How to access the Device Name Characteristic

Question

I was trying around some experiments with the Sdk 5.1 Hrs Example code.
I want to do something special (e.g. turn on a led on the nRF6100 board) when the devicename was changed by a ble central to a specific value. 
 For that, I think I have to hook into ble_evt_dispatch() and must check the parameter p_ble_evt against anything, right? E.g. 
 static void ble_evt_dispatch(ble_evt_t * p_ble_evt) {
 ble_bondmngr_on_ble_evt(p_ble_evt);
 ble_hrs_on_ble_evt(&m_hrs, p_ble_evt);
 ble_bas_on_ble_evt(&m_bas, p_ble_evt);
 ble_conn_params_on_ble_evt(p_ble_evt);
 on_ble_evt(p_ble_evt);
 { // Joe: My own experimental code starts here
 ble_gatts_evt_write_t* p_evt_write = 
 &p_ble_evt->evt.gatts_evt.params.write;
 // 3 = device name handle
 // TODO JM: is there a better way?
 if (p_evt_write->handle == 3) {
 // TODO: How to access the Device Name?
 if (strcmp("?!?", "LED") == 0) { 
 nrf_gpio_cfg_output(LED_4);
 nrf_gpio_pin_set(LED_4);
 }
 }
 }
}

 
 Could someone tell me how I can retrive the device name?

Balaji Srinivasan · Accepted Answer

Hi Joe, 
 @TODO JM: is there a better way? 
 The UUID of the Device name characteristic is 0x2A00. So you can do something like this.. 
 [i]if (p_ble_evt->evt.gatts_evt.params.write.context.char_uuid == BLE_UUID_GAP_CHARACTERISTIC_DEVICE_NAME)
[/i]
instead of 
 if (p_evt_write->handle == 3) 
 The macro BLE_UUID_GAP_CHARACTERISTIC_DEVICE_NAME is defined to 0x2A00 in ble_types.h. 
 @How to access the Device Name 
 You can retrieve the device name from the field p_ble_evt->evt.gatts_evt.params.write.data . The length of the device name will be in p_ble_evt->evt.gatts_evt.params.write.len . 
 Hope this helps. 
 Cheers,
Balaji