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2台机器通过串口线连接(PC上标识是COM1,COM2口),目的是进行通讯.使用raw mode方式只能写不能读.
/* 写端 */
int
main(int argc, char **argv)
{
int fd;
int nwrite,nread;
int len;
char buff[128] = "send infomation\n"; /* send buffer */
struct termios options;
if(argc != 2){
printf("Usage: %s serialport\n",argv[0]);
exit(1);
}
len = strlen(buff);
fd = OpenDev(argv[1]); /* open the device */
if(fd == -1){
exit(1);
}
Set_speed(fd,19200); /* set serial baud */
if ( tcgetattr( fd,&options) != 0) {
perror("SetupSerial get");
return(FALSE);
}
/* 设置软件流缓冲 */
options.c_iflag |= (IXON | IXOFF | IXANY);
options.c_cflag &= ~CSIZE;
/* raw mode */
options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); /*Input*/
options.c_oflag &= ~OPOST; /*Output*/
if (tcsetattr(fd,TCSANOW,&options) != 0){
perror("SetupSerial set");
return (FALSE);
}
if (Set_Parity(fd,8,1,'N') == FALSE){
printf("Set Parity Error\n");
exit (1);
}
while (1){
int tol = 0;
puts("Ready to write!");
if((nwrite = write(fd, buff, len)) < 0){
perror("write");
exit(1);
}
printf("nwrite == %d\n",nwrite);
printf("buff == %s\n\n",buff);
sleep(3);
}
close(fd);
return 0;
}
int
OpenDev(char *Dev)
{
int fd = open( Dev, O_RDWR );
//int fd = open(Dev, O_RDWR | O_NOCTTY | O_NDELAY);
if (fd == -1){
perror("Can't Open Serial Port");
return -1;
}
else
return fd;
}
/**
*@brief 设置串口通信速率
*@param fd 类型 int 打开串口的文件句柄
*@param speed 类型 int 串口速度
*@return void
*/
void
Set_speed(int fd, int speed)
{
int i;
int status;
struct termios Opt;
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, };
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 fd");
return;
}
tcflush(fd,TCIOFLUSH);
}
}
}
/**
*@brief 设置串口数据位,停止位和效验位
*@param fd 类型 int 打开的串口文件句柄
*@param databits 类型 int 数据位 取值 为 7 或者8
*@param stopbits 类型 int 停止位 取值为 1 或者2
*@param parity 类型 int 效验类型 取值为N,E,O,,S
*/
int
Set_Parity(int fd,int databits,int stopbits,int parity)
{
struct termios options;
if ( tcgetattr( fd,&options) != 0) {
perror("SetupSerial get");
return(FALSE);
}
/* set databit */
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);
}
/* set paritybit */
switch (parity){
case 'n':
case 'N': /* not parity */
options.c_cflag &= ~PARENB; /* Clear parity enable */
options.c_iflag &= ~INPCK; /* Enable parity checking */
break;
case 'o':
case 'O':
options.c_cflag |= (PARODD | PARENB); /* 设置为奇效验*/
options.c_iflag |= INPCK; /* Disnable parity checking */
break;
case 'e':
case 'E':
options.c_cflag |= PARENB; /* Enable parity */
options.c_cflag &= ~PARODD; /* 转换为偶效验*/
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);
}
/* set stop bit */
switch (stopbits){
case 1:
options.c_cflag &= ~CSTOPB; /* one stopbit */
break;
case 2:
options.c_cflag |= CSTOPB; /* two stopbit */
break;
default:
fprintf(stderr,"Unsupported stop bits\n");
return (FALSE);
}
/* Set input parity option */
if (parity != 'n')
options.c_iflag |= INPCK;
tcflush(fd,TCIFLUSH);
/* set timeout 15 seconds for read */
//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 set");
return (FALSE);
}
return (TRUE);
} |
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