linux串口设备识别和信息收发
12 Aug 2013
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>
#include <asm-generic/ioctls.h>
#include <errno.h>
#define version "1.0"
#define FALSE -1
#define TRUE 0
int speed_attr[] = { B38400, B19200, B115200, B9600, B4800, B1200, B300,
B38400, B19200, B9600, B4800, B1200, B300, };
int name_attr[] = { 38400, 19200, 115200, 9600, 4800, 2400, 1200, 300, 38400,
19200, 9600, 4800, 2400, 1200, 300, };
int set_speed(int fd, int speed) {
int i;
int status;
struct termios Opt;
tcgetattr(fd, &Opt);
for(i = 0; i < sizeof(speed_attr) / sizeof(int); i++) {
if(speed == name_attr[i]) {
tcflush(fd, TCIOFLUSH);
cfsetispeed(&Opt, speed_attr[i]);
cfsetospeed(&Opt, speed_attr[i]);
status = tcsetattr(fd, TCSANOW, &Opt);
if(status != 0) {
perror("tcsetattr fd 1");
return (FALSE);
}
tcflush(fd, TCIOFLUSH);
return (TRUE);
}
}
return (FALSE);
}
int set_Parity(int fd, int databits, int stopbits, int parity) {
struct termios options;
if(tcgetattr(fd, &options) != 0) {
perror("setup serial parity 2");
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;
options.c_iflag &= ~INPCK;
break;
case 'o':
case 'O': options.c_cflag |= (PARODD | PARENB);
options.c_iflag |= INPCK;
break;
case 'e':
case 'E': options.c_cflag |= PARENB;
options.c_cflag &= ~PARODD;
options.c_iflag |= INPCK;
break;
case 's':
case 'S': 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);
}
if(parity != 'n')
options.c_iflag |= INPCK;
tcflush(fd, TCIFLUSH);
options.c_cc[VTIME] = 50;
options.c_cc[VMIN] = 0;
if(tcsetattr(fd, TCSANOW, &options) != 0) {
perror("Setup serials 3");
return (FALSE);
}
// options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
options.c_lflag &= ~(ICANON | ECHO | ISIG);
options.c_oflag &= ~OPOST;
// options.c_cflag |= (CLOCAL | CREAD);
return (TRUE);
}
int OpenDev(char *Dev) {
int fd = open(Dev, O_RDWR | O_NOCTTY); //O_NDELAY
if(-1 == fd) {
perror("Cannot Open Serial Port 4");
return -1;
} else {
fcntl(fd, F_SETFL, 0);
return fd;
}
}
int main(int argc, char **argv) {
int fd;
int nread;
int nwrite;
int status;
char *dev = argv[1];
fd = OpenDev(dev);
printf("Ver: %s, Port: %s, speed: %d\n", version, dev, atoi(argv[2]));
if(set_speed(fd, atoi(argv[2])) == FALSE) {
fprintf(stderr, "set_speed error\n");
close(fd);
exit(0);
}
if(set_Parity(fd, 8, 1, 'N') == FALSE) {
printf("Set Parity Error 5\n");
close(fd);
exit(0);
}
ioctl(fd, TIOCMGET, &status); // get hardware status
printf("status = %d\n", status); //测试串口电平
#if 0
while(1) {
ioctl(fd, TIOCMGET, &status); // get hardware status
printf("status = %d\n", status);
sleep(1);
}
#endif
#if 1
char buff[6] = {0};
while(1) {
nwrite = write(fd, "hello", 5);
if(nwrite < 0) {
fprintf(stderr, "write error\n");
}
tcflush(fd, TCIOFLUSH);
nread = read(fd, buff, 5);
buff[nread + 1] = '\0';
printf("\nret: %s\n", buff);
}
#endif
close(fd);
}