几个问题：（串口）

Question

1：串口通讯几种方法？
2:我怎样实现？比较简单的

Answer 1

一般有三种：
1.MSCOMM 这时Ms的控件，比较容易，但不是很灵活，需要注册！
2.API的CreateFile，readFile，WriteFile 比较灵活，难度中等！
3.C＋汇编这个一般使用高级用户，难度较大。给你我的一个项目的API：
// TSerial.cpp: implementation of the TSerial class.
//
//////////////////////////////////////////////////////////////////////#include "stdafx.h"
#include "ECS.h"
#include "TSerial.h"#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////
TSerial::TSerial()
{
    m_bOpened=false;
}TSerial::~TSerial()
{}
bool TSerial::Open(int nPort,int nBand,int nByteSize)
{
if(m_bOpened)
    return true;
char szPort[15];
CString Er;
DCB dcb;
wsprintf(szPort,"COM%d",nPort);
m_hCommDev=CreateFile(szPort,GENERIC_READ|GENERIC_WRITE,0,NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL|FILE_FLAG_OVERLAPPED,NULL);
if(m_hCommDev==NULL)
return false;
memset(&m_OverlappedRead,0,sizeof(OVERLAPPED));
memset(&m_OverlappedWrite,0,sizeof(OVERLAPPED));
COMMTIMEOUTS CommTimeOuts;
CommTimeOuts.ReadIntervalTimeout=0xFFFFFFFF;
    CommTimeOuts.ReadTotalTimeoutMultiplier=0;
CommTimeOuts.ReadTotalTimeoutConstant=0;
CommTimeOuts.WriteTotalTimeoutConstant=1000;
CommTimeOuts.WriteTotalTimeoutMultiplier=0;
SetCommTimeouts(m_hCommDev,&CommTimeOuts); m_OverlappedRead.hEvent=CreateEvent(NULL,true,false,NULL);
m_OverlappedWrite.hEvent=CreateEvent(NULL,true,false,NULL); dcb.DCBlength=sizeof(DCB);
GetCommState(m_hCommDev,&dcb);
dcb.BaudRate=nBand;
dcb.ByteSize=nByteSize;
if(!SetCommState(m_hCommDev,&dcb)||!SetupComm(m_hCommDev,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_hCommDev);
Er.Format("%d",dwError);
        MessageBox(NULL,Er,"提示",MB_OK);
return false;
}
m_bOpened=true;
return m_bOpened;
}
DWORD TSerial::ReadData(void *buffer,DWORD dwBytesRead)
{
    if(!m_bOpened||m_hCommDev==NULL) return 0;
BOOL bReadStat;
DWORD dwErrorFlags;
COMSTAT ComStat; ClearCommError(m_hCommDev,&dwErrorFlags,&ComStat);
if(!ComStat.cbInQue) return 0;
dwBytesRead=min(dwBytesRead,(DWORD)ComStat.cbInQue);
bReadStat=ReadFile(m_hCommDev,buffer,dwBytesRead,&dwBytesRead,&m_OverlappedRead);
if(!bReadStat)
{
if(GetLastError()==ERROR_IO_PENDING)
{
WaitForSingleObject(m_OverlappedRead.hEvent,2000);
return dwBytesRead;
}
return 0;
}
return dwBytesRead;
}
DWORD TSerial::SendData(const char *buffer,DWORD dwBytesWritten)
{
   if(!m_bOpened||m_hCommDev==NULL)
   return 0;
   BOOL bWriteStat;
   bWriteStat=WriteFile(m_hCommDev,buffer,dwBytesWritten,&dwBytesWritten,&m_OverlappedWrite);
   if(!bWriteStat)
   {
   if(GetLastError()==ERROR_IO_PENDING)
   {
                WaitForSingleObject(m_OverlappedWrite.hEvent,1000);
                return dwBytesWritten;
   }
    return 0;
   }
  return dwBytesWritten;}
int TSerial::InBufferCount()
{
if(!m_bOpened||m_hCommDev==NULL)
return 0;
DWORD dwErrorFlags;
COMSTAT ComStat;
ClearCommError(m_hCommDev,&dwErrorFlags,&ComStat);
return (int)ComStat.cbInQue;
}
 /*
    char buffer[1000]={""};               //一定要让他初始化！！！！！
    UpdateData(true);
for(int i=0;i<m_Send.GetLength();i++)
buffer[i]=m_Send[i];
if(MyCom.Open(1,9600))
MyCom.SendData(buffer,m_Send.GetLength());
if(MyCom2.Open(2,9600))
{
MyCom2.ReadData(buffer,m_Send.GetLength());
m_Rec=CString(buffer);
UpdateData(false);
}   */void TSerial::Conv17_26(char T[17],int Number,char Result[26])
{
                        //T[17]是头子，既是data[] 以前的数据，
                        //Number 是填写的数据，对于D0003 就是通道数，对于D0001就是采集数，
                        //对于M0000，则是置1还是复0                        //Result 是最后结果。
   int p=0;
   char D[3]={""};
   char data[4]={""};
/*   if(Number<10)
   {
    data[0]='\x30';
    data[1]='\x30'+Number;
   }
   else
   {
     if(Number<16)
     {
       data[0]='\x30';
       data[1]='\x40'+Number-9;
     }
     else
     {
      data[0]='\x31';
      data[1]='\x30'+Number-16;
     }
   }
*/
   if(Number<10)
   {
    data[0]='\x30';
    data[1]='\x30'+Number;
   }
   else
   {
     if(Number<16)
     {
       data[0]='\x30';
       data[1]='\x40'+Number-9;
     }
     else if(Number<26)
     {
      data[0]='\x31';
      data[1]='\x30'+Number-16;
     }
     else if(Number<32)
     {
      data[0]='\x31';
      data[1]='\x40'+Number-25;
     }
     else if(Number<42)
     {
       data[0]='\x32';
       data[1]='\x30'+Number-32;
     }
     else if(Number<48)
     {
       data[0]='\x32';
       data[1]='\x40'+Number-41;
     }
     else if(Number<58)
     {
       data[0]='\x33';
       data[1]='\x30'+Number-48;
     }
     else if(Number<64)
     {
       data[0]='\x33';
       data[1]='\x40'+Number-57;
     }
     else if(Number<74)
     {
       data[0]='\x34';
       data[1]='\x30'+Number-64;
     }
     else if(Number<80)
     {
       data[0]='\x34';
       data[1]='\x40'+Number-73;
     }
     else if(Number<90)
     {
       data[0]='\x35';
       data[1]='\x30'+Number-80;
     }
     else //if(Number<96)
     {
       data[0]='\x35';
       data[1]='\x40'+Number-89;
     }
   }
   Result[0]=T[0];
   for(int i=1;i<17;i++)
   {
    Result[i]=T[i];
    p+=T[i];
   }   p+=data[0];
   p+=data[1];
   sprintf(D,"%x",p);
   p=CharToInt(D[1]);
   p>9?data[2]=('\x40'+p-9):data[2]=('\x30'+p);   p=CharToInt(D[2]);
   p>9?data[3]=('\x40'+p-9):data[3]=('\x30'+p);   for(i=0;i<4;i++)
   {
     Result[17+i]=data[i];
   }
   Result[21]='\x06';
   Result[22]='\x30';
   Result[23]='\x30';
   Result[24]='\x46';
   Result[25]='\x46';
}
int TSerial::CharToInt(char p)
{
    if(p<='9'&&p>='0') 
return (int)(p-'0');
else if(p>='A'&&p<='F') 
return (int)(10+p-'A');
    else 
return (int)(10+p-'a'); 
}希望对你有用！

Answer 2

See the link below, several samples there , useful :http://www.codeproject.com/system/#Hardware programming