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anonymous /SerialPort_read.c
Created Sep 29, 2016

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/* hacked together from
https://github.com/xanthium-enterprises/Serial-Port-Programming-on-Linux/blob/master/USB2SERIAL_Read/Reciever%20(PC%20Side)/SerialPort_read.c
https://forum.arduino.cc/index.php?topic=288234.0
*/
/*====================================================================================================*/
/* Serial Port Programming in C (Serial Port Read) */
/* Non Cannonical mode */
/*----------------------------------------------------------------------------------------------------*/
/* Program reads a string from the serial port at 9600 bps 8N1 format */
/* Baudrate - 9600 */
/* Stop bits -1 */
/* No Parity */
/*----------------------------------------------------------------------------------------------------*/
/* Compiler/IDE : gcc 4.6.3 */
/* Library : */
/* Commands : gcc -o serialport_read serialport_read.c */
/* OS : Linux(x86) (Linux Mint 13 Maya)(Linux Kernel 3.x.x) */
/* Programmer : Rahul.S */
/* Date : 21-December-2014 */
/*====================================================================================================*/
/*====================================================================================================*/
/* www.xanthium.in */
/* Copyright (C) 2014 Rahul.S */
/*====================================================================================================*/
/*====================================================================================================*/
/* Running the executable */
/* ---------------------------------------------------------------------------------------------------*/
/* 1) Compile the serialport_read.c file using gcc on the terminal (without quotes) */
/* */
/* " gcc -o serialport_read serialport_read.c " */
/* */
/* 2) Linux will not allow you to access the serial port from user space,you have to be root.So use */
/* "sudo" command to execute the compiled binary as super user. */
/* */
/* "sudo ./serialport_read" */
/* */
/*====================================================================================================*/
/*====================================================================================================*/
/* Sellecting the Serial port Number on Linux */
/* ---------------------------------------------------------------------------------------------------*/
/* /dev/ttyUSBx - when using USB to Serial Converter, where x can be 0,1,2...etc */
/* /dev/ttySx - for PC hardware based Serial ports, where x can be 0,1,2...etc */
/*====================================================================================================*/
/*-------------------------------------------------------------*/
/* termios structure - /usr/include/asm-generic/termbits.h */
/* use "man termios" to get more info about termios structure */
/*-------------------------------------------------------------*/
#include <stdio.h>
#include <fcntl.h> /* File Control Definitions */
#include <termios.h> /* POSIX Terminal Control Definitions */
#include <unistd.h> /* UNIX Standard Definitions */
#include <errno.h> /* ERROR Number Definitions */
typedef enum { false, true } bool;
void main(void)
{
int fd;/*File Descriptor*/
printf("\n +----------------------------------+");
printf("\n | Serial Port Read |");
printf("\n +----------------------------------+");
/*------------------------------- Opening the Serial Port -------------------------------*/
/* Change /dev/ttyUSB0 to the one corresponding to your system */
fd = open("/dev/ttyUSB0",O_RDWR | O_NOCTTY); /* ttyUSB0 is the FT232 based USB2SERIAL Converter */
/* O_RDWR - Read/Write access to serial port */
/* O_NOCTTY - No terminal will control the process */
/* Open in blocking mode,read will wait */
if(fd == -1) /* Error Checking */
printf("\n Error! in Opening ttyUSB0 ");
else
printf("\n ttyUSB0 Opened Successfully ");
/*---------- Setting the Attributes of the serial port using termios structure --------- */
struct termios SerialPortSettings; /* Create the structure */
tcgetattr(fd, &SerialPortSettings); /* Get the current attributes of the Serial port */
/* Setting the Baud rate */
cfsetispeed(&SerialPortSettings,B9600); /* Set Read Speed as 9600 */
cfsetospeed(&SerialPortSettings,B9600); /* Set Write Speed as 9600 */
/* 8N1 Mode */
SerialPortSettings.c_cflag &= ~PARENB; /* Disables the Parity Enable bit(PARENB),So No Parity */
SerialPortSettings.c_cflag &= ~CSTOPB; /* CSTOPB = 2 Stop bits,here it is cleared so 1 Stop bit */
SerialPortSettings.c_cflag &= ~CSIZE; /* Clears the mask for setting the data size */
SerialPortSettings.c_cflag |= CS8; /* Set the data bits = 8 */
SerialPortSettings.c_cflag &= ~CRTSCTS; /* No Hardware flow Control */
SerialPortSettings.c_cflag |= CREAD | CLOCAL; /* Enable receiver,Ignore Modem Control lines */
SerialPortSettings.c_iflag &= ~(IXON | IXOFF | IXANY); /* Disable XON/XOFF flow control both i/p and o/p */
SerialPortSettings.c_iflag &= ~(ICANON | ECHO | ECHOE | ISIG); /* Non Cannonical mode */
SerialPortSettings.c_oflag &= ~OPOST;/*No Output Processing*/
/* Setting Time outs */
SerialPortSettings.c_cc[VMIN] = 10; /* Read at least 10 characters */
SerialPortSettings.c_cc[VTIME] = 0; /* Wait indefinetly */
if((tcsetattr(fd,TCSANOW,&SerialPortSettings)) != 0) /* Set the attributes to the termios structure*/
printf("\n ERROR ! in Setting attributes");
else
printf("\n BaudRate = 9600 \n StopBits = 1 \n Parity = none");
/*------------------------------- Read data from serial port -----------------------------*/
tcflush(fd, TCIFLUSH); /* Discards old data in the rx buffer */
char read_buffer[1024]; /* Buffer to store the data received */
int bytes_read = 0; /* Number of bytes read by the read() system call */
int i = 0;
char c;
int numChars = 32;
char receivedChars[numChars];
int ndx = 0;
char endMarker = '\n';
char rc;
bool newData = false;
while (1) {
while (read(fd, &c, 1) > 0 && newData == false) {
rc = c;
if (rc != endMarker) {
receivedChars[ndx] = rc;
ndx++;
if (ndx >= numChars) {
ndx = numChars - 1;
}
}
else {
receivedChars[ndx] = '\0'; // terminate the string
newData = true;
}
}
if (newData == true) {
//printf("This just in ...\n ");
for (i=0;i<ndx;i++) {
printf("%c",receivedChars[i]);
}
printf("\n");
ndx=0;
newData = false;
}
}
}
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