我用CreateFile函数异步打开串口,然后设置了他的波特率等参数,用ReadFileEx(handle,pBuffer,sizeof(pBuffer),&ReadNum,&rOverLaped,(LPOVERLAPPED_COMPLETION_ROUTINE)lpCompletionRoutine)函数来读串口,
其中初始化定义 OVERLAPPED rOverLaped = {0},定义void lpCompletionRoutine(){};
函数返回的是true,但是ReadNum为0,也就是没有读到数据,GetLastError()也返回0,但没有进入lpCompletionRoutine函数内部执行,
另外,我是用线程里来读串口的,但是这个线程调用读函数一遍后,就不再进入读函数了,是不是线程阻塞之类的,还需要设置什么等待信号之类的吗?
其中初始化定义 OVERLAPPED rOverLaped = {0},定义void lpCompletionRoutine(){};
函数返回的是true,但是ReadNum为0,也就是没有读到数据,GetLastError()也返回0,但没有进入lpCompletionRoutine函数内部执行,
另外,我是用线程里来读串口的,但是这个线程调用读函数一遍后,就不再进入读函数了,是不是线程阻塞之类的,还需要设置什么等待信号之类的吗?
public:
HANDLE hCom; //串口句柄
HANDLE hThread; //线程句柄
DWORD dwThreadID; //线程ID
char DataBuffer[1024]; //接收数据的缓冲区
CString strPath;
CString strText; .cpp
//自定义一个消息
const CM_RECEIVE = WM_USER+100;
OVERLAPPED tOverLaped= {0}; //线程函数使用的OVERLAPPED结构
OVERLAPPED wOverLaped = {0}; //写操作使用的OVERLAPPED结构
OVERLAPPED rOverLaped = {0}; //读操作使用的OVERLAPPED结构
BOOL IsFun = TRUE; //线程是否运行
BOOL IsStop = FALSE; //数据是否发送完毕
---------------------------------------------------------------------------------------------------------OpenPort()//打开串口
{
hCom = CreateFile("COM1", //打开串口1
GENERIC_READ | GENERIC_WRITE, //允许读和写操作
0, //独占方式
NULL,
OPEN_EXISTING, //打开一个存在的串口
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, //异步方式打开
NULL
);if(hCom == INVALID_HANDLE_VALUE)
{
MessageBox("端口打开失败");
}
}
---------------------------------------------------------------------------------------------------------
OnSetport()//设置串口
{
SetupComm(hCom, 1024, 1024); //设置发送和接收缓冲区大小COMMTIMEOUTS TimeOuts;
// 设定读超时
TimeOuts.ReadIntervalTimeout = MAXDWORD;
TimeOuts.ReadTotalTimeoutMultiplier = 0;
TimeOuts.ReadTotalTimeoutConstant = 0;// 设置写超时
TimeOuts.WriteTotalTimeoutMultiplier = 100;
TimeOuts.WriteTotalTimeoutConstant = 500;
SetCommTimeouts(hCom, &TimeOuts); //设置串口信息
DCB dcb;
GetCommState(hCom, &dcb);//获取串口当前配置参数
dcb.BaudRate = 9600;//波特率
dcb.fBinary = TRUE; //允许二进制传输
dcb.fParity = TRUE;//允许奇偶校验
dcb.ByteSize = 8;//数据位
dcb.Parity = NOPARITY;//奇校验
dcb.StopBits = ONESTOPBIT;//1个停止位
if(!SetCommState(hCom,&dcb))
{
MessageBox("设置失败", "提示");
return;
}
if(!SetCommMask(hCom, EV_RXCHAR | EV_TXEMPTY))
{
MessageBox("掩码设置失败", "提示");
return;
}
PurgeComm(hCom, PURGE_TXCLEAR|PURGE_RXCLEAR);DWORD param;
hThread = CreateThread((LPSECURITY_ATTRIBUTES)NULL, //安全属性
0, //初始化线程栈的大小，缺省为与主线程大小相同
(LPTHREAD_START_ROUTINE)ThreadFunction, //线程的全局函数
¶m, //此处传入了主框架的句柄
0, //创建后立即激活
&dwThreadID); //保存新线程的id
if (hThread == INVALID_HANDLE_VALUE)
{
MessageBox("线程创建失败", "提示");
return;
}
}
-----------------------------------------------------------------------------------------------------
DWORD ThreadFunction(LPVOID pParam)//线程函数
{
DWORD dwEvtMask ,dwResult;
// tOverLaped.Internal=0;
// tOverLaped.InternalHigh=0;
tOverLaped.Offset=0;
tOverLaped.OffsetHigh=0;
tOverLaped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);//创建一个事件
while(IsFun)
{
//等待窗口事件
WaitCommEvent(((CMSGCOMDlg*)AfxGetMainWnd())->hCom,
&dwEvtMask, &tOverLaped);
//如果事件没有信号,延时0.1秒
dwResult = WaitForSingleObject(tOverLaped.hEvent, 100);if(dwResult == WAIT_OBJECT_0) //事件对象有信号
{
if(dwEvtMask == EV_RXCHAR) //接收到数据
{
if(IsStop)//发送停止
{
IsStop = FALSE;
//发送消息,由消息处理函数接收数据
::PostMessage(AfxGetMainWnd()->m_hWnd, CM_RECEIVE,
0,(LPARAM)EV_RXCHAR);
}
}
}
}
return 0;
}
-----------------------------------------------------------------------------------------------------OnSend() //发送指令
{
DWORD res;
DWORD factdata = 0;
CString str;
BOOL bwrite;
m_data.GetWindowText(str);
str += "\r";wOverLaped.Offset=0;
wOverLaped.OffsetHigh=0;
wOverLaped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL); //创建一个事件对象
//IsStop = FALSE;
bwrite = WriteFile(hCom, str, str.GetLength(), &factdata, &wOverLaped);
if (bwrite)
{
IsStop = TRUE;
MessageBox("发送成功");
}
else if(GetLastError()==ERROR_IO_PENDING)
{
res = WaitForSingleObject(wOverLaped.hEvent, 2000); //延时2秒,等待数据发送
//如果事件处于有信号状态,表示发送完成
if (WAIT_OBJECT_0 == res) IsStop = TRUE;
else IsStop = FALSE;Sleep(1000); //延时1秒钟}
}
-------------------------------------------------------------------------------------------------------
OnRecieveData(WPARAM wParam, LPARAM lParam)//接收数据
{
DWORD res, factbyte;
DWORD dwBytesRead = 1024;
char DataBuffer[1024]; //初始化数据缓冲区
COMSTAT rst;
ClearCommError(hCom, &res, &rst); //清空串口错误标志,记录当前通信状态
DWORD S=rst.cbInQue;
dwBytesRead = min(dwBytesRead, (DWORD)rst.cbInQue);
// rOverLaped.Internal=0;
// rOverLaped.InternalHigh=0;
rOverLaped.Offset=0;
rOverLaped.OffsetHigh=0;
rOverLaped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL); //创建一个事件对象if (ReadFile(hCom, DataBuffer, dwBytesRead, &factbyte, &rOverLaped)) //读取数据到缓冲区中
{
DataBuffer[rst.cbInQue] = 0;
IsStop = FALSE;
}
else
{
//GetLastError()函数返回ERROR_IO_PENDING,表明串口正在进行读操作
if(GetLastError()==ERROR_IO_PENDING)
{
res = WaitForSingleObject(rOverLaped.hEvent, 2000);
if (WAIT_OBJECT_0 == res) IsStop = FALSE;
}
}
PurgeComm(hCom, PURGE_TXABORT | PURGE_RXABORT | PURGE_TXCLEAR | PURGE_RXCLEAR ); //清空输入、输出缓冲区
//IsStop = FALSE;
CString str = DataBuffer;m_outwnd += str + "\r\n"; //输出到编辑框
UpdateData(FALSE);
}