C＃无法从串口Arduino读取完整缓冲区

Question

我已将Arduino连接到串行端口。 Arduino具有以下简单的代码来发送字节：

void setup()
{
    Serial.begin(9600);
}

void loop()
{
    Serial.write((char)100);
}

接收字节的代码（在单独的线程中）：

int buffersize = 100000;
byte[] buffer = new byte[buffersize];

SerialPort port = new SerialPort("COM3", 9600);
port.ReadBufferSize = buffersize;
port.Open();

int bytesread = 0;
do
{
    bytesread = port.BytesToRead;
}
while(bytesread < buffersize && bytesread != buffersize);

port.Read(buffer, 0, buffersize);

我读到BytesToRead可以返回比ReadBufferSize更多的值，因为它包含一个以上的缓冲区。 但是相反，我只能接收将近12000，并且此后ReadBufferSize不变。 所有波特率都出现相同的问题。

那么如何一次读取缓冲区中的所有100000字节？ 也许有一些驱动程序设置等？ 请帮忙。

Answer 1

如果Arduino以这种波特率连续发送字节，则速度将最大为9600/10 = 960字节/秒（1字节将占用10个波特：8个数据位+ 1个开始+ 1个停止）。 然后将在104秒内收集100000字节。 如果通信没有中断，则您的代码应该可以工作。 要调试它，可以在while循环中添加它：

System.Threading.Thread.Sleep(1000); //sleep 1 second
Console.WriteLine("Total accumulated = " + bytesread);

但是，更好的方法是使用SerialPort的DataReceived事件：

int buffersize = 100000;
SerialPort port = new SerialPort("COM3", 9600);

port.DataReceived += port_DataReceived;

// To be safe, set the buffer size as double the size you want to read once
// This is for the case when the system is busy and delays the event processing
port.ReadBufferSize = 2 * buffersize;

// DataReceived event will be fired when in the receive buffer
// are at least ReceivedBytesThreshold bytes
port.ReceivedBytesThreshold = buffersize; 
port.Open();

事件处理程序：

private void port_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
    // The event will also be fired for EofChar (byte 0x1A), ignore it
    if (e.EventType == SerialData.Eof)
        return;

    // Read the BytesToRead value, 
    // don't assume it's exactly ReceivedBytesThreshold
    byte[] buffer = new byte[port.BytesToRead];
    port.Read(buffer, 0, buffer.Length);

    // ... Process the buffer ...
}