How to get UUID of Characteristic from a ble_evt_t?

[Shiba Inu]

Hello:

I am writing a BLE profile involving several characteristics. One of the characteristics is an operation code (read/write) tunnel.

Each time a BLE central device writes to the BLE peripheral (nRF51 10028 board), I would like to check the characteristic being written to, so that the application can properly respond to whatever operation is requested by the central.

I figure that I would do this by getting the UUID of the characteristic that was written. Any write to a characteristic will trigger a BLE event (in the on_ble_evt() event handler in main.c) with a header.evt_uid of BLE_GATTS_EVT_WRITE.

How would I go about getting the UUID of the characteristic being written (i.e., the one triggering the BLE event handler, which throws the BLE_GATTS_EVT_WRITE)?

Is this the right way to model a central-peripheral, command-response relationship? Is checking the UUID of the written characteristic the best way to respond to written commands?

---

static void command_characterstic_write_evt_dispatch(ble_evt_t * p_ble_evt)
{
//Get characteristic UUID and handle actions from there (or check respective value of each characteristic (compared to previous value) and do proper action). 
ble_uuid_t evt_uuid = p_ble_evt->evt.gattc_evt.params.char_val_by_uuid_read_rsp;
SEGGER_RTT_printf(0,"\n Updated characteristic with handle (UUID) %o", evt_uuid);
switch(evt_uuid)
{
	case BLE_UUID_COMMAND_BUFFER_TUNNEL_CHARACTERISTIC_UUID: 

	default:
		break;
} }

Where the characteristic UUID is 0x2000 or BLE_UUID_COMMAND_BUFFER_TUNNEL_CHARACTERISTIC_UUID

[Petter Myhre]

Your code doesn't make sense to me. Does it work? Have you tested it? If you get a BLE_GATTS_EVT_WRITE event, the UUID should be in p_ble_evt->evt.gatts_evt.params.write.uuid

[Shiba Inu]

Thank you. I should've made it more clearer in my question that all I really was trying to do was to retrieve the UUID of a p_ble_evt that I receive from a BLE write event.