本文共 4586 字，大约阅读时间需要 15 分钟。
普通单片机的串口操作比较容易，但是基于Linux系统的串口操作难不难呢？其实，基于Linux操作系统的串口操作分为两个部分：串口驱动部分（底层驱动与设备注册）与串口的应用程序（用户程序）。一般厂家或是Linux内核已经提供了基于开发板的串口驱动，只需要修改或是注册相应的串口设备，就可以直接使用了。因此，只需要写用户应用程序即可。
我手头上有一块AT91SAM9261EK的开发板，为了学习Linux买的，现在用到了，因此，学习一下串口的操作。
程序如下：
//rs232_test.c#includeMakefile文件如下：#include #include #include #include #include #include #include #include #define BAUDRATE B9600static int open_com(char *dev_name, long com_baud, int com_data, int com_pry, int com_stop){ uint baud = 0, data = 0, parity = 0, stop = 0; struct termios strNewTio; int fd; //set baudrate: switch(com_baud) { case 50: baud = B50; break; case 75: baud = B75; break; case 110: baud = B110; break; case 134: baud = B134; break; case 150: baud = B150; break; case 200: baud = B200; break; case 300: baud = B300; break; case 600: baud = B600; break; case 1200: baud = B1200; break; case 1800: baud = B1800; break; case 4800: baud = B4800; break; case 9600: baud = B9600; break; case 19200: baud = B19200; break; case 38400: baud = B38400; break; case 57600: baud = B57600; break; case 115200: baud = B115200; break; case 230400: baud = B230400; break; default: baud = B9600; } //set databits: switch(com_data) { case 5: data = CS5; break; case 6: data = CS6; break; case 7: data = CS7; break; case 8: data = CS8; break; default: data = CS8; } //set parity: switch(com_pry) { case 0: parity = 0; break; case 1: parity = PARENB | PARODD; break; case 2: parity = PARENB; break; default: parity = 0; } //set stopbits: switch(com_stop) { case 1: stop = 0; break; case 2: stop = CSTOPB; break; default: stop = 0; } fd = open(dev_name, O_RDWR | O_NOCTTY ); if (fd < 0) { perror("com open() error"); return -1; } //set parameters: tcgetattr(fd, &strNewTio); strNewTio.c_cflag = baud | data | parity | stop | CREAD | CLOCAL; strNewTio.c_iflag = 0; strNewTio.c_lflag = 0; strNewTio.c_oflag = 0; if (tcsetattr(fd, TCSANOW, &strNewTio) < 0) { close(fd); perror("com tcsetattr() error"); return -1; } return fd;}int main(int argc, char *argv[]){ struct timeval tp; long time1=0; long time2=0; int fd1,fd2; struct termios tio1,tio2; int res,cnt,i; int mode = 1; //rs232 mode unsigned char c; unsigned char dev1[10]; unsigned char dev2[10]; int tmp1,tmp2; if (argc == 0x0) { printf("Usage : rs232 com_no\n"); return 0; } else { tmp1 = atoi(argv[1]); if (tmp1 > 16 ) { printf("Usage : rs232_loopback com_no com_no\n"); return 0; } else { sprintf(dev1, "/dev/ttyS%d", tmp1); } } fd1 = open_com(dev1, 9600, 8, 0, 1); if (fd1 < 0) { printf("can not open %s\n", dev1); close(fd1); return 0; } else { printf("Open COM %s Success!!\n", dev1); } // clear the noise, made by change UART modeusleep(10000); char wr = 'k'; char rd [1000]; int ret; rd[0] = 0; while(1) { printf("=======%d\n ", i++); //write(fd1, &wr, 1); printf("=send:%c ", wr); usleep(100); ret = read(fd1, rd, 512); if (ret) { printf("\n=========receive:%s\n", rd); write(fd1, rd, strlen(rd)); memset(rd, 0, 512); } } return 0;}
然后连接好此串口的串口线，通过ftp等放到开发板的根文件系统里，在执行目录下执行：
# ./rs232_test 1 //这里打开/dev/ttyS1
打开成功，就会提示成功的信息，就可以通过串口助手往相应的串口上发送数据了。
转载地址：http://fzfpz.baihongyu.com/