Using C code in s-functions

Hi everyone;

I have a c code which need to be used in simulink block. The c code is working well, but I could not build a proper s-function with it. There are several errors;

       1- In my c code there is a function other than main, How it should be implement in s function?
       2- There is a struct which occurs a trouble also.
       3- Does normal c syntax problem for matlab 'int' cause a error
       4- Although I gave an initial value for my variables s function builder always wants a Ivalue error

If you help me I appreciate, I could not find a proper source yet. Thank you

Answer 1

[Kaustubha Govind]

1. It depends on where this function needs to be called from. Can you elaborate on how the function needs to be used?
2. For structure inputs/outputs, you need to use bus signals.
3. I don't know that you see errors using 'int' - could you please paste the offending code and the error message.
4. Again, please paste the offending code and the error message.

[Ufuk Irmak]

#include <fcntl.h>
#include <errno.h>  
#include <signal.h>
#include <stdlib.h>
#include <termios.h> 
#include <unistd.h> 
#include <stdio.h> 
#include <string.h>

int serial_port_open(void);

static const char *PORT_NAME = "/dev/ttyO2";  // for default RS232 console at BB

int serial_port;
struct termios options_original;

int main (void)
{

     serial_port_open();

  
  int temp[] = {1,2};

  
  int a = sizeof(temp);

  write(serial_port, &temp, a);

  printf("%d\n",a);

  return 0;

}

int serial_port_open(void)
{
  struct termios options;

    serial_port = open(PORT_NAME, O_RDWR | O_NONBLOCK);

    if (serial_port != -1)
    {
    
      tcgetattr(serial_port,&options_original);
       tcgetattr(serial_port, &options);
      cfsetispeed(&options, B115200);
      cfsetospeed(&options, B115200);
      options.c_cflag |= (CLOCAL | CREAD | CRTSCTS | CS8);
      options.c_cflag &= (~PARENB & ~CSTOPB & ~CSIZE);
      options.c_lflag |= ICANON;
      options.c_iflag |= (IGNPAR |ICRNL);
      if (tcsetattr(serial_port, TCSANOW, &options)!=0)
      {
        printf("error serial port could not open!!!");
        return (-1);
      }
    }
    else
    {

    end

This code and errors which I got, I made several changes to decrease errors but new ones occured while I was doing that. The main purpose of this code is serial port handling and write. I use it in Beagleboard xm with S-functions. I want my matlab algorithm to work in Beagleboard and use serial port. Thank you for your interest.

[Kaustubha Govind]

Ufuk: At this point, your code is not even in an S-function, but is a regular C-executable with a main(). You probably need to get help from a more C/C++ forum than a MATLAB/Simulink forum. It's hard for me to tell, because it's not clear where symbols like CLOCAL, and types like 'termios' are being defined. Please follow basic C rules and make sure that you can compile your code outside of MATLAB.

Answer 2

[Dan]

You declare to include some header files

#include fcntl.h #include errno.h #include signal.h #include stdlib.h #include termios.h #include unistd.h #include stdio.h #include string.h

But the Matlab/Simlink coder may fail to find these files. Consequently, when your codes refer to the variables predefined in these header, the compiler reports errors. Please see the Simulink 7 Writing S-Functions reference, you may need to define LIB_PATH, etc to have Matlab/Simulink to know where there header files are

Answer 3

[Ahmet Tuna]

Hey,

I have the same problem. I have C code, in this code i am communicating with serial port. The C code is working. I have made the changes for mexFunction. When i gave the command mex serialPort.c it also works and compiles. But when i use the function the serial does not open. Do you have a solution?

best regards