編程原理
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程序1為查詢通信方式接口程序，為一典型的數(shù)據(jù)采集例程。其中bioscom()函數(shù)初始化COM1(此函數(shù)實際調(diào)用BIOS
INT
14H中斷0號功能)。這樣在程序中就避免了具體設(shè)置波特率因子等繁瑣工作，只需直接訪問發(fā)送/接收寄存器(3F8H)和線路狀態(tài)寄存
#include reg51.h
#include intrins.h
unsigned char key_s, key_v, tmp;
char code str[] = "welcome!??\n\r";
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工作于8位自動重載模式, 用于產(chǎn)生波特率
TH1 = 0xFD; // 波特率9600
TL1 = 0xFD;
SCON = 0x50; // 設(shè)定串行口工作方式
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(shù)據(jù)到來
{
RI = 0;
tmp = SBUF; // 暫存接收到的數(shù)據(jù)
P0 = tmp; // 數(shù)據(jù)傳送到P0口
send_char(tmp); // 回傳接收到的數(shù)據(jù)
}
}
}
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)
// 傳送一個字符
{
SBUF = txd;
while(!TI); // 等特數(shù)據(jù)傳送
TI = 0; // 清除數(shù)據(jù)傳送標(biāo)志
}
void send_str()
// 傳送字串
{
unsigned char i = 0;
while(str[i] != '\0')
{
SBUF = str[i];
while(!TI); // 等特數(shù)據(jù)傳送
TI = 0; // 清除數(shù)據(jù)傳送標(biāo)志
i++; // 下一個字符
}
}
void delayms(unsigned char ms)
// 延時子程序
{
unsigned char i;
while(ms--)
{
for(i = 0; i 120; i++);
}
}
拓展資料
C語言是一門通用計算機編程語言，應(yīng)用廣泛。C語言的設(shè)計目標(biāo)是提供一種能以簡易的方式編譯、處理低級存儲器、產(chǎn)生少量的機器碼以及不需要任何運行環(huán)境支持便能運行的編程語言。
盡管C語言提供了許多低級處理的功能，但仍然保持著良好跨平臺的特性，以一個標(biāo)準(zhǔn)規(guī)格寫出的C語言程序可在許多電腦平臺上進(jìn)行編譯，甚至包含一些嵌入式處理器（單片機或稱MCU）以及超級電腦等作業(yè)平臺。
二十世紀(jì)八十年代，為了避免各開發(fā)廠商用的C語言語法產(chǎn)生差異，由美國國家標(biāo)準(zhǔn)局為C語言制定了一套完整的美國國家標(biāo)準(zhǔn)語法，稱為ANSI C，作為C語言最初的標(biāo)準(zhǔn)。目前2011年12月8日，國際標(biāo)準(zhǔn)化組織（ISO）和國際電工委員會（IEC）發(fā)布的C11標(biāo)準(zhǔn)是C語言的第三個官方標(biāo)準(zhǔn)，也是C語言的最新標(biāo)準(zhǔn)，該標(biāo)準(zhǔn)更好的支持了漢字函數(shù)名和漢字標(biāo)識符，一定程度上實現(xiàn)了漢字編程。
我寫的串口通信代碼比較長，給幾個關(guān)鍵函數(shù)你吧，可實現(xiàn)PC與單片機的雙工通信
/*串口通訊 單片機晶振：11.0592MHz
T1工作于方式2 波特率=2^smod*fosc/32/12/(256-X)*/
#includecommon.h
void do_uart(void); //串口接收執(zhí)字符時的操作
/*串口發(fā)送字符串 */
void sendstr(uchar *p)
{
while(*p!='\0')
{ SBUF=*p; //待發(fā)送的數(shù)據(jù)寫入緩沖區(qū)
while(!TI); //等待發(fā)送完成
TI=0; //清零發(fā)送標(biāo)志位
p++; //指針加1
cnt_s++; //發(fā)送計數(shù)
}
}
/*串口接收中斷函數(shù)*/
void int_rec(void) interrupt 4 using 2
{
if(RI) //查詢接收標(biāo)志位（有數(shù)據(jù)發(fā)送過來時置為1）
{
RI = 0; //接收標(biāo)志位清零
// sendchar(SBUF);//讓從電腦上傳到單片機的數(shù)據(jù)，傳回的電腦顯示
do_uart();//對接受到得字符操作
}
}
/*串口初始化*/
void com_init(uint baud)
{
SCON = 0x50; //串口工作方式為1，串行允許接受
TMOD = 0x21; //定時器1工作在方式2 定時器0工作在方式1
//PCON = 0x80; //SMOD = 1; 波特率加倍
TH1=256-fosc/32/12/baud;
TL1=TH1;
ES = 1; //開串口中斷
TR1 = 1; //允許定時器1工作
EA = 1; //開總中斷
}
void sendchar(uchar uart_dat) //串口發(fā)送字符函數(shù)
{
SBUF = uart_dat; //待發(fā)送的數(shù)據(jù)寫入緩沖區(qū)
while(!TI); //等待發(fā)送完成
TI = 0; //清零發(fā)送標(biāo)志位
cnt_s++; //發(fā)送計數(shù)
}
C語言會有操作串口的庫函數(shù)的，按照串口庫函數(shù)標(biāo)識實現(xiàn)調(diào)用就可以了。
基本方法是使用CreateFile來建立一個串口文件，然后用overlap的方式進(jìn)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(fā)送數(shù)據(jù)
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(guān)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(shù)據(jù)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，并返回串口句柄
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(yīng)該是 \\.\COMXX
//打開窗口其實就是創(chuàng)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(shè)置一些COM口通訊參數(shù)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(jiān)視串口數(shù)據(jù)，一旦有數(shù)據(jù)則讀取并調(diào)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(dwEvtMaskEV_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(dwTotalLen0)
{
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_MAXdwReadLen)?dwReadLen:SERAIL_PORT_BUF_MAX;
}
if(pUsbSrv-m_pRspCmdFunc!=NULLnReadBufLen!=0)
{
pUsbSrv-m_pRspCmdFunc(pUsbSrv-m_hParseApp, (char*)pBuf,nReadBufLen);
}
delete pBuf;
ClearCommError(hComPort, dwErrorFlags, ComStat );
int len =0;//= m_retList.GetSize();
}//endif if(dwEvtMaskEV_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(dwByteswrittenTotalnLennSentTimes10)
{
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(dwByteswrittenTotalnLen)
return 0;
else
return 1;
}
貼上來的程序部分，修改如下：
#includereg52.h
#includestdio.h //打印到串口函數(shù)
#define uchar unsigned char
#define uint unsigned int
uchar date_zi[4][11]; //存放接收到的數(shù)據(jù)
uint i_index=0; //接收到的字符個數(shù)
uint i=0; //i字符用于循環(huán)
unsigned int xia = 0; //用于保存到數(shù)據(jù)的下標(biāo)
void fh_zi(uchar a) //返回字符到串口
{
ES=0;
SBUF=a;
while(!TI);
TI=0;
ES=1;
}
void init()
{
TMOD=0x20;
TH1=0xfd;
TL1=0Xfd;
//TH0=(65536-45872)/256;
//TL0=(65536-45872)%256;
TR1=1;
SM0=0;
SM1=1;
REN=1;
EA=1;
ES=1;
}
void main()
{
i_index=0;
xia=2;
init();
while(1);
}
void ser() interrupt 4 //串口
{
if(RI == 1)
{
RI=0;
date_zi[xia][i_index] = SBUF;
i_index++;
if(i_index10) //接受完10個字符后顯示數(shù)組所有內(nèi)容
{
i_index=0;
for(i=0;i11;i++) //顯示數(shù)組中所有內(nèi)容
fh_zi(date_zi[0][i]);
for(i=0;i11;i++)
fh_zi(date_zi[1][i]);
for(i=0;i11;i++)
fh_zi(date_zi[2][i]);
for(i=0;i11;i++)
fh_zi(date_zi[3][i]);
}
}
}
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