BLE NUS CENTRAL not ready for comms after receiving BLE_NUS_C_EVT_DISCOVERY_COMPLETE

[veletron]

Hi

I have a modified version of the BLE_NUS Central sample which connects to my production board for production test purposes.

All works fine, and Rx and Tx comms passed to/from the UART to the RX and Tx characteristics of the custom service running on my peripheral.

My issue is that after the central gets BLE_NUS_C_EVT_DISCOVERY_COMPLETE, if I immediately try to perform a GATT_Write on the peripherals RX characteristic, the Central Hangs

 ble_gattc_write_params_t const write_params =
    {
        .write_op = BLE_GATT_OP_WRITE_CMD,
        .flags    = BLE_GATT_EXEC_WRITE_FLAG_PREPARED_WRITE,
        .handle   = p_ble_nus_c->handles.nus_rx_handle,
        .offset   = 0,
        .len      = length,
        .p_value  = p_string
    };

    return sd_ble_gattc_write(p_ble_nus_c->conn_handle, &write_params);

If I run the exact same code a fraction of a second later, it succeeds.

After connection and discovery of my service (and after setting up Notify for the RX and TX characteristics), I need to inform my peripheral who it was that just connected - in this case 'ProductionTestBoard' 0x07. I do this via a protocol structure I use everywhere else in the product.

My question is, can I test wait for any other event, or test the softdevice to wait until it REALLY HAS connected to my peripheral? I tried the usual 'sleep' before the gattc_write to no avail.

Nigel

[Jimmy Wong]

HI,

I guess that you have multiple GATT client at your central role.

You can refer to the code ble_nus_c.c which I modified to use the tx_buffer_process to queue up the write request.

https://github.com/jimmywong2003/nrf5-packet-error-rate-measurement-on-ble-connection/blob/master/sdk_mod/ble_nus_c/ble_nus_c.c