GPS和PDA的串口通信程序的详细介绍
最近搞了PDA和GPS相结合的一个项目,在写串口程序的时候遇到了一点问题,困饶了好几天都没有解决.最后是因为测试的方法不对引起的.我测试的时候是现在一台机器上面写一个字符串，然后读取他，结果啥都没读到，后来连了串口线进行测试就对了，就是用串口线把计算机和pda连接起来，然后在pda上部署一个简单的测试程序，在计算机上通过串口调试助手不断的发数据，然后pda点接收按纽，哈哈，就有数据了哦！
川口操作的过程实现打开串口，然后读取，然后关闭。
PDA要接收GPS 发来的信息.我用的开发工具是c#.net,compact framework 2003,PDA 模拟器
.net2003并没有提供相应的操作串口的类,所以要自己调用windows的api,具体的代码如下:
using System; using System.Collections; using System.Text; using System.Runtime.InteropServices; using System.Windows.Forms; using System.IO;namespace Port
{ public class Port { public byte[] OutBytes; public byte[] mbytTxBuffer; public int strNum; public string PortNum; public int BaudRate; public byte ByteSize; public byte Parity; // 0-4=no,odd,even,mark,space public byte StopBits; // 0,1,2 = 1, 1.5, 2 public int ReadTimeout; //comm port win32 file handle private int hComm = -1; public bool Opened = false; //win32 api constantsprivate const uint GENERIC_READ = 0x80000000;
private const uint GENERIC_WRITE = 0x40000000; private const int OPEN_EXISTING = 3; private const int INVALID_HANDLE_VALUE = -1;[StructLayout(LayoutKind.Sequential)]
public struct DCB { //taken from c struct in platform sdk public int DCBlength; // sizeof(DCB) public int BaudRate; // 指定当前波特率 current baud rate // these are the c struct bit fields, bit twiddle flag to set public int fBinary; // 指定是否允许二进制模式,在windows95中必须主TRUE binary mode, no EOF check public int fParity; // 指定是否允许奇偶校验 enable parity checking public int fOutxCtsFlow; // 指定CTS是否用于检测发送控制，当为TRUE是CTS为OFF，发送将被挂起。 CTS output flow control public int fOutxDsrFlow; // 指定CTS是否用于检测发送控制 DSR output flow control public int fDtrControl; // DTR_CONTROL_DISABLE值将DTR置为OFF, DTR_CONTROL_ENABLE值将DTR置为ON, DTR_CONTROL_HANDSHAKE允许DTR"握手" DTR flow control type public int fDsrSensitivity; // 当该值为TRUE时DSR为OFF时接收的字节被忽略 DSR sensitivity public int fTXContinueOnXoff; // 指定当接收缓冲区已满,并且驱动程序已经发送出XoffChar字符时发送是否停止。TRUE时，在接收缓冲区接收到缓冲区已满的字节XoffLim且驱动程序已经发送出XoffChar字符中止接收字节之后，发送继续进行。FALSE时，在接收缓冲区接收到代表缓冲区已空的字节XonChar且驱动程序已经发送出恢复发送的XonChar之后，发送继续进行。XOFF continues Tx public int fOutX; // TRUE时，接收到XoffChar之后便停止发送接收到XonChar之后将重新开始 XON/XOFF out flow control public int fInX; // TRUE时，接收缓冲区接收到代表缓冲区满的XoffLim之后，XoffChar发送出去接收缓冲区接收到代表缓冲区空的XonLim之后，XonChar发送出去 XON/XOFF in flow control public int fErrorChar; // 该值为TRUE且fParity为TRUE时，用ErrorChar 成员指定的字符代替奇偶校验错误的接收字符 enable error replacement public int fNull; // eTRUE时，接收时去掉空（0值）字节 enable null stripping public int fRtsControl; // RTS flow control /*RTS_CONTROL_DISABLE时,RTS置为OFF RTS_CONTROL_ENABLE时, RTS置为ON RTS_CONTROL_HANDSHAKE时, 当接收缓冲区小于半满时RTS为ON 当接收缓冲区超过四分之三满时RTS为OFF RTS_CONTROL_TOGGLE时, 当接收缓冲区仍有剩余字节时RTS为ON ,否则缺省为OFF*/ public int fAbortOnError; // TRUE时,有错误发生时中止读和写操作 abort on error public int fDummy2; // 未使用 reserved public uint flags; public ushort wReserved; // 未使用,必须为0 not currently used public ushort XonLim; // 指定在XON字符发送这前接收缓冲区中可允许的最小字节数 transmit XON threshold public ushort XoffLim; // 指定在XOFF字符发送这前接收缓冲区中可允许的最小字节数 transmit XOFF threshold public byte ByteSize; // 指定端口当前使用的数据位 number of bits/byte, 4-8 public byte Parity; // 指定端口当前使用的奇偶校验方法,可能为:EVENPARITY,MARKPARITY,NOPARITY,ODDPARITY 0-4=no,odd,even,mark,space public byte StopBits; // 指定端口当前使用的停止位数,可能为:ONESTOPBIT,ONE5STOPBITS,TWOSTOPBITS 0,1,2 = 1, 1.5, 2 public char XonChar; // 指定用于发送和接收字符XON的值 Tx and Rx XON character public char XoffChar; // 指定用于发送和接收字符XOFF值 Tx and Rx XOFF character public char ErrorChar; // 本字符用来代替接收到的奇偶校验发生错误时的值 error replacement character public char EofChar; // 当没有使用二进制模式时,本字符可用来指示数据的结束 end of input character public char EvtChar; // 当接收到此字符时,会产生一个事件 received event character public ushort wReserved1; // 未使用 reserved; do not use } [StructLayout(LayoutKind.Sequential)] private struct COMMTIMEOUTS { public int ReadIntervalTimeout; public int ReadTotalTimeoutMultiplier; public int ReadTotalTimeoutConstant; public int WriteTotalTimeoutMultiplier; public int WriteTotalTimeoutConstant; } [StructLayout(LayoutKind.Sequential)] private struct OVERLAPPED { public int Internal; public int InternalHigh; public int Offset; public int OffsetHigh; public int hEvent; } [DllImport("coredll.dll")] private static extern int CreateFile( string lpFileName, // 要打开的串口名称 uint dwDesiredAccess, // 指定串口的访问方式，一般设置为可读可写方式 int dwShareMode, // 指定串口的共享模式，串口不能共享，所以设置为0 int lpSecurityAttributes, // 设置串口的安全属性，WIN9X下不支持，应设为NULL int dwCreationDisposition, // 对于串口通信，创建方式只能为OPEN_EXISTING int dwFlagsAndAttributes, // 指定串口属性与标志，设置为FILE_FLAG_OVERLAPPED(重叠I/O操作)，指定串口以异步方式通信 int hTemplateFile // 对于串口通信必须设置为NULL ); [DllImport("coredll.dll")] private static extern int GetCommState( int hFile, //通信设备句柄 ref DCB lpDCB // 设备控制块DCB ); [DllImport("coredll.dll")] private static extern bool BuildCommDCB( string lpDef, // 设备控制字符串 ref DCB lpDCB // 设备控制块 ); [DllImport("coredll.dll")] private static extern bool SetCommState( int hFile, // 通信设备句柄 ref DCB lpDCB // 设备控制块 ); [DllImport("coredll.dll")] private static extern bool GetCommTimeouts( int hFile, // 通信设备句柄 handle to comm device ref COMMTIMEOUTS lpCommTimeouts // 超时时间 time-out values ); [DllImport("coredll.dll")] private static extern bool SetCommTimeouts( int hFile, // 通信设备句柄 handle to comm device ref COMMTIMEOUTS lpCommTimeouts // 超时时间 time-out values ); [DllImport("coredll.dll")] private static extern int ReadFile( int hFile, // 通信设备句柄 handle to file byte[] lpBuffer, // 数据缓冲区 data buffer int nNumberOfBytesToRead, // 多少字节等待读取 number of bytes to read ref int lpNumberOfBytesRead, // 读取多少字节 number of bytes read ref OVERLAPPED lpOverlapped // 溢出缓冲区 overlapped buffer ); [DllImport("coredll.dll")] private static extern bool WriteFile( int hFile, // 通信设备句柄 handle to file byte[] lpBuffer, // 数据缓冲区 data buffer int nNumberOfBytesToWrite, // 多少字节等待写入 number of bytes to write ref int lpNumberOfBytesWritten, // 已经写入多少字节 number of bytes written ref OVERLAPPED lpOverlapped // 溢出缓冲区 overlapped buffer ); [DllImport("coredll.dll")] private static extern bool CloseHandle( int hObject // handle to object ); [DllImport("coredll.dll")] private static extern uint GetLastError(); [DllImport("coredll.dll")] private static extern int PurgeComm(int hFile,int dwFlags);//打开串口的程序；
public void Open() { DCB dcbCommPort = new DCB(); COMMTIMEOUTS ctoCommPort = new COMMTIMEOUTS(); hComm = CreateFile(PortNum, GENERIC_READ | GENERIC_WRITE, 0, 0, OPEN_EXISTING, 0, 0); MessageBox.Show("hComm is :"+hComm); // 如果串口没有打开 if (hComm == INVALID_HANDLE_VALUE) { throw (new ApplicationException("非法操作，不能打开串口！")); } // 设置通信超时时间 SET THE COMM TIMEOUTS. GetCommTimeouts(hComm, ref ctoCommPort); ctoCommPort.ReadTotalTimeoutConstant = ReadTimeout; ctoCommPort.ReadTotalTimeoutMultiplier = 0; ctoCommPort.WriteTotalTimeoutMultiplier = 0; ctoCommPort.WriteTotalTimeoutConstant = 0; SetCommTimeouts(hComm, ref ctoCommPort); // 设置串口 SET BAUD RATE, PARITY, WORD SIZE, AND STOP BITS. GetCommState(hComm, ref dcbCommPort); dcbCommPort.BaudRate = BaudRate; dcbCommPort.flags = 0; dcbCommPort.flags |= 1; if (Parity > 0) { dcbCommPort.flags |= 2; } dcbCommPort.Parity = Parity; dcbCommPort.ByteSize = ByteSize; dcbCommPort.StopBits = StopBits; if (!SetCommState(hComm, ref dcbCommPort)) { throw (new ApplicationException("非法操作，不能打开串口！")); } Opened = true; } public void Close() { if (hComm != INVALID_HANDLE_VALUE) { CloseHandle(hComm); } }//读数据
public byte[] Read(int NumBytes) { byte[] BufBytes = new byte[NumBytes]; if (hComm != INVALID_HANDLE_VALUE) { OVERLAPPED ovlCommPort = new OVERLAPPED(); int BytesRead = 0; ReadFile(hComm, BufBytes, NumBytes, ref BytesRead, ref ovlCommPort); OutBytes = new byte[BytesRead]; Array.Copy(BufBytes,0,OutBytes,0,BytesRead); strNum = BytesRead; } else { throw (new ApplicationException("串口未打开！")); } MessageBox.Show("OutBytes.length is :"+OutBytes.Length); return OutBytes;} //来源自.net compact framework 技术内幕第11章串行通信第347页
//用的就是这个方法来读的
public string Input(int BytesToRead)
{ string result=""; int intResult; ASCIIEncoding objEncoder=new ASCIIEncoding(); int lpNumberOfBytesRead=0; OVERLAPPED lpOverlapped; if(BytesToRead==0) BytesToRead=512; if(hComm!=-1) { OutBytes=new byte[BytesToRead]; lpOverlapped=new OVERLAPPED(); intResult=ReadFile(hComm, OutBytes, BytesToRead, ref lpNumberOfBytesRead, ref lpOverlapped); if(intResult==0) { hComm=-1; throw (new ApplicationException("串口未打开！"));}
else { result=objEncoder.GetString(OutBytes,0,BytesToRead); MessageBox.Show("result is :"+result);}
}
return result; }//这个方法是把数据写到串口上的，来源自.net compact framework 技术内幕第11章串行通信第347页
//没有用到这个方法暂时
public void Output(string Value) { int lpNumberOfBytesWritten=0; OVERLAPPED lpOverlapped=new OVERLAPPED(); ASCIIEncoding objEncoder=new ASCIIEncoding(); MessageBox.Show("hComm is :"+hComm); if(hComm!=-1) { mbytTxBuffer=new byte[Value.Length]; mbytTxBuffer=objEncoder.GetBytes(Value); bool m_boo=false; m_boo=WriteFile(hComm,mbytTxBuffer,mbytTxBuffer.Length,ref lpNumberOfBytesWritten,ref lpOverlapped); if(m_boo==true) { MessageBox.Show("写成功了"); } else { MessageBox.Show("没有成功！!"); } } }// 这个方法也是写数据到串口的
public void Write(byte[] WriteBytes) { if (hComm != INVALID_HANDLE_VALUE) { OVERLAPPED ovlCommPort = new OVERLAPPED(); int BytesWritten = 0; WriteFile(hComm, WriteBytes, WriteBytes.Length, ref BytesWritten, ref ovlCommPort); } else { throw (new ApplicationException("串口未打开！")); } } }public class HexCon
{ // 把十六进制字符串转换成字节型和把字节型转换成十六进制字符串 converter hex string to byte and byte to hex string public static string ByteToString(byte[] InBytes) { string StringOut = ""; foreach (byte InByte in InBytes) { StringOut = StringOut + String.Format("{0:X2} ", InByte); } return StringOut; }public static byte[] StringToByte(string InString)
{ string[] ByteStrings; ByteStrings = InString.Split(" ".ToCharArray()); byte[] ByteOut; ByteOut = new byte[ByteStrings.Length]; for (int i = 0; i <= ByteStrings.Length - 1; i++) { ByteOut[i] = Convert.ToByte(ByteStrings[i], 16); } return ByteOut; } } }