标签：
目录
1、串口配置函数
2、打开串口
3、读写串口
总结：这些程序都是从书上抄来的，都是最最简单的程序，写在这里只是想写个大概的思路，具体的函数说明可以看书，其中值得说的就是两个函数，一个是
fcntl（fd，F_SETFL,0）//恢复串口为阻塞模式
还有一个是select（fd+1，&rd，NULL,NULL,NULL）//利用select函数来实现多个串口的读写
1、串口配置函数
/************************************************************** 功能描述：使串口设置参数生效 **************************************************************/ int set_opt(int fd,int nSpeed, int nBits, char nEvent, int nStop) { struct termios newtio,oldtio; printf("Initial......\n"); if ( tcgetattr( fd,&oldtio) != 0) { perror("SetupSerial 1"); return -1; } bzero( &newtio, sizeof( newtio ) ); newtio.c_cflag |= CLOCAL | CREAD; newtio.c_cflag &= ~CSIZE; switch( nBits ) { 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_iflag |= (INPCK | ISTRIP); newtio.c_cflag |= PARENB; newtio.c_cflag &= ~PARODD; break; case ‘N‘: newtio.c_cflag &= ~PARENB; break; } switch( nSpeed ) { case 2400: cfsetispeed(&newtio, B2400); cfsetospeed(&newtio, B2400); break; case 4800: cfsetispeed(&newtio, B4800); cfsetospeed(&newtio, B4800); break; case 9600: cfsetispeed(&newtio, B9600); cfsetospeed(&newtio, B9600); break; case 115200: cfsetispeed(&newtio, B115200); cfsetospeed(&newtio, B115200); break; case 460800: cfsetispeed(&newtio, B460800); cfsetospeed(&newtio, B460800); break; default: cfsetispeed(&newtio, B9600); cfsetospeed(&newtio, B9600); break; } if( nStop == 1 ) newtio.c_cflag &= ~CSTOPB; else if ( nStop == 2 ) newtio.c_cflag |= CSTOPB; newtio.c_cc[VTIME] = 0; newtio.c_cc[VMIN] = 0; tcflush(fd,TCIFLUSH); if((tcsetattr(fd,TCSANOW,&newtio))!=0) { perror("com set error"); return -1; } printf("set done!\n"); return 0; }
2、打开串口
int open_port(int comport) { int fd; char *dev[]={"/dev/ttyS0","/dev/ttyS1","/dev/ttyS2","/dev/ttyUSB0"}; long vdisable; if (comport==1) { fd = open( "/dev/ttyS0", O_RDWR|O_NOCTTY|O_NDELAY); if (-1 == fd){ perror("Can‘t Open Serial Port"); return(-1); } } else if(comport==2) { fd = open( "/dev/ttyS1", O_RDWR|O_NOCTTY|O_NDELAY); if (-1 == fd){ perror("Can‘t Open Serial Port"); return(-1); } } else if (comport==3) { fd = open( "/dev/ttyS2", O_RDWR|O_NOCTTY|O_NDELAY); if (-1 == fd){ perror("Can‘t Open Serial Port"); return(-1); } } else { fd = open( "/dev/ttyUSB0", O_RDWR|O_NOCTTY|O_NDELAY); if (-1 == fd){ perror("Can‘t Open Serial Port"); return(-1); } } if(fcntl(fd, F_SETFL, 0)<0) printf("fcntl failed!\n"); else //printf("fcntl=%d\n",fcntl(fd, F_SETFL,0)); fcntl(fd, F_SETFL,0); if(isatty(STDIN_FILENO)==0) printf("standard input is not a terminal device\n"); else //printf("isatty success!\n"); ; //printf("fd-open=%d\n",fd); return fd; }
3、读写串口
int main(void) { int fd; int nread,i; char buff[]="hello\n"; if(fd=open_port(fd,1)<0) { perror("open_port error"); return; } if(i=set_opt(fd,115200,8,‘N‘,1)<0) { perror("set_opt error"); return; } printf("fd=%d\n",fd); nread=read(fd,buff,8);//读串口 printf("nread=%d,%s\n",nread,buff); close(fd); return; }
int main(void) { int fd; int nread,i; char buff[]="hello\n"; fd_set rd; if(fd=open_port(fd,1)<0) { perror("open_port error"); return; } if(i=set_opt(fd,115200,8,‘N‘,1)<0) { perror("set_opt error"); return; } //利用select函数实现多个串口的读写 FD_ZERO(&rd); FD_SET(fd,&rd); while(FD_ISSET(fd,&rd)) { if(select(fd+1,&rd,NULL,NULL,NULL)<0) { perror("select"); } else { while((nread=read(fd,buff,8))>0) { printf("nread=%d,%s",nrade,buff); } } } close(fd); return; }
标签：
原文地址：http://www.cnblogs.com/void0/p/4259095.html
