BLE_NUS_C_EVT_NUS_TX_EVT has handle of 0xffff

[syc776]

I have following problem:

I am using a multilink NUS Central. With one peripheral connection everything works fine. But when make a second connection I sometimes get an error when I try to send data back in received event.

In ble_nus_c_evt_handler event with event type BLE_NUS_C_EVT_NUS_TX_EVT the p_ble_nus_c sometimes has an invalid connection handle (0xFFFF).

If I try to send data back I get following warning: <warning> ble_nus_c: Connection handle invalid.

How is this possible? I am assigning the handles with  ble_nus_c_handles_assign on discovery complete.

Does anyone know about this issue?

[awneil]

syc776 said:

I am assigning the handles

Surely, the SoftDevice assigns the handle, and advises it in the 'Connected' event ?

[syc776]

yes I am assigning the handles with  ble_nus_c_handles_assign on discovery complete

void ble_nus_c_on_ble_evt(ble_evt_t const * p_ble_evt, void * p_context)
{
    ble_nus_c_t * p_ble_nus_c = (ble_nus_c_t *)p_context;

    if ((p_ble_nus_c == NULL) || (p_ble_evt == NULL))
    {
        return;
    }

    if ( (p_ble_nus_c->conn_handle != BLE_CONN_HANDLE_INVALID)
       &&(p_ble_nus_c->conn_handle != p_ble_evt->evt.gap_evt.conn_handle)
       )
    {
        return;
    }

    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GATTC_EVT_HVX:
						
            on_hvx(p_ble_nus_c, p_ble_evt);
            break;

        case BLE_GAP_EVT_DISCONNECTED:
            if (p_ble_evt->evt.gap_evt.conn_handle == p_ble_nus_c->conn_handle
                    && p_ble_nus_c->evt_handler != NULL)
            {
                ble_nus_c_evt_t nus_c_evt;

                nus_c_evt.evt_type = BLE_NUS_C_EVT_DISCONNECTED;

                p_ble_nus_c->conn_handle = BLE_CONN_HANDLE_INVALID;
                p_ble_nus_c->evt_handler(p_ble_nus_c, &nus_c_evt);
            }
            break;

        default:
            // No implementation needed.
            break;
    }
}

p_ble_evt->evt.gap_evt.conn_handle=0xffff

[Edvin]

Did you try to implement something similar as in the previous snippet? You need to look for the place that forwards the BLE_NUS_C_EVT_NUS_TX_EVT, and add the connection handle in this event.

look in ble_nus_c.c, and search for BLE_NUS_C_EVT_NUS_TX_EVT. 

Add this line:

ble_nus_c_evt.conn_handle = p_ble_evt->evt.gattc_evt.conn_handle;

before:

p_ble_nus_c->evt_handler(p_ble_nus_c, &ble_nus_c_evt);

[syc776]

yes i do but also like before

[Edvin]

Please check out this ticket with a similar question. I attached a project in this ticket that works in SDK15.2.0. If you need to use SDK15.0.0, then you must do some debugging.

Can you please set a breakpoint in on_hvx() in the ble_nus_c.c file? What is the  conn_handle if you check:

ble_nus_c_evt.conn_handle = p_ble_evt->evt.gattc_evt.conn_handle; ?

NB: gattc_evt, not gap_evt, which I wrote in an earlier answer (corrected now).

Best regards,

Edvin

[syc776]

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;
			
				ble_nus_c_evt.conn_handle = p_ble_evt->evt.gattc_evt.conn_handle;
			
			
        p_ble_nus_c->evt_handler(p_ble_nus_c, &ble_nus_c_evt);
        NRF_LOG_DEBUG("Client sending data.");
    }
}

i have modify the code but it do not work! 

[Edvin]

Edvin said:

Can you please set a breakpoint in on_hvx() in the ble_nus_c.c file? What is the  conn_handle if you check:

ble_nus_c_evt.conn_handle = p_ble_evt->evt.gattc_evt.conn_handle; ?

[syc776]

program is return here

[Edvin]

hehe. Which one?

[syc776]

if ( (p_ble_nus_c->conn_handle != BLE_CONN_HANDLE_INVALID)
&&(p_ble_nus_c->conn_handle != p_ble_evt->evt.gap_evt.conn_handle)
)
{
return;
}

[Edvin]

ok. and which one is false? I assume, based on the topic of this ticket that it is the p_ble_nus_c->conn_handle which is BLE_CONN_HANDLE_INVALID.

Did you check the conn_handle in the function on_hvx() as I suggested?

EDIT:

Sorry. Both return true, of course. '&&'.

But what is the conn_handle in on_hvx() in ble_nus_c.c?

[syc776]

the program can not reach on_hvx()