serialport.c

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/* -- Includes -- */
/* system libraries */
#include <stdio.h>   /* Standard input/output definitions */
#include <string.h>  /* String function definitions */
#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 */
/* project libraries */
#include "serialport.h"
#include "def.h"

/* -- Defines -- */

/* -- Functions -- */

serialport_t *serialport_open(const char *name)
{
    serialport_t *sps = (serialport_t *) malloc(sizeof(serialport_t)); // Serial port structure

    strcpy(sps->name, name); // Set name
    sps->descriptor = open(sps->name, O_RDWR | O_NOCTTY | O_NDELAY);

    if (sps->descriptor == s_ERROR)
    {
        // sCould not open the port.
        printf("serialport_open: Unable to open port - \"%s\".\n", sps->name);
    }
    else
    {
        fcntl(sps->descriptor, F_SETFL, 0);
    }

    return sps;
}

int serialport_close(serialport_t *sps)
{
    int res; // Result

    res = close(sps->descriptor);

    if (res == s_ERROR)
    {
        //Could not close the port.
        printf("serialport_close: Unable to close port - \"%s\".\n", sps->name);
    }

    // Free memory
    free(sps);

    return res;
}

int serialport_config(serialport_t *sps, unsigned int baud)
{
    int res; // Result
    struct termios options;
    speed_t baudrate;

    // Get the current options for the serial port
    tcgetattr(sps->descriptor, &options);

    // Update baudrate in structure
    sps->baudrate = baud;

    // Set the baud rate
    switch (sps->baudrate) {
        case 2400 :
            baudrate = B2400;
            break;
        case 4800 :
            baudrate = B4800;
            break;
        case 9600 :
            baudrate = B9600;
            break;
        case 19200 :
            baudrate = B19200;
            break;
        case 38400 :
            baudrate = B38400;
            break;
        case 57600 :
            baudrate = B57600;
            break;
        case 115200 :
            baudrate = B115200;
            break;
        default:
            printf("serialport_config: Invalid baud rate. Baud rate set to 9600.\n");
            baudrate = B9600;
            break;
    }
    cfsetispeed(&options, baudrate);
    cfsetospeed(&options, baudrate);

    //Enable the receiver and set local mode
    options.c_cflag |= (CLOCAL | CREAD);

    // Set 8 data bits / no parity bit / 1 stop bit
    options.c_cflag &= ~PARENB;
    options.c_cflag &= ~CSTOPB;
    options.c_cflag &= ~CSIZE;
    options.c_cflag |= CS8;

    // Local options
    //options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
    options.c_lflag = 0;

    // Input options
    //options.c_iflag &= ~(ICRNL);
    options.c_iflag = 0;

    // Output options
    //options.c_oflag &= ~OPOST;
    options.c_oflag = 0;

    // Set the new options for the serial port
    res = tcsetattr(sps->descriptor, TCSANOW, &options);

    // Error message
    if(res == s_ERROR)
    {
        printf("serialport_config: Could not apply new configuration.\n");
    }

    return res;
}


int serialport_write(serialport_t *sps, unsigned char *data, unsigned int bytes)
{
    // Write data
    return write(sps->descriptor, data, bytes);
}

int serialport_byte(serialport_t *sps, unsigned char byte)
{
    // Write one byte
    return write(sps->descriptor, &byte, 1);
}

int serialport_flush_input(serialport_t *sps)
{
    // Loacal variables
    char buffer[1000];

    // Uselessly read input buffer
    return read(sps->descriptor, &buffer, sizeof(buffer));
}

/*int serialport_read(serialport_t *sps, char *data, int bytes)
{
    char *bufptr; // Current char in buffer
    int  nbytes, bytes_left; // Number of bytes read

    bytes_left = bytes;

    // Read characters into buffer until we get a CR or NL
    bufptr = data;
    while ((nbytes = (int)read(sps->descriptor, bufptr, 1)) > 0)
    {
        bufptr += nbytes;
        bytes_left -= nbytes;
        if (bytes_left <= 0)
            break;
    }

    // Terminate the string with nul
    *bufptr = '\0';

    return 0;
}*/