vc++ 串口编程

用vc++编写上位机：

 

一是利用Windows API通信函数；二是利用VC的标准通信

函数inp、inpw、inpd、outp、outpw、outpd等直接对串口进行操作；三是使用Microsoft Visual C++的通信控件（MSComm）；

四是利用第三方编写的通信类。以上几种方法中第一种使用面较广，但由于比较复杂，专业化程度较高，使用较困难；第二种需要了

解硬件电路结构原理；第三种方法看来较简单，只需要对串口进行简单配置，但是由于使用令人费解的VARIANT 类，使用也不是很容

易；第四种方法是利用一种用于串行通信的CSerial类（这种类是由第三方提供），只要理解这种类的几个成员函数，就能方便的使

用。

  1.初始化时应注意CreateFile()函数中串口共享方式应设为0，串口为不可共享设备，其它与一般文件读写类似。以下给出API实

现的源代码。

1.1 发送的例程

//声明全局变量

HANDLE m_hIDComDev；

OVERLAPPED m_OverlappedRead, m_Over lappedWrite;

//初始化串口

void CSerialAPIView::OnInitialUpdate()

{

CView::OnInitialUpdate();

Char szComParams[50];

DCB dcb;

Memset(&m_OverlappedRead, 0, sizeof (OVERLAPPED));

Memset(&m_OverlappedWrite, 0, sizeof (OVERLAPPED));

m_hIDComDev = NULL;

m_hIDComDev = CreateFile(“COM2”, GENERIC_READ│GENERIC_WRITE, 0, NULL,

OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL│FILE_FLAG_OVERLAPPED, NULL);

if (m_hIDComDev == NULL)

{

AfxMessageBox(“Can not open serial port!”);

goto endd;

}

memset(&m_OverlappedRead, 0, sizeof (OVERLAPPED));

memset(&m_OverlappedWrite, 0, sizeof (OVERLAPPED));

COMMTIMEOUTS CommTimeOuts;

CommTimeOuts.ReadIntervalTimeout=0×FFFFFFFF;

CommTimeOuts.ReadTotalTimeoutMultiplier = 0;

CommTimeOuts.ReadTotalTimeoutConstant = 0;

CommTimeOuts.WriteTotalTimeoutMultiplier = 0;

CommTimeOuts.WriteTotalTimeoutConstant = 5000;

SetCommTimeouts(m_hIDComDev, &CommTimeOuts);

Wsprintf(szComparams, “COM2:9600, n, 8, 1”);

m_OverlappedRead. hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);

m_OverlappedWrite. hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);

dcb. DCBlength = sizeof(DCB);

GetCommState(m_hIDComDev, &dcb);

dcb. BaudRate = 9600;

dcb. ByteSize= 8;

unsigned char ucSet;

ucSet = (unsigned char) ((FC_RTSCTS&FC_DTRDSR) != 0);

ucSet = (unsigned char) ((FC_RTSCTS&FC_RTSCTS) ! = 0);

ucSet = (unsigned char) ((FC_RTSCTS&FC_XONXOFF) ! = 0);

if (!SetCommState(m_hIDComDev, &dcb)‖

!SetupComm(m_hIDComDev,10000,10000)‖

m_OverlappedRead. hEvent ==NULL‖

m_OverlappedWrite. hEvent ==NULL)

{

DWORD dwError = GetLastError();

if (m_OverlappedRead. hEvent != NULL)

CloseHandle(m_OverlappedRead. hEvent);

if (m_OverlappedWrite. hEvent != NULL)

CloseHandle(m_OverlappedWrite. hEvent);

CloseHandle(m_hIDComDev);

}

endd:

;

}

//发送数据

void CSerialAPIView::OnSend()

{

char szMessage[20] = “thank you very much”;

DWORD dwBytesWritten;

for (int i=0; i<sizeof(szMessage); i++)

{

WriteFile(m_hIDComDev, (LPSTR)&szMessage[i], 1, &dwBytesWritten, &m_OverlappedWrite);

if (WaitForSingleObject(m_OverlapperWrite, hEvent, 1000))dwBytesWritten = 0;

else

{

GentOverlappedResult(m_hIDComDev, &m_OverlappedWrite, &dwBytesWritten, FALSE);

m_OverlappedWrite. Offset += dwBytesWritten;

}

dwBytesWritten++;

}

}

1.2 接收例程

DCB ComDcb; //设备控制块

HANDLE hCom; //global handle

hCom = CreateFile ("COM1",GENERIC_READ| GENERIC_WRITE,0,NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,NULL);

if (hCom==INVALID_HANDLE_VALUE)

{

AfxMessageBox("无法打开串行口");

}

else

{

COMMTIMEOUTS CommTimeOuts ;

SetCommMask(hCom, EV_RXCHAR ) ;

SetupComm(hCom, 4096, 4096 ) ; /*设置收发缓冲区 尺寸为4K */

PurgeComm(hCom, PURGE_TXABORT| PURGE_RXABORT | PURGE_TXCLEAR| PURGE_RXCLEAR ) ; //清收发缓冲区

//以下初始化结构变量CommTimeOuts, 设置超时参数 CommTimeOuts.ReadIntervalTimeout = 0×FFFFFFFF ;

CommTimeOuts.ReadTotalTimeoutMultiplier = 0;

CommTimeOuts.ReadTotalTimeoutConstant = 4000;

CommTimeOuts.WriteTotalTimeoutMultiplier = 0;

CommTimeOuts.WriteTotalTimeoutConstant =