Mismatch between connection handles in ble_nus?

RE: Mismatch between connection handles in ble_nus?

Duy — Sat, 21 Mar 2020 07:45:34 GMT

Hello,

I just tested with SDK 15.3 and 16.0 and the problem is still there. The solution still works well.

I added ble_nus_c_evt.conn_handle = p_ble_nus_c->conn_handle; in function on_hvx

**@brief     Function for handling Handle Value Notification received from the SoftDevice.
 *
 * @details   This function will uses the Handle Value Notification received from the SoftDevice
 *            and checks if it is a notification of the NUS TX characteristic from the peer. If
 *            it is, this function will decode the data and send it to the
 *            application.
 *
 * @param[in] p_ble_nus_c Pointer to the NUS Client structure.
 * @param[in] p_ble_evt   Pointer to the BLE event received.
 */
static void on_hvx(ble_nus_c_t * p_ble_nus_c, ble_evt_t const * p_ble_evt)
{
    // HVX can only occur from client sending.
    if (   (p_ble_nus_c->handles.nus_tx_handle != BLE_GATT_HANDLE_INVALID)
        && (p_ble_evt->evt.gattc_evt.params.hvx.handle == p_ble_nus_c->handles.nus_tx_handle)
        && (p_ble_nus_c->evt_handler != NULL))
    {
        ble_nus_c_evt_t ble_nus_c_evt;

        ble_nus_c_evt.evt_type = BLE_NUS_C_EVT_NUS_TX_EVT;
        ble_nus_c_evt.p_data   = (uint8_t *)p_ble_evt->evt.gattc_evt.params.hvx.data;
        ble_nus_c_evt.data_len = p_ble_evt->evt.gattc_evt.params.hvx.len;
        
        /* Modifed here to solve the problem conn_handle update */
        ble_nus_c_evt.conn_handle = p_ble_nus_c->conn_handle;

        p_ble_nus_c->evt_handler(p_ble_nus_c, &ble_nus_c_evt);
        NRF_LOG_DEBUG("Client sending data.");
    }
}

Best regards,

Duy

RE: Mismatch between connection handles in ble_nus?

Sigurd — Mon, 23 Apr 2018 06:55:43 GMT

Hi sara,

It's when you get the BLE_NUS_C_EVT_DISCOVERY_COMPLETE in the function ble_nus_c_evt_handler()

RE: Mismatch between connection handles in ble_nus?

sara — Fri, 20 Apr 2018 09:32:50 GMT

Hello Sigurd,

where should i set "ble_nus_c_handles_assign(..)" function?

All the definition are follow the sample code as you provided.

Thanks.

RE: Mismatch between connection handles in ble_nus?

Kashinath — Fri, 09 Mar 2018 09:36:42 GMT

Hi Sigurd,

Thank you for you reply,

Now that issue solved, now multi connection to central is working, but it is not printing data received from peripheral, means next event is not working, i getting output like this in terminal:

<warning> nrf_sdh_ble: RAM starts at 0x20004190, can be adjusted to 0x20002038.
.<warning> nrf_sdh_ble: RAM size can be adjusted to 0xDFC8.
.<info> app: Multilink example started.
.<info> app: Start scanning for device name Nordic_Blinky.
.<info> app: Connection 0x0 established, starting DB discovery

Please suggest me, i am new to this. thank you in advance

RE: Mismatch between connection handles in ble_nus?

Sigurd — Fri, 09 Mar 2018 09:02:47 GMT

Hi Kashinath,

You are running into the APP_ERROR_CHECK(err_code) on line 217 in main.c. You should check what function returned this err_code(often the function right above the APP_ERROR_CHECK), and why it returned NRF_ERROR_INVALID_STATE. If you have more questions about this, you should create your own question here at Devzone.

RE: Mismatch between connection handles in ble_nus?

Kashinath — Thu, 08 Mar 2018 12:51:52 GMT

Hi Sigurd,

by referring this above, I am using the multilink central example for NUS_C, i changed the code by combining the multilink central and BLE_APP_UART central, i am trying to print the data, but i am not able to print data and also i am getting error after disconnecting all the peripheral.. please suggest me to resolve this issue

I am getting error like this

Nordic_Blinky.
.<info> app: Connection 0x1 established, starting DB discovery.
.<info> app: NUS central link 0x1 disconnected (reason: 0x8)
.<info> app: Start scanning for device name Nordic_Blinky.
.<info> app: Connection 0x1 established, starting DB discovery.
.<info> app: NUS central link 0x1 disconnected (reason: 0x8)
.<info> app: Start scanning for device name Nordic_Blinky.
.<info> app: Connection 0x1 established, starting DB discovery.
.<info> app: NUS central link 0x1 disconnected (reason: 0x8)
.<info> app: Start scanning for device name Nordic_Blinky.
.<info> app: NUS central link 0x0 disconnected (reason: 0x8)
.<info> app: Start scanning for device name Nordic_Blinky.
.<error> app: ERROR 8 [NRF_ERROR_INVALID_STATE] at D:\Printer_software\New Folder\nRF5_SDK_14.2.0_17b948a\nRF5_SDK_14.2.0_17b948a\examples\ble_central\ble_app_multilink_central -working\main.c:217

RE: Mismatch between connection handles in ble_nus?

Boaz — Sun, 08 Jan 2017 10:40:57 GMT

Thanks Sigurd, that is basically the code I ended up with.

RE: Mismatch between connection handles in ble_nus?

Sigurd — Fri, 06 Jan 2017 15:26:38 GMT

Hi,

Yes, the on_hvx() is not setting the conn_handle for the BLE_NUS_C_EVT_NUS_RX_EVT event, but you have access to the conn_handle in the p_ble_nus_c struct. Ideally it should also be set for the ble_nus_c_evt, i.e. ble_nus_c_evt.conn_handle = p_ble_nus_c->conn_handle; in on_hvx().

When the nus_c service was initially designed, the nRF5 series only had support for one connection. Later the code was refactored and ble_nus_c_handles_assign() was added so we can keep track of what connection belongs to what instance of NUS.

So if the overall goal is to use the nus_c service in multiple connections, I recommend that you create a separate NUS and DB structure instance for each connection:

static ble_nus_c_t              m_ble_nus_c[TOTAL_LINK_COUNT];
static uint8_t                  m_ble_nus_c_count;  
static ble_db_discovery_t       m_ble_db_discovery[TOTAL_LINK_COUNT];

Then each instance of NUS would have to be assigned a connection handle with ble_nus_c_handles_assign() when you get the event BLE_NUS_C_EVT_DISCOVERY_COMPLETE. In nus_c_init() and db_discovery_init() you will need to initialize each instance. In nus_c_init() this could look something like this:

static void nus_c_init(void)
{
    uint32_t         err_code;
    ble_nus_c_init_t nus_c_init_t;

    nus_c_init_t.evt_handler = ble_nus_c_evt_handler;
    
	for (m_ble_nus_c_count = 0; m_ble_nus_c_count < TOTAL_LINK_COUNT; m_ble_nus_c_count++)
    {
        err_code = ble_nus_c_init(&m_ble_nus_c[m_ble_nus_c_count], &nus_c_init_t);
        APP_ERROR_CHECK(err_code);
    }
    m_ble_nus_c_count = 0;
}

The db_disc_handler() function would look something like this:

static void db_disc_handler(ble_db_discovery_evt_t * p_evt)
{
    ble_nus_c_on_db_disc_evt(&m_ble_nus_c[p_evt->conn_handle], p_evt);
}

In ble_evt_dispatch(), ble_db_discovery_on_ble_evt() and ble_nus_c_on_ble_evt() should be changed to something like this:

uint16_t conn_handle;
conn_handle = p_ble_evt->evt.gap_evt.conn_handle;

ble_db_discovery_on_ble_evt(&m_ble_db_discovery[conn_handle], p_ble_evt);
ble_nus_c_on_ble_evt(&m_ble_nus_c[conn_handle],p_ble_evt);

You should also take a look at the multilink central example in the SDK to see how this example handles multiple connections.