Added sanity check if there is a command active but no data can be read on the serial line

src/com.cpp

@@ -21,7 +21,12 @@ void T_com::writeToSerial(const QByteArray &data, uint16_t sendLength)
     sendBuffer=data;
     sendLen=sendLength;
 
-    if (readCmds.size() == 0) { // no other read command active
+    // logic: exactly one command is sent to DC. no other command can be sent
+    // until the respond has been read from the serial line.
+
+    static int errorCnt = 0;
+
+    if (readCmds.size() == 0) { // no other read command active: ok
         if (CatSerial->isOpen())
         {
             if (CatSerial->error() != QSerialPort::NoError) {
@@ -53,14 +58,32 @@ void T_com::writeToSerial(const QByteArray &data, uint16_t sendLength)
                     return;
                 }
             }
-            readCmds.append(data.constData()[2]);
+
+            // save last command sent.
+            readCmds.append(data.constData()[2]); // 2: index of the last command
+
         } else {
             qCritical() << __func__ << ":" << __LINE__
                         << "ERROR sending" << data.toHex(':') << "port is not open";
         }
     } else {
-       qCritical() << __func__ << "" << __LINE__ << "ERROR detected active read cmd" << readCmds[0];
-       readCmds.clear();
+        qCritical() << __func__ << "" << __LINE__ << "ERROR detected active read cmd" << readCmds[0];
+        if (CatSerial->isOpen()) {
+            int availableBytes = CatSerial->bytesAvailable();
+            qCritical() << __func__ << "" << __LINE__ << "ERROR available bytes" << availableBytes;
+            if (availableBytes == 0) {
+                errorCnt += 1;
+                if (errorCnt > 100) {
+                    readCmds.clear();
+                    errorCnt = 0;
+                }
+            } else {
+                errorCnt = 0;
+            }
+        } else {
+            qCritical() << __func__ << ":" << __LINE__
+                        << "ERROR sending" << data.toHex(':') << "port is not open";
+        }
     }
 }
 

src/datIf.cpp

@@ -551,26 +551,40 @@ char T_datif::loadRecDataFromFrame()
     if (myDCIF && myDCIF->getSerialPort()) {
         QVector<uint16_t> &readCmds = myDCIF->getSerialPort()->getReadCmds();
 
-        if (readCmds.size() == 1) {
+        if (readCmds.size() == 1) { // there can be only one command been sent to the DC
+            // the command number active at the moment must be the same as the saved one
             if (readSource == myDCIF->getReadSource() && readSource == readCmds[0]) {
+                // maybe we have sent a explicit request for a test-response
                 if (waitForTestResponse) {
                     if (readCmds[0] == CMD2DC_TestSerial) {
                         if (QString(QByteArray((char const *)receivedData, RdDleng)) == "< SlaveResponse") {
                             waitForTestResponse = false;
-                            ((hwapi *)parent())->dc_autoRequest(true);
+                            qCritical() << __func__ << ":" << __LINE__ << "turn on auto-request";
+                            ((hwapi *)parent())->dc_autoRequest(true); // return autorequest to true
+                        } else {
+                            qCritical() << __func__ << ":" << __LINE__ << "received wrong test-response"
+                                        << QString(QByteArray((char const *)receivedData, RdDleng));
                         }
                     }
+                } else {
+                    // usual handling of response
                 }
                 readCmds.clear();
-            } else {
+            } else { // error
                 qCritical() << __func__ << ":" << __LINE__ << ":" << readSource << myDCIF->getReadSource() << readCmds[0];
                 qCritical() << __func__ << ":" << __LINE__ << ":" << QByteArray((char const *)receivedData, RdDleng).toHex(':');
                 readCmds.clear();
                 return 0;
             }
         } else {
+            // error: read commands has not size 1 as it should be: turn off
+            // auto requests and send explicit request for test-response:
+            // once this response has been received, turn on the autmatic requests
+            // again.
             readCmds.clear();
             if (parent()) {
+                qCritical() << __func__ << ":" << __LINE__ << "turn off auto-request";
+                qCritical() << __func__ << ":" << __LINE__ << "send request for test-response";
                 waitForTestResponse = true;
                 ((hwapi *)parent())->dc_autoRequest(false);
                 ((hwapi *)parent())->dc_requTestResponse();