Index: sources/bluetooth/BluetoothInterface.cpp
===================================================================
diff -u -rc447018bc6c50996f402e01f951d40b17a120705 -r1c97eebc80b33b429fa6e9489584ce3bf24f0bbc
--- sources/bluetooth/BluetoothInterface.cpp	(.../BluetoothInterface.cpp)	(revision c447018bc6c50996f402e01f951d40b17a120705)
+++ sources/bluetooth/BluetoothInterface.cpp	(.../BluetoothInterface.cpp)	(revision 1c97eebc80b33b429fa6e9489584ce3bf24f0bbc)
@@ -452,9 +452,7 @@
     // This indicates the local/host bluetooth have connected passively to the remote device
     _reconnectionActive = true;
 
-    if ( _local->pairingStatus(vAddress) == QBluetoothLocalDevice::Unpaired ) {
-        requestDevicePairing(vAddress);
-    } else {
+    if ( _local->pairingStatus(vAddress) != QBluetoothLocalDevice::Unpaired ) {
         if ( isDeviceValid() ) {
             _device->connectToDevice();
         }
@@ -511,15 +509,8 @@
 
             data.pair = isPaired || isAuthPaired;
 
-            if(data.pair){
-                // Enable the polling since previously paired device found
-                _reconnectionActive = true;
-
-                // sets up the bluetooth device info to create the device later for pairing
-                _temp = QBluetoothDeviceInfo(QBluetoothAddress(data.addr), data.name, QBluetoothDeviceInfo::HealthBloodPressureMonitor);
-
-                // using signal to re-use the slot function of a device selected
-                emit _BluetoothInterface.didDeviceSelect(data);
+            if ( data.pair ) {
+                requestDevicePairing(data);
             }
             emit didDeviceChange(data);
             NOTIFY_SCAN_FOUND
@@ -569,21 +560,22 @@
  */
 void BluetoothInterface::onDeviceSelect(const BluetoothDeviceData &vDevice) {
     stopScan();
-    _temp = QBluetoothDeviceInfo(QBluetoothAddress(vDevice.addr), vDevice.name, QBluetoothDeviceInfo::HealthBloodPressureMonitor);
-
-    requestDevicePairing(QBluetoothAddress(vDevice.addr));
+    requestDevicePairing(vDevice);
 }
 
 /*!
  * \brief   BluetoothInterface::requestDevicePairing
  * \details Request the pairing of the local/host bluetooth with the remote device
- * \param   vAddress - the address of the remote device
+ * \param   vDevice - The device data
  */
-void BluetoothInterface::requestDevicePairing(const QBluetoothAddress &vAddress) {
+void BluetoothInterface::requestDevicePairing(const BluetoothDeviceData  &vDevice) {
     if ( ! isLocalValid() ) return;
 
     NOTIFY_LOCAL_PAIRING
-    _local->requestPairing(vAddress, QBluetoothLocalDevice::AuthorizedPaired);
+
+    _temp = QBluetoothDeviceInfo(QBluetoothAddress(vDevice.addr), vDevice.name, QBluetoothDeviceInfo::HealthBloodPressureMonitor);
+    _isPairingKeyWritten = false;
+    _local->requestPairing(QBluetoothAddress(vDevice.addr), QBluetoothLocalDevice::AuthorizedPaired);
 }
 
 /*!
@@ -596,9 +588,8 @@
     Q_UNUSED(addr)
     if( pair == QBluetoothLocalDevice::Paired || pair == QBluetoothLocalDevice::AuthorizedPaired) {
         connectToDevice();
-    } else {
-        // not handling unpairing case
     }
+    // Else is the unpaired completion case
 }
 
 void BluetoothInterface::onAttributeResponse(const DeviceBluetoothPairedQueryResponseData &vData)
@@ -644,11 +635,7 @@
 
     NOTIFY_DEVICE_CONNECT
     _reconnectionActive = false;
-    if(_local->pairingStatus(_device->remoteAddress()) == QBluetoothLocalDevice::Unpaired) {
-        requestDevicePairing(_device->remoteAddress());
-    } else {
-        discoverServices();
-    }
+    discoverServices();
 }
 
 /*!
@@ -731,7 +718,6 @@
     {
         interpretBloodPressure(vValue);
     }
-    qDebug() << "---------" << vCharacteristic.name() << vValue;
 }
 
 /*!
@@ -744,10 +730,43 @@
  */
 void BluetoothInterface::onServiceCharacteristicRead    (const QLowEnergyCharacteristic &vCharacteristic, const QByteArray &vValue) {
     QLowEnergyService *service = reinterpret_cast<QLowEnergyService *>(sender());
+
     NOTIFY_DETAILS_READ
+    if ( isVendorSpecificService(service) && isDevicePairingCharacteristicUuid(vCharacteristic) ) {
+        if ( !_isPairingKeyWritten &&  (vValue.at(0) == _deviceConfirmKeyWriteCodeSuccess ) ) {
+            // write the key for pairing retention
+            writeDevicePairingKey();
+            _isPairingKeyWritten = true;
+        }
+        if(vValue.at(0) == '\x80') {
+            // No-op key write responded with a success code
+        }
+    }
 }
 
 /*!
+ * \brief   BluetoothInterface::isDevicePairingCharacteristicUuid
+ * \details Indicate whether the characteristic passed is the device pairing characteristic of the vendor specific service
+ * \return true if the characteristic is the device pairing/bonding characteristic, false otherwise
+ * \param   vCharacteristic - The characteristic object
+ */
+bool BluetoothInterface::isDevicePairingCharacteristicUuid (const QLowEnergyCharacteristic &vCharacteristic) {
+    QString characteristicUuid = vCharacteristic.uuid().toString();
+    return (characteristicUuid.compare(_devicePairingBondCharacteristicUuid, Qt::CaseInsensitive) == 0);
+}
+
+/*!
+ * \brief   BluetoothInterface::isVendorSpecificService
+ * \details Indicate whether the service passed has the uuid of a vendor specific service
+ * \return true if the service is a vendor specific service, false otherwise
+ * \param   vService - The service object
+ */
+bool BluetoothInterface::isVendorSpecificService (const QLowEnergyService *vService) {
+    QString serviceUuid = vService->serviceUuid().toString();
+    return (serviceUuid.compare(_vendorSpecificServiceUuid, Qt::CaseInsensitive) == 0);
+}
+
+/*!
  * \brief   BluetoothInterface::onServiceCharacteristicWritten
  * \details This signal handler is called when the value of characteristic is successfully changed to new vValue.
  *          The change must have been triggered by calling writeCharacteristic(). If the write operation is not successful,
@@ -759,6 +778,10 @@
  */
 void BluetoothInterface::onServiceCharacteristicWritten (const QLowEnergyCharacteristic &vCharacteristic, const QByteArray &vValue) {
     QLowEnergyService *service = reinterpret_cast<QLowEnergyService *>(sender());
+    if ( isVendorSpecificService(service) ) {
+        service->readCharacteristic(vCharacteristic);
+    }
+
     NOTIFY_DETAILS_WRITE
 }
 
@@ -813,6 +836,11 @@
     switch (vState) {
     case QLowEnergyService::ServiceDiscovered   : {
         NOTIFY_SERVICE_DETAILS_DONE
+
+        if ( isVendorSpecificService(service) && !_isPairingKeyWritten) {
+            enableKeyProgramming();
+        }
+
         switch( service->serviceUuid().toUInt32() ) {
         case QBluetoothUuid::BloodPressure:
             enableNotify();
@@ -1131,6 +1159,13 @@
  */
 void BluetoothInterface::makeServices(const QBluetoothUuid &vService)
 {
+    // creating QBluetoothUuid object for the vendor service uuid string creates
+    // an ambiguous object, so doing string compare
+    if (vService.toString().compare(_vendorSpecificServiceUuid) == 0) {
+        _serviceVendorSpecific =    _device->createServiceObject(vService, this);
+        initConnectionsService      (_serviceVendorSpecific      );
+        return;
+    }
     if (vService == QBluetoothUuid  (QBluetoothUuid::DeviceInformation  )) {
         _serviceDeviceInformation   = _device->createServiceObject(vService, this);
         initConnectionsService      (_serviceDeviceInformation   );
@@ -1161,6 +1196,11 @@
 void BluetoothInterface::discoverServicesDetails()
 {
     if ( ! isValid() ) return;
+
+    if (                        _serviceVendorSpecific      ) {
+        NOTIFY_SERVICE_DETAILS (_serviceVendorSpecific      )
+                                _serviceVendorSpecific      ->discoverDetails();
+    }
     if (                        _serviceDeviceInformation   ) {
         NOTIFY_SERVICE_DETAILS (_serviceDeviceInformation   )
                                 _serviceDeviceInformation   ->discoverDetails();
@@ -1188,6 +1228,11 @@
  */
 void BluetoothInterface::quitServices() {
     NOTIFY_SERVICE_DONE
+
+    if (        _serviceVendorSpecific   ) {
+        delete  _serviceVendorSpecific   ;
+                _serviceVendorSpecific   = nullptr;
+    }
     if (        _serviceDeviceInformation   ) {
         delete  _serviceDeviceInformation   ;
                 _serviceDeviceInformation   = nullptr;
@@ -1209,8 +1254,43 @@
 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // ~~~~~ Characteristics
 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+/*!
+ * \brief   BluetoothInterface::enableKeyProgramming
+ * \details Write the special key to enable key programming mode for the pairing retention
+ */
+void BluetoothInterface::enableKeyProgramming() {
+    if ( ! _serviceVendorSpecific ) {
+        NOTIFY_SERVICE_INVALID
+        return;
+    }
 
+    // write the special value to the characteristic to enable key programming mode
+    const QLowEnergyCharacteristic detailBPMeas = _serviceVendorSpecific->characteristic(QBluetoothUuid(_devicePairingBondCharacteristicUuid));
+    if ( detailBPMeas.isValid() ) {
+        _serviceVendorSpecific->writeCharacteristic(detailBPMeas, QByteArray::fromHex(_enableKeyProgrammingString));
+    }
+}
+
 /*!
+ * \brief   BluetoothInterface::writeDevicePairingKey
+ * \details Write the pairing key value to the bonding characteristic of the vendor specific service.
+ *          This allows the device to maintain the pairing state with the remote device without the need to re-pair
+ *          after the initial pairing. The device will be able to reconnect and retrieve measurements without pairing first.
+ */
+void BluetoothInterface::writeDevicePairingKey() {
+    if ( ! _serviceVendorSpecific ) {
+        NOTIFY_SERVICE_INVALID
+            return;
+    }
+
+    // set the value of the pairing key on the device
+    const QLowEnergyCharacteristic detailBPMeas = _serviceVendorSpecific->characteristic(QBluetoothUuid(_devicePairingBondCharacteristicUuid));
+    if ( detailBPMeas.isValid() ) {
+        _serviceVendorSpecific->writeCharacteristic(detailBPMeas, QByteArray::fromHex(_devicePairingKeyString));
+    }
+}
+
+/*!
  * \brief   BluetoothInterface::enableNotify
  * \details Enabling the Blood Pressure measurement notification.
  *          This has to be done to first get the OK on the Bluetooth Cuff device.