我試圖從串口讀取,但總是得到0(零)字符回來。已經閱讀了「POSIX操作系統的串行編程指南」,但無法找出程序未等待(阻塞)的原因。 代碼:從串口讀取linux
#include <stdio.h> /* Standard input/output definitions */
#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 */
void main()
{
printf("Hello world\n");
int fd; /* File descriptor for the port */
int n;
int bytes;
char c;
char buffer[10];
char *bufptr;
struct termios options;
fd = open("/dev/ttyUSB0", O_RDWR | O_NOCTTY | O_NDELAY);
if (fd == -1) {
perror("open_port: Unable to open /dev/ttyUSB0 - ");
}
else {
fcntl(fd, F_SETFL, FNDELAY);
}
tcgetattr(fd, &options);
/* SEt Baud Rate */
cfsetispeed(&options, B9600);
cfsetospeed(&options, B9600);
//I don't know what this is exactly
options.c_cflag |= (CLOCAL | CREAD);
// Set the Charactor size
options.c_cflag &= ~CSIZE; /* Mask the character size bits */
options.c_cflag |= CS8; /* Select 8 data bits */
// Set parity - No Parity (8N1)
options.c_cflag &= ~PARENB;
options.c_cflag &= ~CSTOPB;
options.c_cflag &= ~CSIZE;
options.c_cflag |= CS8;
// Disable Hardware flowcontrol
// options.c_cflag &= ~CNEW_RTSCTS; -- not supported
// Enable Raw Input
options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
// Disable Software Flow control
options.c_iflag &= ~(IXON | IXOFF | IXANY);
// Chose raw (not processed) output
options.c_oflag &= ~OPOST;
if (tcsetattr(fd, TCSANOW, &options) == -1)
printf ("Error with tcsetattr = %s\n", strerror (errno));
else
printf ("%s\n", "tcsetattr succeed");
fcntl(fd, F_SETFL, 0);
// Write to the port
n = write(fd, "1", 1);
if (n < 0) {
fputs("write() of 1 bytes failed!\n", stderr);
}
// Read from the port
//fcntl(fd, F_SETFL, FNDELAY);
bytes = read(fd, &buffer, sizeof(buffer));
printf("number of bytes read is %d\n", bytes);
printf("%s\n", buffer);
//perror ("read error:");
close(fd);
}
這ecigs網站隻字未提串行通信/編程。 – josaphatv 2014-06-30 19:21:44
@josaphatv:現在是死鏈接。您可以嘗試[此方法](http://www.netzmafia.de/skripten/buecher/linuxhackz/Programme/Seriell/linux_serial_mini_howto.pdf)。 – jxh 2014-06-30 20:13:36