Serial data transfer problem

Projects Programming
1

I'm reading OBD2 data and sending via serial to another processor.
The received data is stripped of start and end markers and is formatted with a single character identifier, comma, and int or long. This is what a debug serial print of receivedChars looks like:
r,0
k,0
r,0
k,0
r,0
k,0
r,0
k,0
o,14
r,0
d,248924
c,14

I'm using scanf and switch/case to put the data into variables.

It doesn't work as expected and I'm clueless when it comes to string conversion. Any help would be appreciated.

I can't post all the code for both processors, it's a lot, and everything else works.


  char mark;
  unsigned long data;

    sscanf(receivedChars, "%c,%u", &mark, &data);

    switch (mark) {
      case 'f':
        fuel = data;
        break;
      case 'r':
        rpm = data;
        break;
      case 'k':
        kph = data;
        break;
      case 'd':
        odom = data;
        break;
      case 'c':
        cool = data;
        break;
      case 'o':
        oil = data;
        break;
    }
2

You'll have to say more. I saw nothing wrong.

This

char receivedChars[] = "k,42";

//...

  sscanf(receivedChars, "%c,%u", &mark, &data);

works fine. So I wonder where receivedChars comes from and what is actually in it when you hit the sscanf().


I did have to fix it for the one case where you exploit a long variable 
  sscanf(receivedChars, "%c,%lu", &mark, &data);

a tip off from another compiler.

Got warnings turned up in the IDE? You may have missed

/var/folders/gz/t92bgl156gdf2066kn0xpc7w0000gq/T/arduino_modified_sketch_290204/sketch_jul09a.ino: In function 'void setup()':
/var/folders/gz/t92bgl156gdf2066kn0xpc7w0000gq/T/arduino_modified_sketch_290204/sketch_jul09a.ino:15:46: warning: format '%u' expects argument of type 'unsigned int*', but argument 4 has type 'long unsigned int*' [-Wformat=]
   sscanf(receivedChars, "%c,%u", &mark, &data);

HTH

a7

3

what are the processors?
post a schematic showing the wiring including ground and power connections?

4

Changed sscanf(receivedChars, "%c,%u", &mark, &data);
to
sscanf(receivedChars, "%c,%lu", &mark, &data);

And all good. Thanks for the replies.

5

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