怎样在unix下用c编写串口通信？

[ricsson]

谁有这方面的资料？？

[luxc1972]

很简单，给你一段源代码，使用举例： ngComFd = InitCom("/dev/tty1a", O_RDONLY);
读写时调用read(), write()就可以了。

int InitCom(strTtyName, nOpenFlag)
char *strTtyName;
int nOpenFlag;
{
int nFd;
char temp[50];
struct termio termNewtty;

if ((nFd = open(strTtyName, nOpenFlag)) == -1)
{
sprintf(temp, "Open %s error !\n", strTtyName);
perror(temp);
return (-1);
}

if (ioctl(nFd, TCGETA, &termNewtty) == -1)
{
sprintf(temp, "%s TCGETA is error !\n", strTtyName);
perror(temp);
close(nFd);
return (-1);
}

termNewtty.c_iflag = IGNBRK;
termNewtty.c_oflag = 0;
switch (atoi(strsBaudRate))
{
case 1200:
termNewtty.c_cflag=CLOCAL|HUPCL|CREAD|CS8|B1200;
break;
case 2400:
termNewtty.c_cflag=CLOCAL|HUPCL|CREAD|CS8|B2400;
break;
case 4800:
termNewtty.c_cflag=CLOCAL|HUPCL|CREAD|CS8|B4800;
break;
case 9600:
termNewtty.c_cflag=CLOCAL|HUPCL|CREAD|CS8|B9600;
break;
case 19200:
termNewtty.c_cflag=CLOCAL|HUPCL|CREAD|CS8|B19200;
break;
case 38400:
termNewtty.c_cflag=CLOCAL|HUPCL|CREAD|CS8|B38400;
break;
case 115200:
termNewtty.c_cflag=CLOCAL|HUPCL|CREAD|CS8|B115200;
break;
default:
termNewtty.c_cflag=CLOCAL|HUPCL|CREAD|CS8|B2400;
break;
}

termNewtty.c_lflag = 0;
termNewtty.c_cc[VMIN] = 1;
if (ioctl(nFd, TCSETA, &termNewtty) == -1)
{
sprintf(temp, "%s TCSETA is error !\n", strTtyName);
perror(temp);
close(nFd);
return (-1);
}

return(nFd);
}

[z_sky]

网上可以找到很多，这是我以前程序的部分代码，仅供参考。

static int fdmodem=-1;

void dummyalrm(int dummy)
{
dummy = 0;
longjmp(jmpbuf, 1);
}

int com_open(int n)
{
char s[255];
int modem;
struct stat status;

/* Create the full name of the device */
sprintf(s, "/dev/ttyS%d", n);

/* Opening the device */
if (setjmp(jmpbuf) == 0)
{
modem = -1;
signal(SIGALRM, dummyalrm);
alarm(2);
if ((modem = open(s, O_RDWR|O_NOCTTY|O_NONBLOCK)) == -1) return EOPEN;
}
alarm(0);
signal(SIGALRM, SIG_IGN);

/*Get device's status */
if (fstat(modem, &status) == -1)
{
close(modem);
return ESTAT;
}

/* Checking if device is charachter device */
if (!S_ISCHR(status.st_mode))
{
close(modem);
return ECHAR;
}

/* Get device's flags using termios */
if (tcgetattr(modem, &term) == -1)
{
close(modem);
return EGETA;
}

/* Save the flags */
memcpy(&saveterm, &term, sizeof(struct termios));

/* Enter raw mode */

term.c_iflag &= ~(IGNBRK | IGNCR | INLCR | ICRNL | IUCLC | IXANY |
IXON | IXOFF | INPCK | ISTRIP);
term.c_iflag |= BRKINT | IGNPAR;
term.c_oflag &= ~OPOST;
term.c_lflag = ~(ICANON | ISIG | ECHO | ECHONL | ECHOE | ECHOK);
term.c_cflag |= CS8 | CREAD | HUPCL | CRTSCTS;

/* Set the baud */
cfsetospeed(&term, B9600);
cfsetispeed(&term, B9600);

/* Set the attributes */
tcsetattr(modem, TCSANOW, &term);

return modem;
}

int com_close()
{
close(fdmodem);
fdmodem = -1;
return 0;
}


/* A function that checks if there is any input from the modem */
int com_charwaiting()
{
fd_set set;
struct timeval timeout;

timeout.tv_sec = 0;
timeout.tv_usec = MSWAIT;

FD_ZERO(&set);
FD_SET(fdmodem, &set);
if (select(fdmodem+1, &set, NULL, NULL, &timeout) > 0)
{
if (FD_ISSET(fdmodem, &set)) return TRUE;
}
return FALSE;
}

/* This function checks if a write can be done */
int com_canwrite()
{
fd_set set;
struct timeval timeout;

timeout.tv_sec = 0;
timeout.tv_usec = MSWAIT;

FD_ZERO(&set);
FD_SET(fdmodem, &set);
if (select(fdmodem+1, NULL, &set, NULL, &timeout) > 0)
{
if (FD_ISSET(fdmodem, &set)) return TRUE;
}
return FALSE;
}

/* Get a char from the modem */
char com_getchar()
{
char ch;

read(fdmodem, &ch, 1);
return(ch);
}

/* Send a char to the modem */
void com_sendchar(char ch)
{
write(fdmodem, &ch, 1);
}

int com_write(char *buff, int nmax)
{
int n;
n = strlen(buff);
if (nmax>0&&n>nmax) n = nmax;
return write(fdmodem,buff,n);
}

int com_read(char *buff, int nmax)
{
return read(fdmodem,buff,nmax);
}