diff --git a/Documentation/GCodes.md b/Documentation/GCodes.md
index 253fb7fc81..fde8435932 100644
--- a/Documentation/GCodes.md
+++ b/Documentation/GCodes.md
@@ -101,3 +101,25 @@
* M908 - Control digital trimpot directly.
* M928 - Start SD logging (M928 filename.g) - ended by M29
* M999 - Restart after being stopped by error
+
+# Comments
+
+Comments start at a `;` (semicolon) and end with the end of the line:
+
+ N3 T0*57 ; This is a comment
+ N4 G92 E0*67
+ ; So is this
+ N5 G28*22
+
+(example taken from the [RepRap wiki](http://reprap.org/wiki/Gcode#Comments))
+
+If you need to use a literal `;` somewhere (for example within `M117`), you can escape semicolons with a `\`
+(backslash):
+
+ M117 Hello \;)
+
+`\` can also be used to escape `\` itself, if you need a literal `\` in front of a `;`:
+
+ M117 backslash: \\;and a comment
+
+Please note that hosts should strip any comments before sending GCODE to the printer in order to save bandwidth.
\ No newline at end of file
diff --git a/Marlin/Marlin_main.cpp b/Marlin/Marlin_main.cpp
index b2ebbbe518..ca1af6038c 100644
--- a/Marlin/Marlin_main.cpp
+++ b/Marlin/Marlin_main.cpp
@@ -730,103 +730,113 @@ void get_command()
serial_char = MYSERIAL.read();
if(serial_char == '\n' ||
serial_char == '\r' ||
- (serial_char == ':' && comment_mode == false) ||
serial_count >= (MAX_CMD_SIZE - 1) )
{
- if(!serial_count) { //if empty line
- comment_mode = false; //for new command
+ // end of line == end of comment
+ comment_mode = false;
+
+ if(!serial_count) {
+ // short cut for empty lines
return;
}
cmdbuffer[bufindw][serial_count] = 0; //terminate string
- if(!comment_mode){
- comment_mode = false; //for new command
- fromsd[bufindw] = false;
- if(strchr(cmdbuffer[bufindw], 'N') != NULL)
+
+ fromsd[bufindw] = false;
+ if(strchr(cmdbuffer[bufindw], 'N') != NULL)
+ {
+ strchr_pointer = strchr(cmdbuffer[bufindw], 'N');
+ gcode_N = (strtol(strchr_pointer + 1, NULL, 10));
+ if(gcode_N != gcode_LastN+1 && (strstr_P(cmdbuffer[bufindw], PSTR("M110")) == NULL) ) {
+ SERIAL_ERROR_START;
+ SERIAL_ERRORPGM(MSG_ERR_LINE_NO);
+ SERIAL_ERRORLN(gcode_LastN);
+ //Serial.println(gcode_N);
+ FlushSerialRequestResend();
+ serial_count = 0;
+ return;
+ }
+
+ if(strchr(cmdbuffer[bufindw], '*') != NULL)
{
- strchr_pointer = strchr(cmdbuffer[bufindw], 'N');
- gcode_N = (strtol(strchr_pointer + 1, NULL, 10));
- if(gcode_N != gcode_LastN+1 && (strstr_P(cmdbuffer[bufindw], PSTR("M110")) == NULL) ) {
- SERIAL_ERROR_START;
- SERIAL_ERRORPGM(MSG_ERR_LINE_NO);
- SERIAL_ERRORLN(gcode_LastN);
- //Serial.println(gcode_N);
- FlushSerialRequestResend();
- serial_count = 0;
- return;
- }
+ byte checksum = 0;
+ byte count = 0;
+ while(cmdbuffer[bufindw][count] != '*') checksum = checksum^cmdbuffer[bufindw][count++];
+ strchr_pointer = strchr(cmdbuffer[bufindw], '*');
- if(strchr(cmdbuffer[bufindw], '*') != NULL)
- {
- byte checksum = 0;
- byte count = 0;
- while(cmdbuffer[bufindw][count] != '*') checksum = checksum^cmdbuffer[bufindw][count++];
- strchr_pointer = strchr(cmdbuffer[bufindw], '*');
-
- if( (int)(strtod(strchr_pointer + 1, NULL)) != checksum) {
- SERIAL_ERROR_START;
- SERIAL_ERRORPGM(MSG_ERR_CHECKSUM_MISMATCH);
- SERIAL_ERRORLN(gcode_LastN);
- FlushSerialRequestResend();
- serial_count = 0;
- return;
- }
- //if no errors, continue parsing
- }
- else
- {
+ if( (int)(strtod(strchr_pointer + 1, NULL)) != checksum) {
SERIAL_ERROR_START;
- SERIAL_ERRORPGM(MSG_ERR_NO_CHECKSUM);
+ SERIAL_ERRORPGM(MSG_ERR_CHECKSUM_MISMATCH);
SERIAL_ERRORLN(gcode_LastN);
FlushSerialRequestResend();
serial_count = 0;
return;
}
-
- gcode_LastN = gcode_N;
//if no errors, continue parsing
}
- else // if we don't receive 'N' but still see '*'
+ else
{
- if((strchr(cmdbuffer[bufindw], '*') != NULL))
- {
- SERIAL_ERROR_START;
- SERIAL_ERRORPGM(MSG_ERR_NO_LINENUMBER_WITH_CHECKSUM);
- SERIAL_ERRORLN(gcode_LastN);
- serial_count = 0;
- return;
- }
- }
- if((strchr(cmdbuffer[bufindw], 'G') != NULL)){
- strchr_pointer = strchr(cmdbuffer[bufindw], 'G');
- switch((int)((strtod(strchr_pointer + 1, NULL)))){
- case 0:
- case 1:
- case 2:
- case 3:
- if (Stopped == true) {
- SERIAL_ERRORLNPGM(MSG_ERR_STOPPED);
- LCD_MESSAGEPGM(MSG_STOPPED);
- }
- break;
- default:
- break;
- }
-
+ SERIAL_ERROR_START;
+ SERIAL_ERRORPGM(MSG_ERR_NO_CHECKSUM);
+ SERIAL_ERRORLN(gcode_LastN);
+ FlushSerialRequestResend();
+ serial_count = 0;
+ return;
}
- //If command was e-stop process now
- if(strcmp(cmdbuffer[bufindw], "M112") == 0)
- kill();
-
- bufindw = (bufindw + 1)%BUFSIZE;
- buflen += 1;
+ gcode_LastN = gcode_N;
+ //if no errors, continue parsing
}
+ else // if we don't receive 'N' but still see '*'
+ {
+ if((strchr(cmdbuffer[bufindw], '*') != NULL))
+ {
+ SERIAL_ERROR_START;
+ SERIAL_ERRORPGM(MSG_ERR_NO_LINENUMBER_WITH_CHECKSUM);
+ SERIAL_ERRORLN(gcode_LastN);
+ serial_count = 0;
+ return;
+ }
+ }
+ if((strchr(cmdbuffer[bufindw], 'G') != NULL)){
+ strchr_pointer = strchr(cmdbuffer[bufindw], 'G');
+ switch((int)((strtod(strchr_pointer + 1, NULL)))){
+ case 0:
+ case 1:
+ case 2:
+ case 3:
+ if (Stopped == true) {
+ SERIAL_ERRORLNPGM(MSG_ERR_STOPPED);
+ LCD_MESSAGEPGM(MSG_STOPPED);
+ }
+ break;
+ default:
+ break;
+ }
+
+ }
+
+ //If command was e-stop process now
+ if(strcmp(cmdbuffer[bufindw], "M112") == 0)
+ kill();
+
+ bufindw = (bufindw + 1)%BUFSIZE;
+ buflen += 1;
+
serial_count = 0; //clear buffer
}
- else
- {
- if(serial_char == ';') comment_mode = true;
- if(!comment_mode) cmdbuffer[bufindw][serial_count++] = serial_char;
+ else if(serial_char == '\\') { //Handle escapes
+
+ if(MYSERIAL.available() > 0 && buflen < BUFSIZE) {
+ // if we have one more character, copy it over
+ serial_char = MYSERIAL.read();
+ cmdbuffer[bufindw][serial_count++] = serial_char;
+ }
+
+ //otherwise do nothing
+ }
+ else { // its not a newline, carriage return or escape char
+ if(serial_char == ';') comment_mode = true;
+ if(!comment_mode) cmdbuffer[bufindw][serial_count++] = serial_char;
}
}
#ifdef SDSUPPORT