Question

我正在测试Digitus USB - ＆gt; RS232转换器，使用Prolific PL2303芯片。目的是连接到GSP模块U-blox LEA 6H。我正在研究Ubuntu 12.10。要检查我是否可以正确运行转换器，我将其连接到Arduino Mega串行端口1。

我连接了两台设备：

Bus 005 Device 002: ID 0403:6001 Future Technology Devices International, Ltd FT232 USB-Serial (UART) IC
Bus 007 Device 003: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port

第一个是/ dev / ttyUSB0上的Arduino，/ dev / ttyUSB1上的转换器。当我使用/ dev / ttyUSB0下面的代码时，它工作得很好，我得到串口监视器数字0 ... 118。但是，当我将其更改为ttyUSB1时，结果会略有不同。我很抱歉代码中的混乱，它是从3个不同的教程编译。

PC的代码：

#include <stdio.h>    /* Standard input/output definitions */
#include <stdlib.h>
#include <stdint.h>   /* Standard types */
#include <string.h>   /* String function definitions */
#include <unistd.h>   /* UNIX standard function definitions */
#include <fcntl.h>    /* File control definitions */
#include <errno.h>    /* Error number definitions */
#include <termios.h>  /* POSIX terminal control definitions */
#include <sys/ioctl.h>
#include <getopt.h>
#include <iostream>

/* File descriptor for the port */
int fd;
int n;
uint8_t buffer[255];  /* Input buffer */
const char port_name[] = "/dev/ttyUSB0";

int serialport_init(const char* serialport, int baud)
{
    struct termios toptions;
    int fd;

    //fprintf(stderr,"init_serialport: opening port %s @ %d bps\n",
    //        serialport,baud);

    fd = open(serialport, O_RDWR | O_NOCTTY | O_NDELAY);
    if (fd == -1)  {
        perror("init_serialport: Unable to open port ");
        return -1;
    }

    if (tcgetattr(fd, &toptions) < 0) {
        perror("init_serialport: Couldn't get term attributes");
        return -1;
    }
    speed_t brate = baud; // let you override switch below if needed
    switch(baud) {
    case 4800:   brate=B4800;   break;
    case 9600:   brate=B9600;   break;
#ifdef B14400
    case 14400:  brate=B14400;  break;
#endif
    case 19200:  brate=B19200;  break;
#ifdef B28800
    case 28800:  brate=B28800;  break;
#endif
    case 38400:  brate=B38400;  break;
    case 57600:  brate=B57600;  break;
    case 115200: brate=B115200; break;
    }
    cfsetispeed(&toptions, brate);
    cfsetospeed(&toptions, brate);

    // 8N1
    toptions.c_cflag &= ~PARENB;
    toptions.c_cflag &= ~CSTOPB;
    toptions.c_cflag &= ~CSIZE;
    toptions.c_cflag |= CS8;
    // no flow control
    toptions.c_cflag &= ~CRTSCTS;

    toptions.c_cflag |= CREAD | CLOCAL;  // turn on READ & ignore ctrl lines
    toptions.c_iflag &= ~(IXON | IXOFF | IXANY); // turn off s/w flow ctrl

    toptions.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); // make raw
    toptions.c_oflag &= ~OPOST; // make raw

    // see: http://unixwiz.net/techtips/termios-vmin-vtime.html
    toptions.c_cc[VMIN]  = 0;
    toptions.c_cc[VTIME] = 20;

    if( tcsetattr(fd, TCSANOW, &toptions) < 0) {
        perror("init_serialport: Couldn't set term attributes");
        return -1;
    }

    return fd;
}

int main(void){
    fd = serialport_init(port_name, 19200);
    n=-1;
    for(uint8_t i=0; i<255; i++){
        buffer[i]=i;
    }
    n = write(fd, buffer, 120);
    if(n<0){
        fputs("write() failed!\n", stderr);
        printf("ERROR");
        return -1;
    }
    close(fd);
    std::cout << "Port closed";
    return 0;
}

Arduino奇怪的输出：

253 251 249 247 245 243 241 239 237 235 233 231 229 227 225 223 221 219 217 215 213 211 209 207 205 203 201 199 197 195 193 191 189 187 185 183 181 179 177 175 173 171 169 167 165 163 161 159 157 155 153 151 149 147 145 143 141 139 137 135 133 131 129 127 125 123 121 119 117 115 113 111 109 107 105 103 101 99 97 95 93 91 89 87 85 73 53 33

结果似乎是输入乘以2加1。

Prolific PL2303 Ubuntu vs Arduino Mega

0 个答案: