NUS service without service discovery

[Josef80]

Hi.

I have implemented the Central and Peripheral NUS service on two devices(nRF52). Since the central knows the characteristic values, I would like to bypass service discovery to reduce the time connection. I removed the "ble_db_discovery_start" from the BLE_GAP_EVT_CONNECTED and I found the handle values of RX, TX but I don't know how can I store them in my code and how can I use them to read and write the data. I would appreciate it if you kindly help me to overcome this problem.

thanks.

[Susheel Nuguru]

Harry,

It is a generic application logic that you create a stucture that has characteristic UUID and its handle value as two members. For all the characteristic your application knows, save one entry for each of them with the handle value. When you need to write something, you need to search for the appropriate handle value for the given characteristic.

simplest_struct {

 uint16_t char_uuid;
uint16_t  handle_value;
}

The logic of searching through all the available UUIDs to and getting its appropriate handle value should not be hard. I, unfortunately, do not have time to write the actual code

[Josef80]

I solved my problem with the following solution.

void bypass_discovery(ble_nus_c_t * p_ble_nus_c)
{
     ble_nus_c_evt_t nus_c_evt;
     memset(&nus_c_evt,0,sizeof(ble_nus_c_evt_t));

    // the handle values of rx, tx, and ccd may be different in your project.
     nus_c_evt.handles.nus_rx_handle = 16;   
     nus_c_evt.handles.nus_tx_handle = 20;  
     nus_c_evt.handles.nus_tx_cccd_handle = 21;  
     nus_c_evt.conn_handle = conn_hndl;
     nus_c_evt.evt_type = BLE_NUS_C_EVT_DISCOVERY_COMPLETE;
     p_ble_nus_c->evt_handler(p_ble_nus_c, &nus_c_evt);
}

I made the following changes in the BLE_GAP_EVT_CONNECTED case under the ble_evt_handler function.

case BLE_GAP_EVT_CONNECTED:

     // err_code = ble_db_discovery_start(&m_db_disc, p_ble_evt->evt.gap_evt.conn_handle);
     //  APP_ERROR_CHECK(err_code);

        bypass_discovery(&m_ble_nus_c);