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//
// arduino-serial-lib -- simple library for reading/writing serial ports
//
// 2006-2013, Tod E. Kurt, http://todbot.com/blog/
//
#include "arduino-serial-lib.h"
#include <stdio.h> // Standard input/output definitions
#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
#include <string.h> // String function definitions
#include <sys/ioctl.h>
// uncomment this to debug reads
//#define SERIALPORTDEBUG
// takes the string name of the serial port (e.g. "/dev/tty.usbserial","COM1")
// and a baud rate (bps) and connects to that port at that speed and 8N1.
// opens the port in fully raw mode so you can send binary data.
// returns valid fd, or -1 on error
int serialport_init(const char* serialport, int baud)
{
struct termios toptions;
int fd;
//fd = open(serialport, O_RDWR | O_NOCTTY | O_NDELAY);
fd = open(serialport, O_RDWR | O_NONBLOCK );
if (fd == -1) {
perror("serialport_init: Unable to open port ");
return -1;
}
//int iflags = TIOCM_DTR;
//ioctl(fd, TIOCMBIS, &iflags); // turn on DTR
//ioctl(fd, TIOCMBIC, &iflags); // turn off DTR
if (tcgetattr(fd, &toptions) < 0) {
perror("serialport_init: Couldn't get term attributes");
return -1;
}
speed_t brate = baud; // let you override switch below if needed
switch(baud) {
case 4800: brate=B4800; break;
case 9600: brate=B9600; break;
#ifdef B14400
case 14400: brate=B14400; break;
#endif
case 19200: brate=B19200; break;
#ifdef B28800
case 28800: brate=B28800; break;
#endif
case 38400: brate=B38400; break;
case 57600: brate=B57600; break;
case 115200: brate=B115200; break;
}
cfsetispeed(&toptions, brate);
cfsetospeed(&toptions, brate);
// 8N1
toptions.c_cflag &= ~PARENB;
toptions.c_cflag &= ~CSTOPB;
toptions.c_cflag &= ~CSIZE;
toptions.c_cflag |= CS8;
// no flow control
toptions.c_cflag &= ~CRTSCTS;
//toptions.c_cflag &= ~HUPCL; // disable hang-up-on-close to avoid reset
toptions.c_cflag |= CREAD | CLOCAL; // turn on READ & ignore ctrl lines
toptions.c_iflag &= ~(IXON | IXOFF | IXANY); // turn off s/w flow ctrl
toptions.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); // make raw
toptions.c_oflag &= ~OPOST; // make raw
// see: http://unixwiz.net/techtips/termios-vmin-vtime.html
toptions.c_cc[VMIN] = 0;
toptions.c_cc[VTIME] = 0;
//toptions.c_cc[VTIME] = 20;
tcsetattr(fd, TCSANOW, &toptions);
if( tcsetattr(fd, TCSAFLUSH, &toptions) < 0) {
perror("init_serialport: Couldn't set term attributes");
return -1;
}
return fd;
}
//
int serialport_close( int fd )
{
return close( fd );
}
//
int serialport_writebyte( int fd, uint8_t b)
{
int n = write(fd,&b,1);
if( n!=1)
return -1;
return 0;
}
//
int serialport_write(int fd, const char* str)
{
int len = strlen(str);
int n = write(fd, str, len);
if( n!=len ) {
perror("serialport_write: couldn't write whole string\n");
return -1;
}
return 0;
}
//
int serialport_read_until(int fd, char* buf, char until, int buf_max, int timeout)
{
char b[1]; // read expects an array, so we give it a 1-byte array
int i=0;
do {
int n = read(fd, b, 1); // read a char at a time
if( n==-1) return -1; // couldn't read
if( n==0 ) {
usleep( 1 * 1000 ); // wait 1 msec try again
timeout--;
if( timeout==0 ) return -2;
continue;
}
#ifdef SERIALPORTDEBUG
printf("serialport_read_until: i=%d, n=%d b='%c'\n",i,n,b[0]); // debug
#endif
buf[i] = b[0];
i++;
} while( b[0] != until && i < buf_max && timeout>0 );
buf[i] = 0; // null terminate the string
return 0;
}
//
int serialport_flush(int fd)
{
sleep(2); //required to make flush work, for some reason
return tcflush(fd, TCIOFLUSH);
}