nRF51822 notification sending

[zainab_daoud]

I'm using nRF51822 and i want to send a notification to the central to notify it for the changing of a characteristic value (major_value) after using the sd_ble_gatts_value_set ? here is my code:

 const ble_bcs_init_t * p_bcs_init;
		ble_bcs_t  *p_bcs;
		p_bcs = &m_bcs ;
		uint16_t len =4;
		uint8_t value[4];
		value[0]=0;
		value[1]=1;
		value[2]=0;
		value[3]=0;
					
		
	err_code =	sd_ble_gatts_value_set(p_bcs->beacon_maj_min_char_handles.value_handle,0,&len,value);
	 APP_ERROR_CHECK(err_code);

		if((p_bcs->conn_handle != BLE_CONN_HANDLE_INVALID) && p_bcs->is_notifying)
		 {
        ble_gatts_hvx_params_t params;
        memset(&params, 0, sizeof(params));
       // len = sizeof(uint16_t);
        params.handle   =p_bcs->beacon_maj_min_char_handles.value_handle 	;
        params.type     = BLE_GATT_HVX_NOTIFICATION;
        params.p_len    = &len;
				params.offset   = 0;
        params.p_data   = value;

         uint32_t err_code2=sd_ble_gatts_hvx(p_bcs->conn_handle, &params);
				 APP_ERROR_CHECK(err_code2);

The problem is that the central is not able to read those changes. But when cheking the value of the characteristic from the master control panel , it reads the correct value ( updated) . Is there something wrong with my code ? if so is there an example ?

[MartinBL]

Hi

Did you remember to set the proper CCCD values? You need to do this to enable notifications. Take a look at the heart rate service example (ble_app_hrs) in the SDK, for example, to see how to set up your CCCD. If you already did this, may you please post your characteristic setup code?

[kerem]

Is cccd the key for getting these notifications along with the copy of the data, in order to persist the written values? Is this documented somewhere?