Detect which handle needs to be notified to the BLE Client

RE: Detect which handle needs to be notified to the BLE Client

Petter Myhre — Thu, 29 Dec 2016 14:27:31 GMT

Great! Thanks for sharing the code snippet :)

RE: Detect which handle needs to be notified to the BLE Client

Tomi — Thu, 29 Dec 2016 14:14:35 GMT

Wow, thanks Petter, it works out of the box! I ended up at with this piece of code, where I catch ble events inside function static void on_ble_evt(ble_evt_t * p_ble_evt):

case BLE_GATTS_EVT_WRITE:
        { // <-- this is necessary, since in C there isn't any clause that allows for a "labeled declaration" in lines below.
        	uint16_t handle_received = p_ble_evt->evt.gatts_evt.params.write.handle;
        	uint16_t batt_cccd = m_skiwatt.battery_char_handles.cccd_handle;
        	uint16_t button_cccd = m_skiwatt.button_char_handles.cccd_handle;

        	NRF_LOG_DEBUG("Write handle: %08x\r\n", handle_received);
        	if (handle_received == batt_cccd)
        	{
        		curr_cccd = CCCD_IS_BATTERY_1_LEVEL;
        		NRF_LOG_DEBUG("User ask for battery notifications\r\n");
        	}
        	if (handle_received == button_cccd)
			{
        		curr_cccd = CCCD_IS_BUTTON;
				NRF_LOG_DEBUG("User ask for button notifications\r\n");
			}
        } break;

Hope someone will find it useful.

RE: Detect which handle needs to be notified to the BLE Client

Petter Myhre — Thu, 29 Dec 2016 11:26:10 GMT

I'm assuming that you meant BLE_GATTS_EVT_WRITE, which is 0x50, not BLE_GATTC_EVT_CHAR_DISC_RSP.

You need to compare the attribute handle in the write event with the attribute handles of the CCCDs.

The attribute handle in the write event can be found at

p_ble_evt->evt.gatts_evt.params.write.handle

The attribute handles of the CCCDs will be available in the ble_gatts_char_handles_t struct after you have called sd_ble_gatts_characteristic_add().