[solved] infinite loop in GcodeCNCDemo…V2
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Hello,
I am presently testing the GcodeCNCDemo sketches.(arduino due, version 1.5.8 ,windows 8.1) It does run one time and move the stepper motors when entering e.g.
G00 X100 F300; in the serial monitor. It will not accept a second command. To see what is happening, I added some print commands and learned that it is not leaving the while loop in function parse number:float parsenumber(char code,float val) {
char *ptr=buffer;while(ptr && *ptr && ptr
Serial.print(“a *ptr : “); Serial.println(*ptr);
Serial.print(“a buffer :”);Serial.println( buffer);
Serial.print(“a buffer+sofar :”); Serial.println( buffer+sofar);
Serial.print(“sofar :”); Serial.println(sofar);if(*ptr==code) {
return atof(ptr+1);
}
ptr=strchr(ptr,’ ‘)+1;Serial.print(“b ptr : “); Serial.println(ptr);
Serial.print(“b *ptr : “); Serial.println(*ptr);
Serial.print(“b buffer :”);Serial.println( buffer);
Serial.print(“b buffer+sofar :”); Serial.println( buffer+sofar);}
return val;
}This gives the following output in the serial monitor, processing the commands until it runs into the semicolon :
codeCNCDemo6AxisV2 2
Commands:
G00/G01 [X/Y/Z/U/V/W(steps)] [F(feedrate)]; – linear move
G04 P[seconds]; – delay
G90; – absolute mode
G91; – relative mode
G92 [X/Y/Z/U/V/W(steps)]; – change logical position
M18; – disable motors
M100; – this help message
M114; – report position and feedrate
>G00 X100 F300;G00 X100 F300;sofar :14
ptr : G00 X100 F300;
*ptr : G
buffer :G00 X100 F300;
buffer+sofar :
in while
a ptr : G00 X100 F300;
a *ptr : G
a buffer :G00 X100 F300;
a buffer+sofar :
sofar :14
sofar :14
ptr : G00 X100 F300;
*ptr : G
buffer :G00 X100 F300;
buffer+sofar :
in while
a ptr : G00 X100 F300;
a *ptr : G
a buffer :G00 X100 F300;
a buffer+sofar :
sofar :14
b ptr : X100 F300;
b *ptr : X
b buffer :G00 X100 F300;
b buffer+sofar :
in while
a ptr : X100 F300;
a *ptr : X
a buffer :G00 X100 F300;
a buffer+sofar :
sofar :14
b ptr : F300;
b *ptr : F
b buffer :G00 X100 F300;
b buffer+sofar :
in while
a ptr : F300;
a *ptr : F
a buffer :G00 X100 F300;
a buffer+sofar :
sofar :14
sofar :14
ptr : G00 X100 F300;
*ptr : G
buffer :G00 X100 F300;
buffer+sofar :
in while
a ptr : G00 X100 F300;
a *ptr : G
a buffer :G00 X100 F300;
a buffer+sofar :
sofar :14
b ptr : X100 F300;
b *ptr : X
b buffer :G00 X100 F300;
b buffer+sofar :
in while
a ptr : X100 F300;
a *ptr : X
a buffer :G00 X100 F300;
a buffer+sofar :
sofar :14
sofar :14
ptr : G00 X100 F300;
*ptr : G
buffer :G00 X100 F300;
buffer+sofar :
in while
a ptr : G00 X100 F300;
a *ptr : G
a buffer :G00 X100 F300;
a buffer+sofar :
sofar :14
b ptr : X100 F300;
b *ptr : X
b buffer :G00 X100 F300;
b buffer+sofar :
in while
a ptr : X100 F300;
a *ptr : X
a buffer :G00 X100 F300;
a buffer+sofar :
sofar :14
b ptr : F300;
b *ptr : F
b buffer :G00 X100 F300;
b buffer+sofar :
in while
a ptr : F300;
a *ptr : F
a buffer :G00 X100 F300;
a buffer+sofar :
sofar :14
b ptr : µ
b *ptr :
b buffer :G00 X100 F300;
b buffer+sofar :
in while
a ptr : µ
a *ptr :
a buffer :G00 X100 F300;
a buffer+sofar :
sofar :14and so on…..
( I selected no line end at the bottom of the serial monitor)
The questions that arise to me particularly concern the while condition : buffer+sofar – a character array is added to an integer value. What is the value this expression should contain and where is it correctly (re)set ?
After the pointer *ptr reaches the end of the string (;), its contents seem undefined and not reset.
Furthermore, in void loop function buffer[sofar]=0; an element of an array of character is assigned an integer value.
Obviously, several ( implicit ) type conversions in my case do not work correctly and I would appreciate and I would appreciate advice for better understanding of the code and make it more robust.
Thank you very much
send newline. the latest firmware doesn’t start to process a command until it gets the ‘n’ newline character.
/**
* Look for character /code/ in the buffer and read the float that immediately follows it.
* @return the value found. If nothing is found, /val/ is returned.
* @input code the character to look for.
* @input val the return value if /code/ is not found.
**/
float parsenumber(char code,float val) {
char *ptr=buffer; // start at the beginning of buffer
while(ptr && *ptr && ptr<buffer+sofar) { // walk to the end
if(*ptr==code) { // if you find code on your walk,
return atof(ptr+1); // convert the digits that follow into a float and return it
}
ptr=strchr(ptr,' ')+1; // take a step from here to the letter after the next space
}
return val; // end reached, nothing found, return default val.
}I will update the code with these comments for everyone else.
Please feel free to submit a pull request with your improvements to the code.
buffer is the address of a block of data. Over time it is filled with characters received from the serial line.
sofar is a count of the number of bytes received from the serial line and stored starting at address buffer. In other words, buffer[sofar-1] is the last character received from the serial line and buffer+sofar is the address in memory of the last character received. When the system is ready to receive a new instruction, it sets sofar=0;ptr is an address. *ptr is the value at that address. char *ptr=buffer means “create a pointer called ptr and set the address to be the same as the address of buffer.”
Strings in C are usually terminated with a null (number 0) character. String functions like strchr() and atof() agree to this standard. *ptr == 0 is true when ptr is pointing at the end of the string of characters. When the data is being read in from serial, *ptr is set to the new character and *(ptr+1) is set to zero, every time. The value is implicitely typecast to (char)0. That way the string is never unfinished.
strchr() returns null (0) when it cannot find the character it seeks. At the end of the string ptr=strchr(ptr,’ ‘)+1 would set ptr equal to buffer+sofar+1, which would end the while() loop.
Interesting. I wonder what happens if you run 1.0.6 and a due. Thanks for the update!
There’s no Duemilanove in v1.0.6? Due was their first board. Is your version maybe missing a file?
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