GATT server definition

[Mark81]

Starting from official Qt5 examples I wrote a very short piece of code which defines a GATT server characteristic:

QLowEnergyCharacteristicData chrCommand;
chrCommand.setUuid(UUID_CHR_COMMAND);
chrCommand.setValue(QByteArray(2, 0));
chrCommand.setProperties(QLowEnergyCharacteristic::Write);
const QLowEnergyDescriptorData clientConfigCommand(QBluetoothUuid::ClientCharacteristicConfiguration, QByteArray(2, 0));
chrCommand.addDescriptor(clientConfigCommand);

Then I set up the server itself:

advertisingData.setDiscoverability(QLowEnergyAdvertisingData::DiscoverabilityGeneral);
advertisingData.setIncludePowerLevel(false);
advertisingData.setLocalName("test");
advertisingData.setServices(QList<QBluetoothUuid>() << UUID_ADV_MIRROR);

QLowEnergyServiceData srvService;
srvService.setType(QLowEnergyServiceData::ServiceTypePrimary);
srvService.setUuid(UUID_SRV_SERVICE);
srvService.addCharacteristic(chrCommand);

leController = QLowEnergyController::createPeripheral();
service = leController->addService(srvService);
leController->startAdvertising(QLowEnergyAdvertisingParameters(), advertisingData, advertisingData);

Where all UUIDs constants are just my own random UUIDs.
It works and I can discover, bond, and write the 2-bytes to my characteristic.

I'm reading though both the Qt5 and BLE documentations but I've still some questions I cannot answer by myself:

• how to define a characteristic with longer payload? Say a 16-byte long "string" array?

• what is the maximum length of a single characteristic?

• what is the maximum length of all characteristics?

• the localName should be summed in the previous size?