Please refer my code

Qt Code: 
  1. #include "bluetoothupdater.h"
  2.  
  3. BluetoothUpdater::BluetoothUpdater()
  4. {
  5.     QBluetoothDeviceDiscoveryAgent* discovery = new QBluetoothDeviceDiscoveryAgent();
  6.  
  7.     connect(discovery, &QBluetoothDeviceDiscoveryAgent::deviceDiscovered, [&] (const QBluetoothDeviceInfo &device)
  8.     {
  9.         if(device.name() == "Targ")
  10.         {
  11.             qDebug() << "Found new device:" << device.name();
  12.             ptrQBluetoothDeviceInfo = new QBluetoothDeviceInfo(QBluetoothAddress(device.address()), device.name(), 0);
  13.             m_control = new QLowEnergyController(*ptrQBluetoothDeviceInfo);
  14.             m_control->connectToDevice();
  15.             m_control->discoverServices();
  16.             //connect(m_control, &QLowEnergyService::stateChanged, this, &BluetoothUpdater::service    serviceDiscovered, this, &BluetoothUpdater::serviceDiscovered);
  17.             connect(m_control, &QLowEnergyController::serviceDiscovered, this, &BluetoothUpdater::serviceDiscovered);
  18.             connect(m_control, &QLowEnergyController::discoveryFinished, this, &BluetoothUpdater::serviceScanDone);
  19.         }
  20.     });
  21.  
  22.     //connect(discovery, &QBluetoothDeviceDiscoveryAgent::deviceDiscovered, this, &BluetoothUpdater::addDevice);
  23.     discovery->setLowEnergyDiscoveryTimeout(5000);
  24.     discovery->start(QBluetoothDeviceDiscoveryAgent::LowEnergyMethod);
  25. }
  26.  
  27. void BluetoothUpdater::serviceScanDone()
  28. {
  29.     qDebug() << "Service scan done.";
  30.  
  31.     if (m_foundHeartRateService)
  32.     {
  33.         qDebug() << m_foundHeartRateService;
  34.         m_service = m_control->createServiceObject(QBluetoothUuid(DFUService));
  35.         qDebug() << m_service;
  36.     }
  37.  
  38.     if (m_service)
  39.     {
  40.         qDebug() << "DFU Service found";
  41.         m_service->discoverDetails();
  42.         connect(m_service, &QLowEnergyService::stateChanged, this, &BluetoothUpdater::serviceStateChanged);
  43.         connect(m_service, &QLowEnergyService::characteristicChanged, this, &BluetoothUpdater::updateValue);
  44.         connect(m_service, &QLowEnergyService::descriptorWritten, this, &BluetoothUpdater::confirmedDescriptorWrite);
  45.     }
  46.     else
  47.     {
  48.         qDebug() << "DFU Service not found.";
  49.     }
  50. }
  51.  
  52. void BluetoothUpdater::serviceDiscovered(const QBluetoothUuid &gatt)
  53. {
  54.     if (gatt == QBluetoothUuid(DFUService))
  55.     {
  56.         qDebug() << "DFU service discovered.";
  57.         m_foundHeartRateService = true;
  58.     }
  59. }
  60.  
  61. void BluetoothUpdater::serviceStateChanged(QLowEnergyService::ServiceState state)
  62. {
  63.     if(state == QLowEnergyService::ServiceDiscovered)
  64.     {
  65.         ControlPointChar = m_service->characteristic(QBluetoothUuid(ControlPointUUID));
  66.         if(ControlPointChar.isValid())
  67.         {
  68.             qDebug() << "Control Point Characteristic Found";           
  69.             m_service->writeCharacteristic(ControlPointChar, QByteArray::fromHex("0601"), QLowEnergyService::WriteWithResponse);
  70.         }
  71.         else
  72.         {
  73.             qDebug() << "Control Point Characteristic Not Found";
  74.         }
  75.         ControlPointDesc = ControlPointChar.descriptor(QBluetoothUuid::ClientCharacteristicConfiguration);
  76.         if (ControlPointDesc.isValid())
  77.         {
  78.             qDebug() << "Descriptor";
  79.             m_service->writeDescriptor(ControlPointDesc, QByteArray::fromHex("0100"));
  80.         }
  81.     }
  82. }
  83.  
  84. void BluetoothUpdater::updateValue(const QLowEnergyCharacteristic &c, const QByteArray &value)
  85. {
  86.     qDebug() << "updateValue, c.uuid:" << c.uuid();
  87.     qDebug() << "updateValue, value:" << value;
  88. }
  89.  
  90. void BluetoothUpdater::confirmedDescriptorWrite(const QLowEnergyDescriptor &d, const QByteArray &value)
  91. {
  92.     qDebug() << "confirmedDescriptorWrite:" << value;
  93.     if (d.isValid() && d == ControlPointDesc && value == QByteArray::fromHex("0000"))
  94.     {
  95.         qDebug() << "Inside confirmedDescriptorWrite";
  96.         m_control->disconnectFromDevice();
  97.         delete m_service;
  98.         m_service = nullptr;
  99.     }
  100. }
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Qt Code: 
  1. m_service->writeCharacteristic(ControlPointChar, QByteArray::fromHex("0601"), QLowEnergyService::WriteWithResponse);
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does not work