我是c/c++新手,我正在尝试使用十六进制值通过uart进行通信。
设备端口:/dev/ttys2。波特率:38400
我正在使用redis订阅消息。为了测试,我使用了“白蚁”,一个rs232终端来模拟。
我找到了一些非常好用的指南,问题是当我试图阅读信息时,有些字节/字符会弄乱它。
以下是我的连接代码:
this->fd = open(device,O_RDWR | O_NOCTTY);
/*---------- Setting the Attributes of the serial port using termios structure --------- */
tcgetattr(this->fd, &SerialPortSettings); /* Get the current attributes of the Serial port */
/* Setting the Baud rate */
cfsetispeed(&SerialPortSettings,B38400); /* Set Read Speed as 38400 */
cfsetospeed(&SerialPortSettings,B38400); /* Set Write Speed as 38400 */
/* 8N1 Mode */
SerialPortSettings.c_cflag &= ~PARENB; /* Disables the Parity Enable bit(PARENB),So No Parity */
SerialPortSettings.c_cflag &= ~CSTOPB; /* CSTOPB = 2 Stop bits,here it is cleared so 1 Stop bit */
SerialPortSettings.c_cflag &= ~CSIZE; /* Clears the mask for setting the data size */
SerialPortSettings.c_cflag |= CS8; /* Set the data bits = 8 */
SerialPortSettings.c_cflag &= ~CRTSCTS; /* No Hardware flow Control */
SerialPortSettings.c_cflag |= CREAD | CLOCAL; /* Enable receiver,Ignore Modem Control lines */
SerialPortSettings.c_iflag &= ~(IXON | IXOFF | IXANY); /* Disable XON/XOFF flow control both i/p and o/p */
SerialPortSettings.c_iflag &= ~(ICANON | ECHO | ECHOE | ISIG); /* Non Cannonical mode */
SerialPortSettings.c_oflag &= ~OPOST; /*No Output Processing*/
SerialPortSettings.c_oflag = 0;
/* Setting Time outs */
SerialPortSettings.c_cc[VMIN] = 1; /* Read at least X characters */
SerialPortSettings.c_cc[VTIME] = 0; /* Wait indefinetly */
tcflush(this->fd, TCIFLUSH);
if((tcsetattr(this->fd,TCSANOW,&SerialPortSettings)) != 0) { /* Set the attributes to the termios structure*/
printf("\n ERROR ! in Setting attributes");
}
else {
tcsetattr(fd, TCSANOW, &SerialPortSettings);
printf("\n BaudRate = 38400 \n StopBits = 1 \n Parity = none\n\n");
}
下面是阅读代码:
char read_buffer[32];
int bytes_read;
while(true) {
bytes_read = read(serialport.fd, &read_buffer, sizeof(read_buffer)); /* Read the data */
printf("bytes read: %d", bytes_read);
if (bytes_read < 0) {
printf("Error reading: %s", strerror(errno));
}
else if (bytes_read > 0) {
//read_buffer[bytes_read] = '\0';
printf("\n");
printf("HEX:");
for (int i=0; i<bytes_read; i++) { /*printing only the received characters*/
printf(" %02x",read_buffer[i]);
}
printf("\n");
printf("+----------------------------------+\n");
/*#if defined(MODULE_REDIS) || defined(MODULE_ALL)
//redis.publish("channel:uart:ack", read_buffer);
redis.publish("channel:uart:ack", vectorUint8toHex(read_data).c_str());
#endif*/
}
std::this_thread::sleep_for(std::chrono::milliseconds(1));
}
当我发送消息0x24010102003040506070809af23时,它只显示8个字节(字节0x03和0x04与消息相混淆)
OUTPUT:
bytes read: 0bytes read: 8
HEX: 05 06 07 08 09 af 23 0a
+----------------------------------+
但当我发送0x2401010200000506070809af23时,它工作正常
OUTPUT:
bytes read: 14
HEX: 24 01 01 02 00 00 05 06 07 08 09 af 23 0a
+----------------------------------+
我做错了什么?还有一件事。使用termite必须打开“append lf”设置,否则我无法读取消息,但这会将“0a”添加到我的消息中,这与串行端口的配置有关吗?
1条答案
按热度按时间lqfhib0f1#
好的,问题是二进制中的一些字节是0x03和0x04,它们是ascii的“文本结束”和“传输结束”。在配置上缺少这一行:
感谢这些评论,我搜索了一些缺少的配置并找到了它。
还有一篇关于我的问题的帖子,我当时没有找到:二进制串口读取c中丢失的字节