在嵌入式开发中一些设备如WiFi、蓝牙......都会通过串口进行主机与从机间通信,串口一般以每次1bit位进行传输,效率相对慢。
在linux系统下串口的编程有如下几个步骤,最主要的是串口初始化!
1.打开串口 open(“/dev/XXXX”, O_NOCTTY|O_RDWR)
2.初始化串口 见下面实例。
3.对串口读写操作
4.关闭串口
#include <termios.h>
/**
*fd: 串口描述符
*nbits: 数据位
*nvent: 奇偶校验位
*nspeed: 波特率
*nstop: 停止位
**/
bool set_opt(int fd, int nbits, char nevent, int nspeed, int nstop)
{
struct termios newtio, oldtio;
if (!isatty(fd)) {
perror("is not a termios device");
return false;
}
if (tcgetattr(fd, &oldtio) != 0) {
perror("tcgetattr error");
return false;
}
newtio.c_cflag |= CLOCAL | CREAD;
newtio.c_cflag &= ~CSIZE;
switch(nbits) {
case 5:
newtio.c_cflag |= CS5;
break;
case 6:
newtio.c_cflag |= CS6;
break;
case 7:
newtio.c_cflag |= CS7;
break;
case 8:
newtio.c_cflag |= CS8;
break;
}
switch(nevent) {
case 'O':
newtio.c_cflag |= PARENB;
newtio.c_cflag |= PARODD;
newtio.c_iflag |= (INPCK | ISTRIP);
break;
case 'E':
newtio.c_cflag |= PARENB;
newtio.c_cflag &= ~PARODD;
newtio.c_iflag |= (INPCK | ISTRIP);
break;
case 'N':
newtio.c_cflag &= ~PARENB;
break;
}
switch(nspeed) {
case 115200:
cfsetospeed(&newtio, B115200);
cfsetispeed(&newtio, B115200);
break;
case 9600:
cfsetospeed(&newtio, B9600);
cfsetispeed(&newtio, B9600);
break;
case 2400:
cfsetospeed(&newtio, B2400);
cfsetispeed(&newtio, B2400);
break;
case 4800:
cfsetospeed(&newtio, B4800);
cfsetispeed(&newtio, B4800);
break;
case 460800:
cfsetospeed(&newtio, B460800);
cfsetispeed(&newtio, B460800);
break;
default:
cfsetispeed(&newtio, B9600);
cfsetospeed(&newtio, B9600);
break;
}
if (1 == nstop) {
newtio.c_cflag &= ~CSTOPB;
} else if (2 == nstop) {
newtio.c_cflag |= CSTOPB;
}
newtio.c_cc[VTIME] = 0;
newtio.c_cc[VMIN] = 0;
tcflush(fd, TCIFLUSH);
if (tcsetattr(fd, TCSANOW, &newtio) != 0) {
perror("comX set error");
return false;
}
return true;
}