openwrt (linux)串口通信
linux-dash
A beautiful web dashboard for Linux
项目地址:https://gitcode.com/gh_mirrors/li/linux-dash
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1. 基本的串口通信程序。先读取内容,再将内容写回串口。
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>
#include <errno.h>
main()
{
int fd;
int i;
int len;
int n = 0;
char read_buf[256];
char write_buf[256];
struct termios opt;
fd = open("/dev/ttyATH0", O_RDWR|O_NOCTTY|O_NDELAY);
if(fd == -1)
{
perror("open serial 0\n");
exit(0);
}
tcgetattr(fd, &opt);
bzero(&opt, sizeof(opt));
tcflush(fd, TCIOFLUSH);
cfsetispeed(&opt, B115200);
cfsetospeed(&opt, B115200);
opt.c_cflag &= ~CSIZE;
opt.c_cflag |= CS8;
opt.c_cflag &= ~CSTOPB;
opt.c_cflag &= ~PARENB;
opt.c_cflag &= ~CRTSCTS;
opt.c_cflag |= (CLOCAL | CREAD);
opt.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
opt.c_oflag &= ~OPOST;
opt.c_cc[VTIME] = 0;
opt.c_cc[VMIN] = 0;
tcflush(fd, TCIOFLUSH);
printf("configure complete\n");
if(tcsetattr(fd, TCSANOW, &opt) != 0)
{
perror("serial error");
return -1;
}
printf("start send and receive data\n");
while(1)
{
n = 0;
len = 0;
bzero(read_buf, sizeof(read_buf));
bzero(write_buf, sizeof(write_buf));
while( (n = read(fd, read_buf, sizeof(read_buf))) > 0 )
{
for(i = len; i < (len + n); i++)
{
write_buf[i] = read_buf[i - len];
}
len += n;
}
write_buf[len] = '\0';
printf("Len %d \n", len);
printf("%s \n", write_buf);
n = write(fd, write_buf, len);
printf("write %d chars\n",n);
sleep(2);
}
}
2. 注意
opt.c_cc[VTIME] = 0;
opt.c_cc[VMIN] = 0;
在这两个值均为0 的情况下,read不管有没有数据都会立即返回。详细情况在linux下man tcsetattr.
如果不设定这两个值,那么read只有收到回车后才会读取缓存中的数据。
程序大部分转载自:http://www.cnblogs.com/lovemo1314/archive/2010/10/29/1864327.html
该链接的程序部分有误。
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