程序分为两个部分。 /* MySerialPort.h
封装了串口通讯的windows API。 支持异步操作串口。 */
#pragma once
#include
namespace jeff_class {
class CMySerialPort {
public:
CMySerialPort(); ~CMySerialPort();
BOOL Open ( int nPort = 2, int nBaud = 9600 ); BOOL Close ( void );
int ReadData ( void *, int );
int SendData ( const char *, int );
int ReadDataWaiting ( void ); // 查询缓冲区内是否有未读取的数据
BOOL IsOpened ( void ) { return ( m_bOpened ); }
protected:
BOOL WriteCommByte ( unsigned char ); // 内部实现，向串口写数据
HANDLE m_hIDComDev;
OVERLAPPED m_OverlappedRead, m_OverlappedWrite; BOOL m_bOpened; }; }
/ ****MySerialPort.cpp***********/
#include \#include
// 不使用读超时
#define TIMEOUT_READ_INTERVAL 0xFFFFFFFF
#define TIMEOUT_READ_TOTAL_MULTIPLIER 0 #define TIMEOUT_READ_TOTAL_CONSTANT 0 // 写超时为秒
#define TIMEOUT_WRITE_TOTAL_MULTIPLIER 0 #define TIMEOUT_WRITE_TOTAL_CONSTANT 5000
// 推荐的输入/输出缓冲区（注意：实际值由系统设置） #define BUFFER_INPUT_RECOMMEND 10000 #define BUFFER_OUTPUT_RECOMMEND 10000
// 异步读取/写入操作时等待事件的超时时间 #define TIMEOUT_READCOMM_EVENT 4000 #define TIMEOUT_WRITECOMM_EVENT 2000
// 一些通讯协议使用的宏
#define FC_DTRDSR 0x01 #define FC_RTSCTS 0x02 #define FC_XONXOFF 0x04 #define ASCII_BEL 0x07 #define ASCII_BS 0x08 #define ASCII_LF 0x0A #define ASCII_CR 0x0D #define ASCII_XON 0x11 #define ASCII_XOFF 0x13
jeff_class::CMySerialPort::CMySerialPort() {
memset ( &m_OverlappedRead, 0, sizeof ( OVERLAPPED ) ); memset ( &m_OverlappedWrite, 0, sizeof ( OVERLAPPED ) ); m_hIDComDev = NULL; m_bOpened = FALSE; }
jeff_class::CMySerialPort::~CMySerialPort() {
Close(); }
// 打开串口
BOOL jeff_class::CMySerialPort::Open ( int nPort, int nBaud ) {
if ( m_bOpened ) return TRUE;
TCHAR szPort[50];
TCHAR szComParams[50]; DCB dcb;
wsprintf ( szPort, _T ( \ ), nPort );
// API：建立文件，Windows中将串口设备当做文件对待 m_hIDComDev = CreateFile ( szPort,
GENERIC_READ | GENERIC_WRITE, 0, NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, // 异步读写
NULL );
if ( m_hIDComDev == NULL ) return ( FALSE );
memset ( &m_OverlappedRead, 0, sizeof ( OVERLAPPED ) ); memset ( &m_OverlappedWrite, 0, sizeof ( OVERLAPPED ) );
// 设置超时
COMMTIMEOUTS CommTimeOuts;
CommTimeOuts.ReadIntervalTimeout = TIMEOUT_READ_INTERVAL;
CommTimeOuts.ReadTotalTimeoutMultiplier = TIMEOUT_READ_TOTAL_MULTIPLIER; CommTimeOuts.ReadTotalTimeoutConstant = TIMEOUT_READ_TOTAL_CONSTANT; CommTimeOuts.WriteTotalTimeoutMultiplier= TIMEOUT_WRITE_TOTAL_MULTIPLIER;
CommTimeOuts.WriteTotalTimeoutConstant = TIMEOUT_WRITE_TOTAL_CONSTANT;
SetCommTimeouts ( m_hIDComDev, &CommTimeOuts );
wsprintf ( szComParams, _T ( \ ), nPort, nBaud );
// 设置异步读取/写入监视事件
m_OverlappedRead.hEvent = CreateEvent ( NULL, TRUE, FALSE, NULL ); m_OverlappedWrite.hEvent = CreateEvent ( NULL, TRUE, FALSE, NULL );
// 读取/设置串口设备参数
dcb.DCBlength = sizeof ( DCB ); GetCommState ( m_hIDComDev, &dcb ); dcb.BaudRate = nBaud; 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, BUFFER_INPUT_RECOMMEND, BUFFER_OUTPUT_RECOMMEND ) ||
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 ); return ( FALSE ); }
m_bOpened = TRUE;
return ( m_bOpened ); }
// 关闭串口
BOOL jeff_class::CMySerialPort::Close ( void ) {
if ( !m_bOpened || m_hIDComDev == NULL ) return ( TRUE );
if ( m_OverlappedRead.hEvent != NULL ) CloseHandle ( m_OverlappedRead.hEvent );
if ( m_OverlappedWrite.hEvent != NULL ) CloseHandle ( m_OverlappedWrite.hEvent );
CloseHandle ( m_hIDComDev ); m_bOpened = FALSE; m_hIDComDev = NULL;
return ( TRUE ); }