******************************************************************************
 *  Function:
 * 
 *      static void Ble_Connection_Pairing_Failed( struct bt_conn *conn, enum bt_security_err reason )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static void Ble_Connection_Pairing_Failed( struct bt_conn *conn, enum bt_security_err reason )
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
    SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Pairing failed conn: %s, reason %d", addr, reason );
}


/*******************************************************************************
 *  Function:
 * 
 *      static system_error_t Ble_Connection_Gravity_Client_Initialize( void )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static system_error_t Ble_Connection_Gravity_Client_Initialize( void )
{
    gravity_client_init_param_t init = {
		.cb = {
            .sent = Ble_Connection_Message_Tx_Sent,
			.messageReceived = Ble_Connection_Message_Rx_Notify_Func,
            .messageUnsubscribed = NULL,
            .inertialReceived = Ble_Connection_Inertial_Rx_Notify_Func,
            .inertialUnsubscribed = NULL,
		}
	};

	if ( Gravity_Client_Initialize( &gravityClient, &init ) != SYSTEM_NO_ERROR )
    {
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Gravity client initialization failed" );
		return SYSTEM_ERROR;
	}

    SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_INFO, "\n[I] Gravity client module initialized" );
    return SYSTEM_NO_ERROR;
}


/*******************************************************************************
 *  Function:
 * 
 *      static void Ble_Connection_Send_Data_Thread( void )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
static void Ble_Connection_Send_Data_Thread( void )
{
    ble_tx_data_t *txBuf;

    for ( ;; )
	{
        txBuf = k_fifo_get( &fifoBleTxData, K_FOREVER );

        if ( Gravity_Client_Send_Data( &gravityClient, txBuf->data, txBuf->len ) != SYSTEM_NO_ERROR )
        {
            SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Failed to send data over BLE connection" );
        }

		if ( k_sem_take( &bleWriteSemaphore, K_MSEC( 150 ) ) != 0 )
        {
            SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Send data timeout" );
		}
	}
}


/*******************************************************************************
 *  Function:
 * 
 *      system_error_t Ble_Connection_Initialize( void )
 *
 *  Description:
 * 
 *      None.
 * 
 *  Parameters: 
 * 
 *      None.
 * 
 *  Returns:
 * 
 *      None.
 *   
 ******************************************************************************/
system_error_t Ble_Connection_Initialize( void )
{
    deviceConnected = false;
    bluetootCallbacks.connected = Ble_Connection_On_Connect;
    bluetootCallbacks.disconnected = Ble_Connection_On_Disconnect;
    bluetootCallbacks.security_changed = Ble_Connection_Security_Changed;
    bt_conn_cb_register( &bluetootCallbacks );
    bt_addr_le_from_str( BT_GRAVITY_DEVICE_ADDR, BT_GRAVITY_DEVICE_TYPE, &deviceAddr );    

    if ( bt_conn_auth_cb_register( &connAuthCallbacks ) != 0 ) 
    {
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Failed to register authorization callbacks" );
        System_Dbg_Err_Type_Set( SYSTEM_ERROR_INIT_BLE_CONNECTION );
		return SYSTEM_ERROR;
	}

	if ( bt_conn_auth_info_cb_register( &connAuthInfoCallbacks ) != 0 )
    {
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Failed to register authorization info callbacks" );
        System_Dbg_Err_Type_Set( SYSTEM_ERROR_INIT_BLE_CONNECTION );
		return SYSTEM_ERROR;
	}

    if ( bt_enable( NULL ) != 0 )
    {
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Bluetooth init failed" );
        System_Dbg_Err_Type_Set( SYSTEM_ERROR_INIT_BLE_CONNECTION );
		return SYSTEM_ERROR;
	}

    SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_INFO, "\n[I] Bluetooth initialized" );

    if ( Ble_Connection_Scan_Initialize() != SYSTEM_NO_ERROR )
    {
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Bluetooth scan initialize failed" );
        System_Dbg_Err_Type_Set( SYSTEM_ERROR_INIT_BLE_CONNECTION );
		return SYSTEM_ERROR;
    }

    if ( Ble_Connection_Gravity_Client_Initialize() != SYSTEM_NO_ERROR )
    {
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Bluetooth gravity client initialize failed" );
        System_Dbg_Err_Type_Set( SYSTEM_ERROR_INIT_BLE_CONNECTION );
		return SYSTEM_ERROR;
    }

    if ( Ble_Connection_Start_Scan() != SYSTEM_NO_ERROR )
    {
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Bluetooth scan start failed" );
        System_Dbg_Err_Type_Set( SYSTEM_ERROR_INIT_BLE_CONNECTION );
		return SYSTEM_ERROR;
    }

    bleSendDataThreadId = NULL;
    bleSendDataThreadId = k_thread_create( &bleSendDataThreadData,
											bleSendDataStackArea,
											K_THREAD_STACK_SIZEOF( bleSendDataStackArea ),
											Ble_Connection_Send_Data_Thread,
											NULL,
											NULL,
											NULL,
											BLE_CONNECTION_SEND_DATA_THREAD_PRIORITY,
											0,
											K_NO_WAIT);

	if ( bleSendDataThreadId == NULL )
	{
        SYSTEM_DBG_PRINT( SYSTEM_DBG_LEVEL_WARNING, "\n[W] Creating Ble_Connection_Send_Data_Thread failed" );
		System_Dbg_Err_Type_Set( SYSTEM_ERROR_INIT_STATUS_LED );
		return SYSTEM_ERROR;
	}

    return SYSTEM_NO_ERROR;
}

[Andrea Verdecchia]

I forgot to say that the dongle, when the bt_conn_set_security function is called, its callback returns the BT_SECURITY_ERR_PAIR_NOT_SUPPORTED error and then it connects to the sensor and give me the BT_ATT_ERR_NOT_SUPPORTED when I write.

[Sigurd Hellesvik]

Hi,

Now when I connect the sensor to the nRf Connect application on my phone all seems to be ok: I can write on my custom characteristic and I can enable notify for my two custom characteristic as well. So I can confirm that the sensor works fine for now.

Is this using a Developement Kit or a Dongle?

But If I connect the sensor to my custom dongle,

Does our out-of-the-box bluetooth samples work with your custom board?

Have you created custom board files for your custom board?

Regards,
Sigurd Hellesvik

[Andrea Verdecchia]

Sigurd Hellesvik said:

Is this using a Developement Kit or a Dongle?

The sensor (peripheral role) is a custom board and you can see the whole project here.

The dongle (central role) is a nRF52840DK and you can see the whole project here.

You can find the BT code in the ble_connection.* (also gravity_client.* for the dongle).

I repeat: the BT_ATT_ERR_NOT_SUPPORTED error is given by the dongle (central role). The sensor seems to work fine since if I connect to it via nRf Connect on my phone I can send and receive.

[Andrea Verdecchia]

I found the issue. I was using the bt_gatt_write function to send the data but the chattacteristic of the sensor is configuread as BT_GATT_CHRC_WRITE_WITHOUT_RESP: So I have to use the bt_gatt_write_without_response_cb finction instead. Thanks anyway.