我在使用C#中的System.IO.Ports从串口读取数据时遇到了一些问题。唯一可行的方法是“读取”方法,但它只读取“已定义”的字符数,我需要读取所有可用数据,如“Tera Term”或“Hercules”。这是我读取缓冲区的DLL方法:
public String ReadMessage(String port, int timeout, int dataSize)
{
String res;
try
{
_serial_port = new SerialPort();
_serial_port.PortName = port;
_serial_port.BaudRate = 19200;
_serial_port.Parity = Parity.None;
_serial_port.DataBits = 8;
_serial_port.StopBits = StopBits.One;
_serial_port.Handshake = Handshake.None;
_serial_port.ReadTimeout = timeout;
_serial_port.DtrEnable = true;
_serial_port.RtsEnable = true;
_serial_port.Open();
_serial_port.DiscardInBuffer();
int totalBytes = _serial_port.BytesToRead;
if (totalBytes > 0)
{
byte[] buffer = new byte[totalBytes];
_serial_port.Read(buffer, 0, totalBytes);
res = ByteArrayToString(buffer);
}
else
{
byte[] buffer = new byte[dataSize];
for (int len = 0; len < buffer.Length;)
{
len += _serial_port.Read(buffer, len, buffer.Length - len);
}
res = ByteArrayToString(buffer);
}
_serial_port.Close();
return res;
}
catch (Exception ex)
{
if (ex is UnauthorizedAccessException || ex is TimeoutException)
{
_serial_port.Close();
}
return ex.ToString();
}
}
我知道还有其他方法可以读取数据:“ReadByte”,“ReadChar”,“ReadExisting”,“ReadLine”和“ReadTo”,但它们都没有用,我做错了吗?
答案 0 :(得分:3)
串口是流设备,可以连续接收数据。只要串口打开,您就需要设置一个定时器,以便不断检查缓冲区中是否有任何内容,并尽快将其复制到磁盘上的缓冲区或文件中,以防止缓冲区溢出。
您需要检查数据内容以找出收到的内容以及收到的所有内容。这取决于发件人。你不能只说收到所有接收的内容,就串口而言,它是一个连续的流。实际数据需要指定协议,启动和停止条件。
修改强>
这是我用来以5mbit /秒的速度通过usb到rs232设备捕获软盘数据的代码片段:
// Capture handler
private void timer2_Tick(object sender, EventArgs e)
{
// Read data from serial port, poll every 10ms
// If data is there, read a block and write it to array
int bytestoread = 0;
//byte buf;
timer2.Stop();
try
{
bytestoread = serialPort1.BytesToRead;
}
catch (InvalidOperationException ex)
{
tbr.Append("Serial connection lost. Exception type:" + ex.ToString());
if ((uint)ex.HResult == 0x80131509)
{
timer2.Stop();
}
}
if (serialPort1.IsOpen)
{
if (bytestoread != 0)
{
bytespersecond += bytestoread;
byte[] temp = new byte[bytestoread];
if (serialPort1.IsOpen)
serialPort1.Read(temp, 0, bytestoread);
tempbuffer.Add(temp);
processing.indexrxbuf += bytestoread;
recentreadbuflength += bytestoread;
//update the scatterplot, this may have a performance hit
processing.rxbuf = tempbuffer.SelectMany(a => a).ToArray();
rxbuf = processing.rxbuf;
if (Setrxbufcontrol == null) return;
Setrxbufcontrol();
}
timer2.Start();
}
}
串口的设置代码。我定义了大缓冲区来防止溢出:
serialPort1.BaudRate = 5000000;
serialPort1.NewLine = "\r\n";
serialPort1.ReceivedBytesThreshold = 500000;
serialPort1.ReadBufferSize = 1048576;
编辑2
从串口读取的步骤: