Do not work with serial port pointer if it has been disconnected

assets/qml/Windows/Console.qml

@@ -21,6 +21,7 @@
  */
 
 import QtQuick 2.12
+import Qt.labs.settings 1.0
 import QtQuick.Layouts 1.12
 import QtQuick.Controls 2.12
 
@@ -38,6 +39,14 @@ Control {
     property alias text: _console.text
     readonly property color consoleColor: Qt.rgba(142/255, 205/255, 157/255, 1)
 
+    //
+    // Save settings
+    //
+    Settings {
+        category: "Console"
+        property alias writeEnabled: writeSw.checked
+    }
+
     //
     // Connections with serial manager
     //
@@ -105,6 +114,15 @@ Control {
         RowLayout {
             Layout.fillWidth: true
 
+            Switch {
+                id: writeSw
+                checked: true
+                Layout.alignment: Qt.AlignHCenter
+                onCheckedChanged: CppSerialManager.writeEnabled = checked
+                opacity: CppSerialManager.readWrite ? 1 : (CppSerialManager.connected ? 0.5 : 1)
+                Behavior on opacity {NumberAnimation{}}
+            }
+
             TextField {
                 id: _tf
                 height: 24
@@ -112,6 +130,7 @@ Control {
                 Layout.fillWidth: true
                 color: root.consoleColor
                 font.family: app.monoFont
+                opacity: enabled ? 1 : 0.5
                 enabled: CppSerialManager.readWrite
                 palette.base: Qt.rgba(18/255, 18/255, 24/255, 1)
                 placeholderText: qsTr("Send data to device") + "..." + CppTranslator.dummy

assets/qml/Windows/DeviceManager.qml

@@ -130,6 +130,7 @@ Control {
         Label {
             text: qsTr("COM Port") + ":" + CppTranslator.dummy
         } ComboBox {
+            id: portSelector
             Layout.fillWidth: true
             model: CppSerialManager.portList
             currentIndex: CppSerialManager.portIndex
@@ -137,6 +138,14 @@ Control {
                 if (CppSerialManager.portIndex !== currentIndex)
                     CppSerialManager.portIndex = currentIndex
             }
+
+            Connections {
+                target: CppSerialManager
+                function onAvailablePortsChanged() {
+                    if (portSelector.currentIndex !== CppSerialManager.portIndex)
+                        portSelector.currentIndex = CppSerialManager.portIndex
+                }
+            }
         }
 
         //

src/SerialManager.cpp

@@ -210,6 +210,14 @@ int SerialManager::maxBufferSize() const
     return m_maxBufferSize;
 }
 
+/**
+ * Returns @c true if we want to open the port in RW mode
+ */
+bool SerialManager::writeEnabled() const
+{
+    return m_writeEnabled;
+}
+
 /**
  * Returns the size of the data received (and successfully read) from the
  * serial device.
@@ -473,6 +481,8 @@ void SerialManager::disconnectDevice()
 
         // Reset pointer
         m_port = nullptr;
+        m_portIndex = 0;
+        emit availablePortsChanged();
 
         // Reset received bytes
         m_receivedBytes = 0;
@@ -554,8 +564,8 @@ void SerialManager::setPort(const quint8 portIndex)
         return;
 
     // Update port index variable & disconnect from current serial port
-    m_portIndex = portIndex;
     disconnectDevice();
+    m_portIndex = portIndex;
 
     // Ignore the first item of the list (Select Port)
     if (portIndex > 0)
@@ -587,28 +597,22 @@ void SerialManager::setPort(const quint8 portIndex)
                     this,     SLOT(handleError(QSerialPort::SerialPortError)));
             // clang-format on
 
-            // Try to open the serial port in R/W mode
+            // Select open mode for serial port
-            if (port()->open(QIODevice::ReadWrite))
+            auto mode = QIODevice::ReadOnly;
+            if (writeEnabled())
+                mode = QIODevice::ReadWrite;
+
+            // Try to open the port in R/RW
+            if (port()->open(mode))
             {
                 emit connectedChanged();
                 LOG_INFO() << Q_FUNC_INFO
                            << "Serial port opened successfully in RW mode";
             }
 
-            // Try to open the serial port only for reading
-            else if (port()->open(QIODevice::ReadOnly))
-            {
-                emit connectedChanged();
-                LOG_INFO() << Q_FUNC_INFO
-                           << "Serial port opened successfully in READ mode";
-            }
-
             // Close serial port on error
             else
-            {
                 disconnectDevice();
-                LOG_INFO() << "Serial port open error" << port()->errorString();
-            }
         }
     }
 
@@ -617,6 +621,23 @@ void SerialManager::setPort(const quint8 portIndex)
     LOG_INFO() << "Serial port selection set to" << portName();
 }
 
+/**
+ * Enables/disables RW mode
+ */
+void SerialManager::setWriteEnabled(const bool enabled)
+{
+    m_writeEnabled = enabled;
+
+    if (connected())
+    {
+        auto index = portIndex();
+        disconnectDevice();
+        setPort(index);
+    }
+
+    emit writeEnabledChanged();
+}
+
 /**
  * @brief SerialManager::setParity
  * @param parityIndex
@@ -992,7 +1013,7 @@ void SerialManager::handleError(QSerialPort::SerialPortError error)
     if (error != QSerialPort::NoError)
     {
         auto errorStr = port()->errorString();
-        setPort(0);
+        disconnectDevice();
         NiceMessageBox(tr("Critical serial port error"), errorStr);
     }
 }

src/SerialManager.h

@@ -55,6 +55,10 @@ class SerialManager : public QObject
                READ maxBufferSize
                WRITE setMaxBufferSize
                NOTIFY maxBufferSizeChanged)
+    Q_PROPERTY(bool writeEnabled
+               READ writeEnabled
+               WRITE setWriteEnabled
+               NOTIFY writeEnabledChanged)
     Q_PROPERTY(QString startSequence
                READ startSequence
                WRITE setStartSequence
@@ -115,6 +119,7 @@ signals:
     void stopBitsChanged();
     void connectedChanged();
     void flowControlChanged();
+    void writeEnabledChanged();
     void textDocumentChanged();
     void maxBufferSizeChanged();
     void startSequenceChanged();
@@ -136,6 +141,7 @@ public:
     bool connected() const;
     QString portName() const;
     int maxBufferSize() const;
+    bool writeEnabled() const;
     QString receivedBytes() const;
     QString startSequence() const;
     QString finishSequence() const;
@@ -167,6 +173,7 @@ public slots:
     void disconnectDevice();
     void sendData(const QString &data);
     void setPort(const quint8 portIndex);
+    void setWriteEnabled(const bool enabled);
     void setParity(const quint8 parityIndex);
     void setBaudRate(const quint8 baudRateIndex);
     void setDataBits(const quint8 dataBitsIndex);
@@ -202,6 +209,7 @@ private:
     quint64 m_receivedBytes;
     quint8 m_flowControlIndex;
 
+    bool m_writeEnabled;
     int m_maxBufferSize;
 
     QString m_startSeq;