Hi,
I would exchange messages from Arduino to linux with a C program. The first step is read the serial port, so I wrote a conde on Arduino Diecimila that send me a sequence 0 1 2 3 and so on.
I would like print on video the sequence.
The problem is that using a debugger (in particular DDD) I am able to read the characters that arduino send to me but without a debugger I am not able to print them.
I read correctly the sequence using the linux command
tail -f < /dev/ttyUSB0
Follows Arduino and C codes. The C code comes from
http://todbot.com/blog/2006/12/06/arduino-serial-c-code-to-talk-to-arduino/
in particular
http://todbot.com/arduino/host/arduino-serial/arduino-serial.c
Thanks in Advance
Marco
================
Arduino Code
#define INIT_LOOP_DELAY 1000
#define INIT_SERIAL_BAUD_RATE 9600
int loop_delay;
int i=0;
void setup() {
loop_delay=INIT_LOOP_DELAY;
Serial.begin(INIT_SERIAL_BAUD_RATE);
Serial.flush();
}
void loop() {
if (loop_delay>0) delay(loop_delay);
Serial.println(String(i));
Serial.flush();
i++;
}
+++++++++++++++++++++++++
C Code
#include <stdio.h> /* Standard input/output definitions /
#include <stdlib.h>
#include <stdint.h> / Standard types /
#include <string.h> / String function 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 <sys/ioctl.h>
//#include <getopt.h>
#define BAUD_RATE B9600
#define STRING_SERIAL_PORT_LENGTH 256
#define STRING_BUF_LENGTH 256
#define SERIAL_PORT_DEVICE "/dev/ttyUSB0"
int serialport_read(int fd, char* c)
{
int n;
do {
n = read(fd, c, 1); // read a char at a time
if( n==-1) return -1; // couldn't read
if( n==0 ) {
usleep( 10 * 1000 ); // wait 10 msec try again
continue;
}
if ((*c=='\n') || (*c=='\r')) n=0;
} while( n<=0 );
return 0;
}
// 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;
//fprintf(stderr,"init_serialport: opening port %s @ %d bps\n",
// serialport,baud);
fd = open(serialport, O_RDWR | O_NOCTTY | O_NDELAY);
if (fd == -1) {
perror("init_serialport: Unable to open port ");
return -1;
}
if (tcgetattr(fd, &toptions) < 0) {
perror("init_serialport: 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 |= 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: Understanding UNIX termios VMIN and VTIME
toptions.c_cc[VMIN] = 0;
toptions.c_cc[VTIME] = 20;
if( tcsetattr(fd, TCSANOW, &toptions) < 0) {
perror("init_serialport: Couldn't set term attributes");
return -1;
}
return fd;
}
int main(int argc, char argv[])
{
int fd = 0;
char serial_port[STRING_SERIAL_PORT_LENGTH];
int baudrate = BAUD_RATE; // default
char c='';
int rc,n;
for (n=0;n<STRING_SERIAL_PORT_LENGTH;n++) serial_port[n]='0';
strcpy(serial_port,SERIAL_PORT_DEVICE);
fd = serialport_init(serial_port, baudrate);
if(fd==-1) {printf("Unable to open the device"); return -1;}
while (1) {
serialport_read(fd, &c);
printf("%c",c);
fflush(NULL);
}
} // end main
arduino_send_i.ino (306 Bytes)
test_01_receive.c (3.41 KB)