Added inputOverflow flag so that when we get behind executing GCode c…

…ommands, and stop reading serial input, when we come back we resynchronize with serial to ensure nothing got missed. Might address seemecnc#16.

Repetier Firmware/Repetier/gcode.cpp

@@ -37,6 +37,7 @@ uint8_t  GCode::wasLastCommandReceivedAsBinary = 0; ///< Was the last successful
 uint8_t  GCode::commentDetected = false; ///< Flags true if we are reading the comment part of a command.
 uint8_t  GCode::binaryCommandSize; ///< Expected size of the incoming binary command.
 bool     GCode::waitUntilAllCommandsAreParsed = false; ///< Don't read until all commands are parsed. Needed if gcode_buffer is misused as storage for strings.
+bool     GCode::inputOverflow = false; ///< After exiting waitUntilAllCommandsAreParsed, purge the serial port.
 uint32_t GCode::lastLineNumber = 0; ///< Last line number received.
 uint32_t GCode::actLineNumber; ///< Line number of current command.
 int8_t   GCode::waitingForResend = -1; ///< Waiting for line to be resend. -1 = no wait.
@@ -329,9 +330,29 @@ It must be called frequently to empty the incoming buffer.
 */
 void GCode::readFromSerial()
 {
-    if(bufferLength >= GCODE_BUFFER_SIZE) return; // all buffers full
-    if(waitUntilAllCommandsAreParsed && bufferLength) return;
-    waitUntilAllCommandsAreParsed = false;
+    if(bufferLength >= GCODE_BUFFER_SIZE) {
+        // The command buffer is full.  Can't accept any new commands, so wait until we've popped at least one.
+        // But, while we're not reading from the serial port, we can't know how long it's been or whether we've missed input.
+        // So, drain all the commands, then ask the controller to start over.
+        waitUntilAllCommandsAreParsed = true;
+        inputOverflow = true;
+        return;
+    }
+    if (waitUntilAllCommandsAreParsed) {
+        if (bufferLength) {
+            // There are still commands to execute, so finish them.
+            return;
+        } else {
+            // We're out of commands.  Now start parsing again.
+            waitUntilAllCommandsAreParsed = false;
+            if (inputOverflow) {
+                // And, let the controller know that we might have missed serial input since the last command processed.
+                requestResend();
+                inputOverflow = false;
+            }
+        }
+    }
+
     millis_t time = HAL::timeInMilliseconds();
     if(!HAL::serialByteAvailable())
     {

Repetier Firmware/Repetier/gcode.h

@@ -213,6 +213,7 @@ class GCode   // 52 uint8_ts per command needed
     static uint8_t commentDetected; ///< Flags true if we are reading the comment part of a command.
     static uint8_t binaryCommandSize; ///< Expected size of the incoming binary command.
     static bool waitUntilAllCommandsAreParsed; ///< Don't read until all commands are parsed. Needed if gcode_buffer is misused as storage for strings.
+    static bool inputOverflow; ///< After exiting waitUntilAllCommandsAreParsed, purge the serial port.
     static uint32_t lastLineNumber; ///< Last line number received.
     static uint32_t actLineNumber; ///< Line number of current command.
     static int8_t waitingForResend; ///< Waiting for line to be resend. -1 = no wait.