转载:http://blog.sina.com.cn/s/blog_6cb543ef0100x90j.html
今日编写了一个串口通讯程序,但是本机只有一个串口,无法验证程序的正确性,于是想到在linux下面增加一对虚拟串口
Python:
#! /usr/bin/env python #coding=utf-8 import pty import os import select def mkpty(): # 打开伪终端 master1, slave = pty.openpty() slaveName1 = os.ttyname(slave) master2, slave = pty.openpty() slaveName2 = os.ttyname(slave) print ‘\nslave device names: ‘, slaveName1, slaveName2 return master1, master2 if __name__ == "__main__": master1, master2 = mkpty() while True: rl, wl, el = select.select([master1,master2], [], [], 1) for master in rl: data = os.read(master, 128) print "read %d data." % len(data) if master==master1: os.write(master2, data) else: os.write(master1, data)
程序名叫mkptych.py,在终端里运行“python mkptych.py &”,这样就可以生成一个基于pty(伪终端)的虚拟端口对,两个设备名会显示在终端里。然后就可以利用这两个设备名在本机上进行虚拟串口之类的调试,使用完后用ps查看这个python进程的pid号,然后kill掉即可。
下面编写一个用上述虚拟串口的使用程序:
receiver.c
#include <stdio.h> #include <string.h> #include <malloc.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <unistd.h> #include <termios.h> #include <math.h> #define MAX_BUFFER_SIZE 512 int fd, s; int open_serial() { //这里的/dev/pts/27是使用mkptych.py虚拟的两个串口名字之一 fd = open("/dev/pts/27", O_RDWR|O_NOCTTY|O_NDELAY); if(fd == -1) { perror("open serial port error!\n"); return -1; } printf("open /dev/ttyS0.\n"); return 0; } int main() { char hd[MAX_BUFFER_SIZE], *rbuf; int flag_close, retv; struct termios opt; retv = open_serial(); if(retv < 0) { printf("Open serrial port error!\n"); return -1; } tcgetattr(fd, &opt); cfmakeraw(&opt); cfsetispeed(&opt, B9600); cfsetospeed(&opt, B9600); tcsetattr(fd, TCSANOW, &opt); rbuf = hd; printf("Ready for receiving data...\n"); while(1) { while((retv = read(fd, rbuf, 1)) > 0) printf( "%c ", *rbuf); } printf("\n"); flag_close = close(fd); if(flag_close == -1) printf("Close the device failure!\n"); return 0; }
send.c
#include <stdio.h> #include <string.h> #include <malloc.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <unistd.h> #include <termios.h> #define MAX_BUFFER_SIZE 512 int fd, flag_close; int open_serial() { //这里的/dev/pts/28是使用mkptych.py虚拟的两个串口名字之一 fd = open("/dev/pts/28", O_RDWR | O_NOCTTY | O_NONBLOCK); if(fd == -1) { perror("open serial port error!\n"); return -1; } printf("Open serial port success!"); return 0; } int main(int argc, char* argv[]) { char sbuf[] = {"Hello, this is a serial port test!\n"}; int retv; struct termios option; retv = open_serial(); if(retv < 0) { perror("open serial port error!\n"); return -1; } printf("Ready for sending data...\n"); tcgetattr(fd, &option); cfmakeraw(&option); cfsetispeed(&option, B9600); cfsetospeed(&option, B9600); tcsetattr(fd, TCSANOW, &option); int length = sizeof(sbuf); retv = write(fd, sbuf, length); if(retv == -1) { perror("Write data error!\n"); return -1; } printf("The number of char sent is %d\n", retv); return 0; }
编译运行即可,呵呵.
时间: 2024-10-08 04:37:16