Thread: Wirte and read serial port

You are using "void main" - Have you seen Salem's avatar? Change it to "int main" and return 0 at the end.

Originally Posted by jimblumberg

Where did I say anything like that. You need to re-read my last post. You need to escape this escape character.

Jim

Hello Jim, now i have a big problem, hope you'll bear with me to solve this.

1.) i'm sending hex command to my device/port like the code below:

Code:

result2 = write(mainfd,"\xF5\x23\x00\x00\x00\x00\x23\xF5",8);
 if ( result2 == -1 ) { perror("error: write"); }
 if ( result2 != 8 ) { fprintf(stderr,"error in write, result = %d\n", result2); }

2.) Above example is a hex command which have length of 8byte. The problem now is i have a .txt file which content below data:

\xf5\x00\x00\x00\x17\x0a\x16\x01\x61\x0e\x1d\x1a\x 01\x16\x95\x00\xc1\x1f\x26\x44\xa1\x1f\x88\x95\xe1 \x24\x1f\xda\x41\x26\x92\x00\x01\x35\x90\x00\x81\x 43\x22\x44\x21\x53\x16\x01\x61\x57\xa2\x44\x81\x65 \x92\xab\x01\x69\x89\xa6\xa1\x79\x29\xc8\x01\x7d\x 2c\x09\x01\x7e\x8e\x22\xe1\x82\xa5\x47\x21\x84\xab \x02\x01\x8a\xac\x2b\x21\x09\x1c\x03\x82\x2b\x8f\x 97\x82\x2e\x1a\x59\xc2\x6e\x95\x40\x02\x01\x00\x00 \x01\x01\x01\x01\x01\x01\x00\x00\x00\x00\x00\x00\x 00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00 \x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x 00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00 \x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x 00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00 \x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x 00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x04\xf5 <==(207 byte data)

==>In the same c file where i need to send the hex command, i called the above data and put it into an array. The problem now is i need to combine the data in that particular array with the hex command which i gave in (1) before i send it to the port. How can i do that? Below is my current code which have error:

Code:

/* Include files */
#include<stdio.h>
#include<string.h>
#include <stdlib.h>
//------------------------------------------------------------//
 #include <unistd.h>  /* UNIX standard function definitions */
 #include <fcntl.h>   /* File control definitions */
 #include <errno.h>   /* Error number definitions */
 #include <termios.h> /* POSIX terminal control definitions */
//------------------------------------------------------------//

#define VIN_FILE 2

/* Constants to define position in file */
#define BEGIN 0
#define CURRENT 1 


#define VIN_RECLEN 30

FILE *fpVin;

/* Function declarations */

int fnOpenFile ( int iFile );
int fnReadFile ( char acLine[], int iFile, int ipos);

int fnReadFile ( char acLine[], int iFile, int ipos)
{
    if( iFile==VIN_FILE)
    {
        if (ipos == BEGIN) {
            if (fseek(fpVin, 0L, SEEK_SET)) {
                return 1;
            }
        }
        if ( NULL == fgets (acLine, VIN_RECLEN, fpVin) ) {
            return 1;
        }
    }
    return 0;
}

int fnOpenFile ( int iFile )
{
    char acFileName[20];



   if(iFile==VIN_FILE)
   {
        strcpy (acFileName, "eigen_from_database.txt");
        fpVin = fopen(acFileName, "r+");
        if (NULL == fpVin) {
            return 1;
        }        
   }
    return 0;
}

 int open_port(void)
 {
   int fd;                                   /* File descriptor for the port */

   fd = open("/dev/ttyUSB0", O_RDWR | O_NOCTTY | O_NDELAY);

   if (fd < 0) {                                              /* Could not open the port */
     fprintf(stderr, "open_port: Unable to open /dev/ttyUSB0 - %s\n",
             strerror(errno));
   }

   return (fd);
 }


int main()
{
        int iRet,count, int_1, int_2, mainfd=0, i;
    /*data row*/
    char acVinRecord[900], cnt, result2, temp_final[800];
    unsigned char result,chout;
    struct termios options;
        FILE *fp;

//===========================Open port and set configuration=========================================//
mainfd = open_port();

 fcntl(mainfd, F_SETFL, FNDELAY);                  /* Configure port reading */
                                     /* Get the current options for the port */
 tcgetattr(mainfd, &options);
 cfsetispeed(&options, B19200);                 /* Set the baud rates to 19200 */
 cfsetospeed(&options, B19200);
    
                                   /* Enable the receiver and set local mode */
 options.c_cflag |= (CLOCAL | CREAD);
 options.c_cflag &= ~PARENB; /* Mask the character size to 8 bits, no parity */
 options.c_cflag &= ~CSTOPB;
 options.c_cflag &= ~CSIZE;
 options.c_cflag |=  CS8;                              /* Select 8 data bits */
 options.c_cflag &= ~CRTSCTS;               /* Disable hardware flow control */  
 
                                 /* Enable data to be processed as raw input */
 options.c_lflag &= ~(ICANON | ECHO | ISIG);
       
                                        /* Set the new options for the port */
 
//============Take the 207 byte data and put it in an array (temp_string)============================//
    /* Open the Policy file to start with */
    iRet = fnOpenFile (VIN_FILE);

    /* Unable to open file results ? */
    if (iRet != 0) {
        printf ("\t\t\tERROR: Unable to open the file results\n");
        
        exit (1);
    }

    /* Read the first record */
    iRet = fnReadFile (acVinRecord, VIN_FILE, BEGIN);
    count=0;
    /* Read further till the last record */
    while (0 == iRet) 
       {
    count=count+1;
    int_1 = 0; int_2= 0;
    switch (count)
    {
    case 1:

    for (int_1=0, int_2=0; int_1<29,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 2:
    
    for (int_1=29, int_2=0; int_1<58,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    //temp_final[58]= '\0';
    break;

    case 3:
    
    for (int_1=58, int_2=0; int_1<87,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }

    break;

    case 4:
    
    for (int_1=87, int_2=0; int_1<116,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 5:
    
    for (int_1=116, int_2=0; int_1<145,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }

    break;
    
    case 6:
    
    for (int_1=145, int_2=0; int_1<174,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    
    break;

    case 7:
    
    for (int_1=174, int_2=0; int_1<203,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 8:
    
    for (int_1=203, int_2=0; int_1<232,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 9:
    
    for (int_1=232, int_2=0; int_1<261,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 10:
    
    for (int_1=261, int_2=0; int_1<290,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 11:
    
    for (int_1=290, int_2=0; int_1<319,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 12:
    
    for (int_1=319, int_2=0; int_1<348,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 13:
    
    for (int_1=348, int_2=0; int_1<377,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 14:
    
    for (int_1=377, int_2=0; int_1<406,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 15:
    
    for (int_1=406, int_2=0; int_1<435,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 16:
    
    for (int_1=435, int_2=0; int_1<464,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 17:
    
    for (int_1=464, int_2=0; int_1<493,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }

    break;

    case 18:
    
    for (int_1=493, int_2=0; int_1<522,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 19:
    
    for (int_1=522, int_2=0; int_1<551,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 20:
    
    for (int_1=551, int_2=0; int_1<580,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 21:
    
    for (int_1=580, int_2=0; int_1<609,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 22:
    
    for (int_1=609, int_2=0; int_1<638,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;
    
    case 23:
    
    for (int_1=638, int_2=0; int_1<667,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 24:
    
    for (int_1=667, int_2=0; int_1<696,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 25:
    
    for (int_1=696, int_2=0; int_1<725,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;
    
    case 26:
    
    for (int_1=725, int_2=0; int_1<754,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 27:
    
    for (int_1=754, int_2=0; int_1<783,int_2<29;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    break;

    case 28:
    
    for (int_1=783, int_2=0; int_1<797,int_2<14;int_1++,int_2++)
    {
        temp_final[int_1] = acVinRecord[int_2];
    }
    temp_final[797]= '\0';
    break;
    }

        iRet = fnReadFile (acVinRecord, VIN_FILE, CURRENT);
    }
    
    printf("%s\n",temp_final);

//====This is where i need to combine data in array with the existing hex command==========//
    tcsetattr(mainfd, TCSANOW, &options);
 
     tcflush(mainfd, TCIOFLUSH); // Clear both the input and output buffers.

    result2 = write(mainfd,"\xF5\x41\x00\x00\x00\x00\x41\xF5\xF5\x00\x01\x01\\%s\",211,temp_final);
     if ( result2 == -1 ) { perror("error: write"); }
     if ( result2 != 8 ) { fprintf(stderr,"error in write, result = %d\n", result2); }
    
    close(mainfd);        /* Close the serial port */
//==========================================================================================//
    
}

p/s: just ignore any unuseful function in the code. abit mess.

Originally Posted by jimblumberg

I really don't understand your problem. But I do see a couple of problems:

Code:

    char acFileName[20];
 
 
 
   if(iFile==VIN_FILE)
   {
        strcpy (acFileName, "eigen_from_database.txt");
        fpVin = fopen(acFileName, "r+");

In the above snippet you have an out of bounds array access. You allocated 20 bytes to your array, how many characters are in that string constant? Why are you even doing the strcpy()? Why not just use the string constant for the fopen parameter?


Next: What's with all the case statements?

Are you sure your reading your file correctly? Have you printed out the values of that array to insure it is correct?

Please post the exact contents of your input file.


Jim

Yes Jim, i printed out the correct data from the .txt file. The problem is how to combine the hex data in array(temp_final) with the existing hex data in here ==> "result2 = write(mainfd,"\xF5\x23\x00\x00\x00\x00\x23\xF5",8) ;"

I've posted the content of the input file #69

> 2.) Above example is a hex command which have length of 8byte. The problem now is i have a .txt file which content below data:
> \xf5\x00\x00\x00\x17\x0a
When you're writing bytes using \xnn in C code, then the compiler is responsible for stripping off the \x and interpreting nn as a single byte.

When you're reading from a file, it's your responsibility to read 4 chars, strip off the \x and assign the conversion of "nn" to nn.

Code:

result2 = write(mainfd,get,8);

Your program will only send the first 8 characters of that string and this is
\xF5\x00
you need to find a way to convert the string \xF5\x01\x00\x00\x00\x00\x01\xF5
into an array of unsigned characters that contains

Code:

unsigned char buff[] = { 245, 1, 0, 0,  0, 0, 1, 245 };

And note. there isn't anything like hex data. There exists only hex representation of data
Kurt