How to enable gatt indication/notification between Android and nrf51 devices?

RE: How to enable gatt indication/notification between Android and nrf51 devices?

Hung Bui — Wed, 28 Dec 2016 12:00:21 GMT

You are right, Emil. I didn't spot that.

RE: How to enable gatt indication/notification between Android and nrf51 devices?

Hung Bui — Fri, 23 Dec 2016 13:37:31 GMT

I don't think any problem there. Note that you only setCharacteristicNotification() once after you get connected, you don't have to set it all the time.

characteristic.setValue(data_to_write); has nothing to do with enabling CCCD, they are 2 separated write command.

RE: How to enable gatt indication/notification between Android and nrf51 devices?

Mitch996 — Fri, 23 Dec 2016 09:28:43 GMT

Hello, will it be a problem that I setCharacteristicNotification() RIGHT BEFORE I send the data? See code below:

if ((charaProp | BluetoothGattCharacteristic.PROPERTY_NOTIFY) > 0) {
                        mNotifyCharacteristic = characteristic;
                        mBluetoothLeService.setCharacteristicNotification(
                                characteristic, true);
characteristic.setValue(data_to_write);

RE: How to enable gatt indication/notification between Android and nrf51 devices?

Hung Bui — Thu, 22 Dec 2016 12:23:34 GMT

Hi,

It's just how BLE works. If a GATT client (in this case your phone) want to receive notification from the GATT server (your nRF51) it have to enable CCCD (write 0x01 to it) on the server. This is telling the server that "OK, I want to receive notification from you, you can send me whenever you want."

On Android, you enable CCCD by using [setCharacteristicNotification()](developer.android.com/.../BluetoothGatt.html, boolean)) .

I would suggest you to have a look at our example app, such as the nRF Blinky app or the nRF UART app.