linux 串口自环测试程序。两种不同的方法。select ,以及多线程方法。
select uart_sendrecv_notv.rar
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h> //文件控制定义
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#include <termios.h>//终端控制定义
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#include <errno.h>
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#include <unistd.h>
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#include <string.h>
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#define DEVICE "/dev/ttyUSB0"
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#define S_TIMEOUT 1
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int serial_fd = 0;
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//打开串口并初始化设置
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init_serial(void)
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{
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serial_fd = open(DEVICE, O_RDWR | O_NOCTTY | O_NDELAY);
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if (serial_fd < 0) {
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perror("open");
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return -1;
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}
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//串口主要设置结构体termios <termios.h>
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struct termios options;
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/**1. tcgetattr函数用于获取与终端相关的参数。
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*参数fd为终端的文件描述符,返回的结果保存在termios结构体中
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*/
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tcgetattr(serial_fd, &options);
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/**2. 修改所获得的参数*/
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options.c_cflag |= (CLOCAL | CREAD);//设置控制模式状态,本地连接,接收使能
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options.c_cflag &= ~CSIZE;//字符长度,设置数据位之前一定要屏掉这个位
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options.c_cflag &= ~CRTSCTS;//无硬件流控
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options.c_cflag |= CS8;//8位数据长度
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options.c_cflag &= ~CSTOPB;//1位停止位
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options.c_iflag |= IGNPAR;//无奇偶检验位
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options.c_oflag = 0; //输出模式
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options.c_lflag = 0; //不激活终端模式
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cfsetospeed(&options, B115200);//设置波特率
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/**3. 设置新属性,TCSANOW:所有改变立即生效*/
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tcflush(serial_fd, TCIFLUSH);//溢出数据可以接收,但不读
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tcsetattr(serial_fd, TCSANOW, &options);
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return 0;
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}
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/**
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*串口发送数据
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*@fd:串口描述符
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*@data:待发送数据
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*@datalen:数据长度
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*/
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unsigned int total_send = 0 ;
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int uart_send(int fd, char *data, int datalen)
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{
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int len = 0;
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len = write(fd, data, datalen);//实际写入的长度
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if(len == datalen) {
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total_send += len ;
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printf("total_send is %d\n",total_send);
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return len;
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} else {
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tcflush(fd, TCOFLUSH);//TCOFLUSH刷新写入的数据但不传送
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return -1;
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}
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return 0;
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}
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/**
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*串口接收数据
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*要求启动后,在pc端发送ascii文件
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*/
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unsigned int total_length = 0 ;
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int uart_recv(int fd, char *data, int datalen)
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{
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int len=0, ret = 0;
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fd_set fs_read;
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struct timeval tv_timeout;
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FD_ZERO(&fs_read);
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FD_SET(fd, &fs_read);
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#ifdef S_TIMEOUT
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tv_timeout.tv_sec = (10*20/115200+2);
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tv_timeout.tv_usec = 0;
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ret = select(fd+1, &fs_read, NULL, NULL, NULL);
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#elif
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ret = select(fd+1, &fs_read, NULL, NULL, tv_timeout);
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#endif
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// printf("ret = %d\n", ret);
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//如果返回0,代表在描述符状态改变前已超过timeout时间,错误返回-1
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if (FD_ISSET(fd, &fs_read)) {
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len = read(fd, data, datalen);
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total_length += len ;
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printf("total len = %d\n", total_length);
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return len;
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} else {
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perror("select");
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return -1;
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}
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return 0;
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}
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int main(int argc, char **argv)
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{
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init_serial();
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char buf[]="hello world";
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char buf1[11] ;
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memset(buf1,0,sizeof(char)*11);
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while(1)
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{
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uart_send(serial_fd, buf, 11);
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printf("\n");
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sleep(1);
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//if(uart_recv(serial_fd, buf1, 11) > 0)
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uart_recv(serial_fd, buf1, 11);
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printf("receive: %s\n", buf1);
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memset(buf1,0,sizeof(char)*11);
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}
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close(serial_fd);
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return 0;
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}
多线程方法sertest.rar
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/****************************************************************************
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*
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* Copyright (c) 2006 Dave Hylands <dhylands@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Alternatively, this software may be distributed under the terms of BSD
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* license.
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*
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* See README and COPYING for more details.
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*
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****************************************************************************/
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/**
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*
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* sertest.c
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*
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* PURPOSE:
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*
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* This implements a sample program for accessing the serial port.
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*
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*****************************************************************************/
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/* ---- Include Files ---------------------------------------------------- */
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <sys/ioctl.h>
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#include <sys/unistd.h>
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#include <pthread.h>
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#include <signal.h>
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#include <getopt.h>
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#include <termios.h>
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/* ---- Public Variables ------------------------------------------------- */
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int gFd = -1;
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int gVal;
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/* ---- Private Constants and Types -------------------------------------- */
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/* ---- Private Variables ------------------------------------------------ */
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struct option gLongOption[] =
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{
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// option A Flag V (has_arg, flag, val)
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// ----------- - ---- ---
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{ "baud", 1, NULL, 'b' },
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{ "debug", 0, NULL, 'd' },
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{ "help", 0, NULL, 'h' },
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{ "port", 1, NULL, 'p' },
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{ "verbose", 0, NULL, 'v' },
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{ 0 },
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};
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struct
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{
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speed_t speed;
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unsigned baudRate;
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} gBaudTable[] =
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{
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{ B50, 50 },
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{ B75, 75 },
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{ B110, 110 },
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{ B134, 134 },
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{ B150, 150 },
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{ B200, 200 },
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{ B300, 300 },
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{ B600, 600 },
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{ B1200, 1200 },
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{ B1800, 1800 },
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{ B2400, 2400 },
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{ B4800, 4800 },
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{ B9600, 9600 },
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{ B19200, 19200 },
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{ B38400, 38400 },
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{ B57600, 57600 },
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{ B115200, 115200 },
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{ B230400, 230400 }
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};
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#define ARRAY_LEN(x) ( sizeof( x ) / sizeof( x[ 0 ]))
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int gVerbose = 0;
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int gDebug = 0;
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int gPortFd = -1;
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/* ---- Private Function Prototypes -------------------------------------- */
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void *ReadSerialThread( void *param );
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void *ReadStdinThread( void *param );
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char *StrMaxCpy( char *dst, const char *src, size_t maxLen );
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char *StrMaxCat( char *dst, const char *src, size_t maxLen );
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void Usage( void );
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/* ---- Functions -------------------------------------------------------- */
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#if defined(__CYGWIN__)
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// Cygwin seems to be missing cfmakeraw, so we provide a copy here.
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static void cfmakeraw(struct termios *termios_p)
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{
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termios_p->c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL|IXON);
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termios_p->c_oflag &= ~OPOST;
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termios_p->c_lflag &= ~(ECHO|ECHONL|ICANON|ISIG|IEXTEN);
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termios_p->c_cflag &= ~(CSIZE|PARENB);
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termios_p->c_cflag |= CS8;
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}
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#endif /* defined(__CYGWIN__) */
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/***************************************************************************
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*
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* main
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*
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****************************************************************************/
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int main( int argc, char **argv )
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{
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int sig;
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int rc;
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int opt;
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char devName[ 40 ];
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const char *baudStr = NULL;
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const char *portStr = "ttyS2";
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speed_t baudRate;
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sigset_t termSig;
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pthread_t readSerialThreadId;
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pthread_t readStdinThreadId;
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struct termios stdin_tio;
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struct termios stdin_tio_org;
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struct termios attr;
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// Parse the command line options
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while (( opt = getopt_long( argc, argv, "b:dhp:v", gLongOption, NULL )) > 0 )
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{
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switch ( opt )
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{
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case 'b':
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{
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baudStr = optarg;
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break;
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}
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case 'd':
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{
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gDebug = 1;
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break;
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}
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case 'p':
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{
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portStr = optarg;
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break;
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}
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case 'v':
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{
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gVerbose = 1;
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break;
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}
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case '?':
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case 'h':
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{
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Usage();
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return 1;
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}
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}
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}
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devName[ 0 ] = '\0';
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if ( portStr[ 0 ] != '/' )
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{
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StrMaxCpy( devName, "/dev/", sizeof( devName ));
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}
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StrMaxCat( devName, portStr, sizeof( devName ));
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baudRate = B0;
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if ( baudStr == NULL )
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{
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baudRate = B9600;
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}
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else
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{
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int baudIdx;
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int testBaud = atoi( baudStr );
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for ( baudIdx = 0; baudIdx < ARRAY_LEN( gBaudTable ); baudIdx++ )
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{
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if ( gBaudTable[ baudIdx ].baudRate == testBaud )
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{
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baudRate = gBaudTable[ baudIdx ].speed;
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break;
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}
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}
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if ( baudRate == B0 )
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{
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fprintf( stderr, "Unrecognized baud rate: '%s'\n", baudStr );
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exit( 1 );
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}
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}
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// Open the serial port initially using O_NONBLOCK so that we won't block waiting for
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// carrier detect.
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if (( gPortFd = open( devName, O_RDWR | O_EXCL | O_NONBLOCK )) < 0 )
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{
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fprintf( stderr, "Unable to open serial port '%s': %s\n", devName, strerror( errno ));
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exit( 2 );
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}
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// Now that the serial port is open, we can turn off the non-blocking behaviour (for us we want
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// the reads to have blocking semantics).
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fcntl( gPortFd, F_SETFL, fcntl( gPortFd, F_GETFL ) & ~O_NONBLOCK );
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if ( tcgetattr( gPortFd, &attr ) < 0 )
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{
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fprintf( stderr, "Call to tcgetattr failed: %s\n", strerror( errno ));
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exit( 3 );
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}
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cfmakeraw( &attr );
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// CLOCAL - Disable modem control lines
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// CREAD - Enable Receiver
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attr.c_cflag |= ( CLOCAL | CREAD );
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cfsetispeed( &attr, baudRate );
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cfsetospeed( &attr, baudRate );
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if ( tcsetattr( gPortFd, TCSAFLUSH, &attr ) < 0 )
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{
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fprintf( stderr, "Call to tcsetattr failed: %s\n", strerror( errno ));
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exit( 4 );
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}
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// Put stdin & stdout in unbuffered mode.
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setbuf( stdin, NULL );
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setbuf( stdout, NULL );
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sigemptyset( &termSig );
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sigaddset( &termSig, SIGINT );
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sigaddset( &termSig, SIGTERM );
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pthread_sigmask( SIG_BLOCK, &termSig, NULL );
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// Put stdin in raw mode (i.e. turn off canonical mode). Canonical mode
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// causes the driver to wait for the RETURN character so that line editing
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// can take place. We also want to turn off ECHO.
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if ( tcgetattr( fileno( stdin ), &stdin_tio_org ) < 0 )
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{
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fprintf( stderr, "Unable to retrieve terminal settings: %s\n", strerror( errno ));
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exit( 5 );
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}
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stdin_tio = stdin_tio_org;
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stdin_tio.c_lflag &= ~( ICANON | ECHO );
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stdin_tio.c_cc[VTIME] = 0;
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stdin_tio.c_cc[VMIN] = 1;
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if ( tcsetattr( fileno( stdin ), TCSANOW, &stdin_tio ) < 0 )
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{
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fprintf( stderr, "Unable to update terminal settings: %s\n", strerror( errno ));
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exit( 6 );
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}
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// Kick off the serial port reader thread.
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rc = pthread_create( &readSerialThreadId, NULL, ReadSerialThread, NULL );
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if ( rc != 0 )
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{
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fprintf( stderr, "Error creating ReadSerialThread: %s\n", strerror( rc ));
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exit( 7 );
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}
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// Kick off the stdin reader thread
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rc = pthread_create( &readStdinThreadId, NULL, ReadStdinThread, NULL );
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if ( rc != 0 )
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{
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fprintf( stderr, "Error creating ReadStdinThread: %s\n", strerror( rc ));
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exit( 7 );
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}
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// Wait for a termmination signal
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if (( rc = sigwait( &termSig, &sig )) != 0 )
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{
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fprintf( stderr, "sigwait failed\n" );
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}
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else
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{
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fprintf( stderr, "Exiting...\n" );
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}
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pthread_cancel( readSerialThreadId );
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pthread_cancel( readStdinThreadId );
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// Restore stdin back to the way it was when we started
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if ( tcsetattr( fileno( stdin ), TCSANOW, &stdin_tio_org ) < 0 )
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{
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fprintf( stderr, "Unable to update terminal settings: %s\n", strerror( errno ));
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exit( 6 );
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}
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// Unblock the termination signals so the user can kill us if we hang up
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// waiting for the reader threads to exit.
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pthread_sigmask( SIG_UNBLOCK, &termSig, NULL );
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pthread_join( readSerialThreadId, NULL );
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pthread_join( readStdinThreadId, NULL );
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close( gPortFd );
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if ( gVerbose )
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{
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fprintf( stderr, "Done\n" );
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}
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exit( 0 );
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return 0; // Get rid of warning about not returning anything
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}
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/***************************************************************************/
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/**
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* Thread which processes the incoming serial data.
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*/
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void *ReadSerialThread( void *param )
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{
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while ( 1 )
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{
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char ch;
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int bytesRead;
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if (( bytesRead = read( gPortFd, &ch, 10 )) < 0 )
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{
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fprintf( stderr, "Serial port read failed: %s\n", strerror( errno ));
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exit( 1 );
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}
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if ( gDebug )
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{
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if (( ch < ' ' ) || ( ch > '~' ))
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{
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fprintf( stderr, "Serial Read: 0x%02x '.'\n", ch );
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}
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else
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{
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fprintf( stderr, "Serial Read: 0x%02x '%c'\n", ch, ch );
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}
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}
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putc( ch, stdout );
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}
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return NULL;
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} // ReadSerialThread
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/***************************************************************************/
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/**
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* Thread which processes the incoming serial from stdin.
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*/
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void *ReadStdinThread( void *param )
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{
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while ( 1 )
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{
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char ch;
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int chInt = fgetc( stdin );
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if ( chInt < 0 )
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{
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fprintf( stderr, "Error reading stdin...\n" );
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break;
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}
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ch = (char)chInt;
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if ( gDebug )
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{
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if (( ch < ' ' ) || ( ch > '~' ))
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{
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fprintf( stderr, "stdin Read: 0x%02x '.'\n", ch );
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}
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else
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{
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fprintf( stderr, "stdin Read: 0x%02x '%c'\n", ch, ch );
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}
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}
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if ( write( gPortFd, &ch, 1 ) != 1 )
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{
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fprintf( stderr, "write to serial port failed: %s\n", strerror( errno ));
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break;
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}
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}
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return NULL;
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} // ReadStdinThread
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/***************************************************************************/
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/**
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* Concatenates source to the destination, but makes sure that the
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* destination string (including terminating null), doesn't exceed maxLen.
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*
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* @param dst (mod) String to concatnate onto.
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* @param src (in) String to being added to the end of @a dst.
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* @param maxLen (in) Maximum length that @a dst is allowed to be.
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*
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* @return A pointer to the destination string.
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*/
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char *StrMaxCat( char *dst, const char *src, size_t maxLen )
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{
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size_t dstLen = strlen( dst );
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if ( dstLen < maxLen )
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{
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StrMaxCpy( &dst[ dstLen ], src, maxLen - dstLen );
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}
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return dst;
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} /* StrMaxCat */
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/***************************************************************************/
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/**
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* Copies the source to the destination, but makes sure that the
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* destination string (including terminating null), doesn't exceed
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* maxLen.
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*
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* @param dst (out) Place to store the string copy.
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* @param src (in) String to copy.
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* @param maxLen (in) Maximum number of characters to copy into @a dst.
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*
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* @return A pointer to the destination string.
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*/
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char *StrMaxCpy( char *dst, const char *src, size_t maxLen )
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{
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if ( maxLen < 1 )
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{
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/*
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* There's no room in the buffer?
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*/
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return "";
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}
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if ( maxLen == 1 )
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{
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/*
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* There's only room for the terminating null character
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*/
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dst[ 0 ] = '\0';
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return dst;
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}
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/*
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* The Visual C++ version of strncpy writes to every single character
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* of the destination buffer, so we use a length one character smaller
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* and write in our own null (if required).
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*
-
* This allows the caller to store a sentinel in the last byte of the
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* buffer to detect overflows (if desired).
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*/
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strncpy( dst, src, maxLen - 1 );
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if (( strlen( src ) + 1 ) >= maxLen )
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{
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/*
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* The string exactly fits, or probably overflows the buffer.
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* Write in the terminating null character since strncpy doesn't in
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* this particular case.
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*
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* We don't do this arbitrarily so that the caller can use a sentinel
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* in the very end of the buffer to detect buffer overflows.
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*/
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dst[ maxLen - 1 ] = '\0';
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}
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return dst;
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} /* StrMaxCpy */
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/***************************************************************************
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*
-
* Usage
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*
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****************************************************************************/
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void Usage()
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{
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fprintf( stderr, "Usage: sertest [option(s)]\n" );
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fprintf( stderr, " Download a program via serial/i2c\n" );
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fprintf( stderr, "\n" );
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fprintf( stderr, " -b, --baud=baud Set the baudrate used\n" );
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fprintf( stderr, " -d, --debug Turn on debug output\n" );
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fprintf( stderr, " -h, --help Display this message\n" );
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fprintf( stderr, " -p, --port=port Set the I/O port\n" );
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fprintf( stderr, " -v, --verbose Turn on verbose messages\n" );
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-
} // Usage
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