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Linux C Serial串口编程
1,Linux 下打开串口设备，信号模型 读写程序
2,串口读写的IO复用Select模型
3, Linux 下打开串口设备，读写程序
1,Linux 下打开串口设备，信号模型 读写程序
root@linux:/tmp/serial# cat main.c
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>
#include<termios.h>
#include<errno.h>
#define FALSE -1
#define TRUE 0
int speed_arr[] = { B38400, B19200, B9600, B4800, B2400, B1200, B300,B38400, B19200, B9600, B4800, B2400, B1200, B300, };
int name_arr[] = { 38400, 19200, 9600, 4800, 2400, 1200, 300, 38400, 19200, 9600, 4800, 2400, 1200, 300, };
void set_speed(int fd, int speed)
{
int i;
int status;
struct termios Opt;
tcgetattr(fd, &Opt);
for ( i= 0; i < sizeof(speed_arr) / sizeof(int); i++)
{
if (speed == name_arr[i])
{
tcflush(fd, TCIOFLUSH);
cfsetispeed(&Opt, speed_arr[i]);
cfsetospeed(&Opt, speed_arr[i]);
status = tcsetattr(fd, TCSANOW, &Opt);
if (status != 0)
{
perror("tcsetattr fd1");
return;
}
tcflush(fd,TCIOFLUSH);
}
}
}
int set_Parity(int fd,int databits,int stopbits,int parity)
{
struct termios options;
if ( tcgetattr( fd,&options) != 0)
{
perror("SetupSerial 1");
return(FALSE);
}
options.c_cflag &= ~CSIZE;
switch (databits)
{
case 7:
options.c_cflag |= CS7;
break;
case 8:
options.c_cflag |= CS8;
break;
default:
fprintf(stderr,"Unsupported data size\n"); return (FALSE);
}
switch (parity)
{
case ‘n‘:
case ‘N‘:
options.c_cflag &= ~PARENB; /* Clear parity enable */
options.c_iflag &= ~INPCK; /* Enable parity checking */
break;
case ‘o‘:
case ‘O‘:
options.c_cflag |= (PARODD | PARENB);
options.c_iflag |= INPCK; /* Disnable parity checking */
break;
case ‘e‘:
case ‘E‘:
options.c_cflag |= PARENB; /* Enable parity */
options.c_cflag &= ~PARODD;
options.c_iflag |= INPCK; /* Disnable parity checking */
break;
case ‘S‘:
case ‘s‘: /*as no parity*/
options.c_cflag &= ~PARENB;
options.c_cflag &= ~CSTOPB;break;
default:
fprintf(stderr,"Unsupported parity\n");
return (FALSE);
}
switch (stopbits)
{
case 1:
options.c_cflag &= ~CSTOPB;
break;
case 2:
options.c_cflag |= CSTOPB;
break;
default:
fprintf(stderr,"Unsupported stop bits\n");
return (FALSE);
}
/* Set input parity option */
if (parity != ‘n‘)
options.c_iflag |= INPCK;
tcflush(fd,TCIFLUSH);
options.c_cc[VTIME] = 150;
options.c_cc[VMIN] = 0; /* Update the options and do it NOW */
if (tcsetattr(fd,TCSANOW,&options) != 0)
{
perror("SetupSerial 3");
return (FALSE);
}
return (TRUE);
}
int main()
{
int fd;
fd = open("/dev/ttyUSB0",O_RDWR);
if(fd == -1)
{
perror("serialport error\n");
}
else
{
printf("open ");
printf("%s",ttyname(fd));
printf(" succesfully\n");
}
set_speed(fd,115200);
if (set_Parity(fd,8,1,‘N‘) == FALSE) {
printf("Set Parity Error\n");
exit (0);
}
char buf[] = "1234567890123456789012345678901234567890";
int n= write(fd,buf,strlen(buf));
printf("字符串实际长度%zd \n", strlen(buf));
printf("成功写入%d \n", n);
char buff[512];
int nread;
while(1)
{
if((nread = read(fd, buff, 512))>0)
{
printf("Len: %d:",nread);
buff[nread] = ‘\0‘;
printf("%s \n",buff);
}
}
close(fd);
return 0;
}
root@linux:/tmp/serial# gcc -Wall main.c && ./a.out
open /dev/ttyUSB0 succesfully
字符串实际长度40
成功写入40
Len: 32:12345678901234567890123456789012
Len: 8:34567890
^C
root@linux:/tmp/serial#2,串口读写的IO复用Select模型
root@linux:/tmp/serial# cat main.c
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<sys/signal.h>
#include<fcntl.h>
#include<termios.h>
#include<errno.h>
#define FALSE -1
#define TRUE 0
#define flag 1
#define noflag 0
int wait_flag = noflag;
int STOP = 0;
int res;
int speed_arr[] = { B38400, B19200, B9600, B4800, B2400, B1200, B300, B38400, B19200, B9600, B4800, B2400, B1200, B300, };
int name_arr[] = { 38400, 19200, 9600, 4800, 2400, 1200, 300, 38400, 19200, 9600, 4800, 2400, 1200, 300, };
void set_speed (int fd, int speed)
{
int i;
int status;
struct termios Opt;
tcgetattr (fd, &Opt);
for (i = 0; i < sizeof (speed_arr) / sizeof (int); i++)
{
if (speed == name_arr[i])
{
tcflush (fd, TCIOFLUSH);
cfsetispeed (&Opt, speed_arr[i]);
cfsetospeed (&Opt, speed_arr[i]);
status = tcsetattr (fd, TCSANOW, &Opt);
if (status != 0)
{
perror ("tcsetattr fd1");
return;
}
tcflush (fd, TCIOFLUSH);
}
}
}
int set_Parity (int fd, int databits, int stopbits, int parity)
{
struct termios options;
if (tcgetattr (fd, &options) != 0)
{
perror ("SetupSerial 1");
return (FALSE);
}
options.c_cflag &= ~CSIZE;
switch (databits)
{
case 7:
options.c_cflag |= CS7;
break;
case 8:
options.c_cflag |= CS8;
break;
default:
fprintf (stderr, "Unsupported data size\n");
return (FALSE);
}
switch (parity)
{
case ‘n‘:
case ‘N‘:
options.c_cflag &= ~PARENB; /* Clear parity enable */
options.c_iflag &= ~INPCK; /* Enable parity checking */
break;
case ‘o‘:
case ‘O‘:
options.c_cflag |= (PARODD | PARENB);
options.c_iflag |= INPCK; /* Disnable parity checking */
break;
case ‘e‘:
case ‘E‘:
options.c_cflag |= PARENB; /* Enable parity */
options.c_cflag &= ~PARODD;
options.c_iflag |= INPCK; /* Disnable parity checking */
break;
case ‘S‘:
case ‘s‘: /*as no parity */
options.c_cflag &= ~PARENB;
options.c_cflag &= ~CSTOPB;
break;
default:
fprintf (stderr, "Unsupported parity\n");
return (FALSE);
}
switch (stopbits)
{
case 1:
options.c_cflag &= ~CSTOPB;
break;
case 2:
options.c_cflag |= CSTOPB;
break;
default:
fprintf (stderr, "Unsupported stop bits\n");
return (FALSE);
}
/* Set input parity option */
if (parity != ‘n‘)
options.c_iflag |= INPCK;
tcflush (fd, TCIFLUSH);
options.c_cc[VTIME] = 150;
options.c_cc[VMIN] = 0; /* Update the options and do it NOW */
if (tcsetattr (fd, TCSANOW, &options) != 0)
{
perror ("SetupSerial 3");
return (FALSE);
}
return (TRUE);
}
void signal_handler_IO (int status)
{
printf ("received SIGIO signale.\n");
wait_flag = noflag;
}
int main ()
{
int fd;
struct sigaction saio;
fd = open ("/dev/ttyUSB0", O_RDWR);
if (fd == -1)
{
perror ("serialport error\n");
}
else
{
printf ("open ");
printf ("%s", ttyname (fd));
printf (" succesfully\n");
}
saio.sa_handler = signal_handler_IO;
sigemptyset (&saio.sa_mask);
saio.sa_flags = 0;
saio.sa_restorer = NULL;
sigaction (SIGIO, &saio, NULL);
//allow the process to receive SIGIO
fcntl (fd, F_SETOWN, getpid ());
//make the file descriptor asynchronous
fcntl (fd, F_SETFL, FASYNC);
set_speed (fd, 115200);
if (set_Parity (fd, 8, 1, ‘N‘) == FALSE)
{
printf ("Set Parity Error\n");
exit (0);
}
char str[] = "1234567890123456789012345678901234567890";
int n= write(fd,str,strlen(str));
printf("字符串实际长度%zd \n", strlen(str));
printf("成功写入%d \n", n);
char buf[255];
while (STOP == 0)
{
usleep (100000);
/* after receving SIGIO ,wait_flag = FALSE,input is availabe and can be read */
if (wait_flag == 0)
{
memset (buf, 0, sizeof(buf));
res = read (fd, buf, 255);
printf ("nread=%d,%s\n", res, buf);
// if (res ==1)
// STOP = 1; /*stop loop if only a CR was input */
wait_flag = flag; /*wait for new input */
}
}
close (fd);
return 0;
}
root@linux:/tmp/serial# gcc -Wall main.c && ./a.out
open /dev/ttyUSB0 succesfully
字符串实际长度40
成功写入40
received SIGIO signale.
received SIGIO signale.
nread=32,12345678901234567890123456789012
received SIGIO signale.
nread=8,34567890
^C
root@linux:/tmp/serial#3, Linux 下打开串口设备，读写程序
root@linux:/tmp/serial# cat main.c
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<sys/signal.h>
#include<fcntl.h>
#include<termios.h>
#include<errno.h>
#define FALSE -1
#define TRUE 0
#define flag 1
#define noflag 0
int wait_flag = noflag;
int STOP = 0;
int res;
int speed_arr[] = { B38400, B19200, B9600, B4800, B2400, B1200, B300, B38400, B19200, B9600, B4800, B2400, B1200, B300, };
int name_arr[] = { 38400, 19200, 9600, 4800, 2400, 1200, 300, 38400, 19200, 9600, 4800, 2400, 1200, 300, };
void set_speed (int fd, int speed)
{
int i;
int status;
struct termios Opt;
tcgetattr (fd, &Opt);
for (i = 0; i < sizeof (speed_arr) / sizeof (int); i++)
{
if (speed == name_arr[i])
{
tcflush (fd, TCIOFLUSH);
cfsetispeed (&Opt, speed_arr[i]);
cfsetospeed (&Opt, speed_arr[i]);
status = tcsetattr (fd, TCSANOW, &Opt);
if (status != 0)
{
perror ("tcsetattr fd1");
return;
}
tcflush (fd, TCIOFLUSH);
}
}
}
int set_Parity (int fd, int databits, int stopbits, int parity)
{
struct termios options;
if (tcgetattr (fd, &options) != 0)
{
perror ("SetupSerial 1");
return (FALSE);
}
options.c_cflag &= ~CSIZE;
switch (databits)
{
case 7:
options.c_cflag |= CS7;
break;
case 8:
options.c_cflag |= CS8;
break;
default:
fprintf (stderr, "Unsupported data size\n");
return (FALSE);
}
switch (parity)
{
case ‘n‘:
case ‘N‘:
options.c_cflag &= ~PARENB; /* Clear parity enable */
options.c_iflag &= ~INPCK; /* Enable parity checking */
break;
case ‘o‘:
case ‘O‘:
options.c_cflag |= (PARODD | PARENB);
options.c_iflag |= INPCK; /* Disnable parity checking */
break;
case ‘e‘:
case ‘E‘:
options.c_cflag |= PARENB; /* Enable parity */
options.c_cflag &= ~PARODD;
options.c_iflag |= INPCK; /* Disnable parity checking */
break;
case ‘S‘:
case ‘s‘: /*as no parity */
options.c_cflag &= ~PARENB;
options.c_cflag &= ~CSTOPB;
break;
default:
fprintf (stderr, "Unsupported parity\n");
return (FALSE);
}
switch (stopbits)
{
case 1:
options.c_cflag &= ~CSTOPB;
break;
case 2:
options.c_cflag |= CSTOPB;
break;
default:
fprintf (stderr, "Unsupported stop bits\n");
return (FALSE);
}
/* Set input parity option */
if (parity != ‘n‘)
options.c_iflag |= INPCK;
tcflush (fd, TCIFLUSH);
options.c_cc[VTIME] = 150;
options.c_cc[VMIN] = 0; /* Update the options and do it NOW */
if (tcsetattr (fd, TCSANOW, &options) != 0)
{
perror ("SetupSerial 3");
return (FALSE);
}
return (TRUE);
}
void signal_handler_IO (int status)
{
printf ("received SIGIO signale.\n");
wait_flag = noflag;
}
int main ()
{
int fd;
fd = open ("/dev/ttyUSB0", O_RDWR);
if (fd == -1)
{
perror ("serialport error\n");
}
else
{
printf ("open ");
printf ("%s", ttyname (fd));
printf (" succesfully\n");
}
set_speed (fd, 115200);
if (set_Parity (fd, 8, 1, ‘N‘) == FALSE)
{
printf ("Set Parity Error\n");
exit (0);
}
char str[] = "1234567890123456789012345678901234567890";
int n= write(fd,str,strlen(str));
printf("字符串实际长度%zd \n", strlen(str));
printf("成功写入%d \n", n);
char buf[255];
fd_set rd;
int nread = 0;
while(1)
{
FD_ZERO(&rd);
FD_SET(fd, &rd);
while(FD_ISSET(fd, &rd))
{
if(select(fd+1, &rd, NULL,NULL,NULL) < 0)
{
perror("select error\n");
}
else
{
while((nread = read(fd, buf, sizeof(buf))) > 0)
{
printf("nread= %02d,%s\n",nread, buf);
memset(buf, 0 , sizeof(buf));
}
}
}
}
close (fd);
return 0;
}
root@linux:/tmp/serial# gcc -Wall main.c && ./a.out
open /dev/ttyUSB0 succesfully
字符串实际长度40
成功写入40
nread= 32,12345678901234567890123456789012
nread= 08,34567890本文出自 “魂斗罗” 博客，请务必保留此出处http://990487026.blog.51cto.com/10133282/1901695
Linux C Serial串口编程
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