include

define BUFFER_SIZE 1024

define HOST_PORT 0

int set_port(int fd, int baud_rate, int data_bits, char parity, int stop_bits) { struct termios newtio,oldtio; if( tcgetattr(fd,&oldtio) != 0) { perror("Setup Serial 1"); return -1; } bzero(&newtio,sizeof(newtio)); newtio.c_cflag |= CLOCAL | CREAD; newtio.c_cflag &= ~CSIZE; / set baud_speed/ switch(baud_rate) { 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 19200: cfsetispeed(&newtio,B19200); cfsetospeed(&newtio,B19200); break; case 38400: cfsetispeed(&newtio,B38400); cfsetospeed(&newtio,B38400); break; default: case 115200: cfsetispeed(&newtio,B115200); cfsetospeed(&newtio,B115200); break; } / set data_bits upon 7 or 8/ switch(data_bits) { case 7: newtio.c_cflag |= CS7; break; default : case 8: newtio.c_cflag |= CS8; break; } // switch(parity) { default: case 'N': case 'n': { newtio.c_cflag &= ~PARENB; newtio.c_iflag &= ~INPCK; } break; case 'o': case 'O': { newtio.c_cflag |= (PARODD | PARENB); newtio.c_iflag |= INPCK; } break; case 'e': case 'E': { newtio.c_cflag |= PARENB; newtio.c_cflag &= ~PARODD; newtio.c_iflag |= INPCK; } break; case 's': case 'S': { newtio.c_cflag &= ~PARENB; newtio.c_cflag &= ~CSTOPB; } break; } /set stop_bits 1 or 2 / switch(stop_bits) { default: case 1: { newtio.c_cflag &= ~CSTOPB; } break; case 2: { newtio.c_cflag |= CSTOPB; } break; } newtio.c_cc = 0; newtio.c_cc = 1; tcflush(fd,TCIFLUSH); if((tcsetattr(fd,TCSANOW,&newtio)) != 0) { perror("com set error"); return -1; } printf("set UART done!n"); return 0; } int open_port(int com_port) { int fd = 0; char *dev[] = { "/dev/ttyS0", "/dev/ttyS1", "/dev/ttyS2","/dev/ttyS3", "/dev/ttyS4", "/dev/ttyS5", "/dev/ttyS6" }; if((com_port 6) ) { printf("the port is out range"); return -1; } fd = open(dev, O_RDWR | O_NOCTTY | O_NDELAY); if(fd < 0) { perror("open serial port"); return -1; } if(fcntl(fd, F_SETFL,0) < 0) { perror("fcntl F_SETFL"); return -1; } if(isatty(fd) == 0) { perror("isatty is not a terminal device"); return -1; } return fd; }

int main(void) { int fd = 0; char buffer2[]="rn"; char buffer = {0}; if((fd = open_port(HOST_PORT)) == -1){ perror("open port"); return -1; } if(set_port(fd,115200,8,'N',1)== -1) { perror("set port"); return -1; } do { printf("Input some words:n"); memset(buffer,0,BUFFER_SIZE); if(fgets(buffer,BUFFER_SIZE,stdin) == NULL) { perror("fgets"); break; } write(fd,buffer,strlen(buffer)); write(fd,buffer2,strlen(buffer2));} while(strncmp(buffer,"quit",4)); close(fd); return 0; }