『壹』 用c語言讀取串口數據
調用輸入輸出的函數,它的參數大概是埠地址和緩沖區(好像是哈,TC2.0里是有的,好像是input,其它版本的C也應該有類似的函數)——跟windows裡面的deviceiocontrol()很類似的,
調用它就可以啦
當然你要先把串口設置好,比如波特率之類的
『貳』 windows下C語言怎麼對串口進行讀寫操作
windows下對串口的操作可以通過WindowsAPI進行,也可以通過Linux下的read什麼的直接操作,但是這種情況需要了解電路結構,比較麻煩,第三種有第三方提供的庫,但是大多數針對C++,所以可能比較難找到順手的第三方庫.
那麼,接下來就見要介紹一下串口通信用WindowsAPI通信的方式.
我們會發現,在文件名的位置填上"comX" X表示com口號,超過十的com口號需要另外的書寫方式,這里不說了,因為網上一抓一大把,接下來,我們要對串口進行一系列的明確設置,這里就用到了一個結構體DCB結構,是專門用來描述一個com口的工作方式的,由於次結構體有28個成員,非常多,而且大部分的設置都是全世界通用的,所以,我們偷個懶,在打開一個com口之後,建立DCB結構體,接下來調用一個函數GetCommState用這個函數把現在com口的數據都寫到DCB里,這樣,比較通用的com口設置就已經弄好了,我們一般情況下只需要改一下DCB的波特率就好了,改好後馬上用SetCommState把剛改好的結構體再寫回去,這樣串口就設置好了,現在還有點麻煩,串口設置好了,我們要它干什麼呢?廢話,讀寫數據唄,嘟~~~~~~可不能用fwrite和fread因為這個com口句柄不是文件句柄,是內核句柄,要用ReadFile和WriteFile來進行讀寫,又出麻煩了,我們怎麼知道單片機什麼時候發數據過來,就算我們知道,計算機什麼時候知道啊?所以,一般的情況下,用ReadFile一直在哪檢查,又是麻煩,通常情況下,一個com口的ReadFile設置是阻塞函數,影響編程啊!!!!!!
怎麼辦,很簡單,你不阻塞嗎,打通你唄,我們再建立里一個結構體COMMTIMEOUTS這個結構體描述里一個com口的相關超時設置,我們用GetCommTimeouts把數據讀回來,具體的設置方法在網上也有,但是要注意,有一個MAXDWORD用它來設置讀間隔超時設置就可以使ReadFile向kbhit()函數一樣完全非阻塞了.
經過一些列的設置,事實上,現在已經可以通信了,要是有人覺得緩存不舒服,用SetupComm函數來重設緩存大小,對於傳輸速度比較快的通信,要把緩存設置的大些.
『叄』 windows下怎麼用C語言讀取串口裡的數據
Windows下的語言讀取串口的數據,可以通過USB的一些特定連接。
『肆』 c語言 讓計算機像單片機一樣接收串口發來的數據
可以使用串口助手軟體,或者自己編定軟體,VB、VC的編程使用MSCOMM控制項實現串口通信,但是如果是與下位機通信光有上位機軟體是不行的,還要有與下位機連接的串口線,但是電腦串口線不能與下位機直接連接,因為計算機採用負邏輯,需要使用MAX232或者其他電平轉換晶元轉換電平後才能與下位機進行串口通信
『伍』 如何用C語言控制計算機串口
基本方法是使用CreateFile來建立一個串口文件,然後用overlap的方式進行讀寫
#define SERAIL_PORT_BUF_MAX (1024*8)
typedef HRESULT (*PFN_CMD_PARSE_DATA)(HANDLE hParseApp, LPCSTR szRspCmd, int nCmdLen);
class CUsbSrvApp// : public CWinApp
{
public:
CUsbSrvApp();
~CUsbSrvApp();
BOOL OnSendData(const char *szBuf, int nLen);// 發送數據
int ComConnect(CString strPort); // 連接COM口
HANDLE OpenComPort(CString strPort, int nBaudRate, int nDataBits, int nStopBits, int nParity, int nFlowCtrlType); // 打開串口
void Close(); // 關閉串口
HANDLE m_hCom;
BOOL m_bConnected;
OVERLAPPED m_OverlappedRead;
OVERLAPPED m_OverlappedWrite;
CWinThread *m_pThread;
PFN_CMD_PARSE_DATA m_pRspCmdFunc; // 用來處理接受數據的CALLBACK
HANDLE m_hParseApp;
};
CUsbSrvApp::CUsbSrvApp()
{
// TODO: add construction code here,
// Place all significant initialization in InitInstance
m_bConnected = false;
m_hCom = NULL;
m_pRspCmdFunc = NULL;
}
CUsbSrvApp::~CUsbSrvApp()
{
}
//打開串口通信,並返回串口句柄
HANDLE CUsbSrvApp::OpenComPort(CString strPortName,
int nBaudRate,
int nDataBits,
int nStopBits,
int nParity,
int nFlowCtrlType)
{
DCB dcb;
COMMTIMEOUTS CommTimeOuts ;
COMMCONFIG ComConfig;
HANDLE hComPort;
CString strPort;
strPort.Format("\\\\.\\%s",strPortName); // COM口的文件名應該是 \\.\COMXX
//打開窗口其實就是創建一個文件
hComPort = CreateFile(strPort,
GENERIC_READ | GENERIC_WRITE,
FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL|FILE_FLAG_OVERLAPPED,
NULL);
if (INVALID_HANDLE_VALUE == hComPort)
return INVALID_HANDLE_VALUE;
// 設置一些COM口通訊參數和OVERLAP
CommTimeOuts.ReadIntervalTimeout = -1;
CommTimeOuts.ReadTotalTimeoutConstant = 0;
CommTimeOuts.ReadTotalTimeoutMultiplier = 0;
CommTimeOuts.WriteTotalTimeoutConstant = 0;
CommTimeOuts.WriteTotalTimeoutMultiplier = 0x1388;
SetCommTimeouts( m_hCom, &CommTimeOuts ) ;
SetDefaultCommConfig(strPortName, &ComConfig, sizeof(COMMCONFIG));
GetCommState(m_hCom, &dcb ) ;
dcb.BaudRate = nBaudRate;
dcb.ByteSize = nDataBits;
dcb.StopBits = nStopBits;
dcb.fParity = (NOPARITY != nParity);
dcb.Parity = nParity;
//set the receive char
dcb.EvtChar = 0x0D;
switch(nFlowCtrlType)
{
case 0: //no flow control
break;
case 1://HARD_FLOW_CTRL:
dcb.fOutxCtsFlow = TRUE;
dcb.fOutxDsrFlow = TRUE;
dcb.fDtrControl = DTR_CONTROL_DISABLE;
dcb.fDsrSensitivity = TRUE;
dcb.fRtsControl = RTS_CONTROL_TOGGLE;
break;
case 2://SOFT_FLOW_CTRL:
dcb.fOutX = TRUE;
dcb.fInX = TRUE;
break;
}
BuildCommDCB(_T("baud=115200 parity=N data=8 stop=1"),&dcb);
SetCommState(hComPort, &dcb ) ;
SetCommMask(hComPort, 0);
SetCommMask(hComPort, EV_RXCHAR|EV_CTS|EV_DSR|EV_RLSD|EV_RING);
SetupComm( hComPort, SERAIL_PORT_BUF_MAX,SERAIL_PORT_BUF_MAX) ;
//clear read and write buffer
PurgeComm( hComPort, PURGE_TXABORT | PURGE_RXABORT | PURGE_TXCLEAR | PURGE_RXCLEAR );
return hComPort;
}
void CUsbSrvApp::Close()
{
if(m_bConnected)
{
m_bConnected = false;
CloseHandle(m_hCom);
m_hCom = NULL;
}
}
// 這個線程是監視串口數據,一旦有數據則讀取並調用CALLBACK通知客戶端
UINT ReceiveComData(LPVOID pParam)
{
CUsbSrvApp *pUsbSrv = (CUsbSrvApp *)pParam;
HANDLE hComPort = pUsbSrv->m_hCom;
DWORD dwEvtMask=0;
DWORD dwErrorFlags;
SetCommMask( hComPort, EV_RXCHAR);
OVERLAPPED osRead;
osRead.hEvent = CreateEvent(NULL,FALSE,FALSE,NULL);
DWORD dwTransfer = 0;
while(pUsbSrv->m_bConnected)
{
if( !WaitCommEvent( hComPort, &dwEvtMask,&osRead))
{
if( GetLastError()== ERROR_IO_PENDING)
{
WaitForSingleObject(osRead.hEvent, INFINITE);
if(dwEvtMask&EV_RXCHAR==EV_RXCHAR)
{
COMSTAT ComStat={0} ;
DWORD dwReadLen = 0;
DWORD dwBytesRead = 0;
DWORD dwTotalLen = 0;
ClearCommError(hComPort, &dwErrorFlags, &ComStat );
dwTotalLen = ComStat.cbInQue;
dwReadLen = (SERAIL_PORT_BUF_MAX > dwTotalLen)?dwTotalLen:SERAIL_PORT_BUF_MAX;
BYTE *pBuf = new BYTE[dwTotalLen+1];
memset(pBuf, 0 , dwTotalLen+1);
DWORD nReadBufLen=0;
while(dwTotalLen>0)
{
if(FALSE == ReadFile( hComPort, pBuf+nReadBufLen,dwReadLen, &dwBytesRead,&pUsbSrv->m_OverlappedRead))
{
if(GetLastError() == ERROR_IO_PENDING)
{
GetOverlappedResult(hComPort,&osRead, &dwTransfer, TRUE );
}
break;
}
nReadBufLen +=dwBytesRead;
dwTotalLen -=dwBytesRead;
dwReadLen -= dwBytesRead;
dwReadLen = (SERAIL_PORT_BUF_MAX>dwReadLen)?dwReadLen:SERAIL_PORT_BUF_MAX;
}
if(pUsbSrv->m_pRspCmdFunc!=NULL&&nReadBufLen!=0)
{
pUsbSrv->m_pRspCmdFunc(pUsbSrv->m_hParseApp, (char*)pBuf,nReadBufLen);
}
delete pBuf;
ClearCommError(hComPort, &dwErrorFlags, &ComStat );
int len =0;//= m_retList.GetSize();
}//endif if(dwEvtMask&EV_RXCHAR==EV_RXCHAR)
}//endif if( GetLastError()== ERROR_IO_PENDING)
}//endif if( !WaitCommEvent( hComPort, &dwEvtMask,&o))
else
{
if(GetLastError() == ERROR_IO_PENDING) {
GetOverlappedResult(hComPort, &osRead, &dwTransfer, TRUE ); // sleep thread
}
}
Sleep(1);
} //endwhile while(m_bConnected)
return 0;
}
int CUsbSrvApp::ComConnect(CString strPort)
{
int nBaudRate = 115200;
int nDataBits = 8;
int nStopBits = 1;
int nParity = 0;
int nFlowCtrl = 1;
if (NULL != m_hCom || m_bConnected)
{
return 0;
}
m_hCom = OpenComPort(strPort,nBaudRate,nDataBits,nStopBits,nParity,nFlowCtrl);
if( INVALID_HANDLE_VALUE == m_hCom)
{
m_hCom = NULL;
return 0;
}
memset( &m_OverlappedRead, 0, sizeof( OVERLAPPED ) );
memset( &m_OverlappedWrite, 0, sizeof( OVERLAPPED ) );
m_OverlappedRead.hEvent = CreateEvent( NULL, TRUE, FALSE, NULL );
m_OverlappedWrite.hEvent = CreateEvent( NULL, TRUE, FALSE, NULL );
m_pThread = AfxBeginThread( ReceiveComData,(void*)this,THREAD_PRIORITY_NORMAL,0,CREATE_SUSPENDED ,NULL );
if( NULL == m_pThread )
{
CloseHandle( m_hCom );
m_hCom = NULL;
return FALSE;
}
else
{
m_bConnected = TRUE;
m_pThread->ResumeThread( );
}
return TRUE;
}
int CUsbSrvApp::OnSendData(const char *szBuf, int nLen)
{
BOOL bWriteStat;
BOOL bWrite = TRUE;
DWORD dwBytesWrite = 0;
DWORD dwBytesWritten = 0;
int dwByteswrittenTotal = 0;
if (NULL == m_hCom)
return 0;
int nSentTimes=0;
while(dwByteswrittenTotal<nLen&&nSentTimes<10)
{
nSentTimes++;
dwBytesWrite = nLen-dwByteswrittenTotal;
bWriteStat = WriteFile( m_hCom, szBuf+dwByteswrittenTotal, dwBytesWrite, &dwBytesWritten, &m_OverlappedWrite );
if( !bWriteStat)
{
if ( GetLastError() == ERROR_IO_PENDING )
{
dwBytesWritten = 0;
bWrite = FALSE;
}
}
if (!bWrite)
{
bWrite = TRUE;
bWriteStat = GetOverlappedResult(m_hCom, // Handle to COMM port
&m_OverlappedWrite, // Overlapped structure
&dwBytesWritten, // Stores number of bytes sent
TRUE); // Wait flag
//deal with the error code
}
dwByteswrittenTotal += dwBytesWritten;
}
if(dwByteswrittenTotal<nLen)
return 0;
else
return 1;
}
『陸』 c語言怎麼實現串口通信
編程原理
程序1為查詢通信方式介面程序,為一典型的數據採集常式。其中bioscom()函數初始化COM1(此函數實際調用BIOS
INT
14H中斷0號功能)。這樣在程序中就避免了具體設置波特率因子等繁瑣工作,只需直接訪問發送/接收寄存器(3F8H)和線路狀態寄存
『柒』 C語言變成實現串口收發數據
#include <reg51.h>
#include <intrins.h>
unsigned char key_s, key_v, tmp;
char code str[] = "welcome!www.willar.com
";
void send_str();
bit scan_key();
void proc_key();
void delayms(unsigned char ms);
void send_char(unsigned char txd);
sbit K1 = P1^4;
main()
{
TMOD = 0x20; // 定時器1工作於8位自動重載模式, 用於產生波特率
TH1 = 0xFD; // 波特率9600
TL1 = 0xFD;
SCON = 0x50; // 設定串列口工作方式
PCON &= 0xef; // 波特率不倍增
TR1 = 1; // 啟動定時器1
IE = 0x0; // 禁止任何中斷
while(1)
{
if(scan_key()) // 掃描按鍵
{
delayms(10); // 延時去抖動
if(scan_key()) // 再次掃描
{
key_v = key_s; // 保存鍵值
proc_key(); // 鍵處理
}
}
if(RI) // 是否有數據到來
{
RI = 0;
tmp = SBUF; // 暫存接收到的數據
P0 = tmp; // 數據傳送到P0口
send_char(tmp); // 回傳接收到的數據
}
}
}
bit scan_key()
// 掃描按鍵
{
key_s = 0x00;
key_s |= K1;
return(key_s ^ key_v);
}
void proc_key()
// 鍵處理
{
if((key_v & 0x01) == 0)
{ // K1按下
send_str(); // 傳送字串"welcome!...
}
}
void send_char(unsigned char txd)
// 傳送一個字元
{
SBUF = txd;
while(!TI); // 等特數據傳送
TI = 0; // 清除數據傳送標志
}
void send_str()
// 傳送字串
{
unsigned char i = 0;
while(str[i] != '