营销串行设备驱动.ppt

读串口 BYTE Byte; DWORD dwBytesTransferred; ReadFile (hPort, // Port handle Byte, // Pointer to data to read 1, // Number of bytes to read dwBytesTransferred, // Pointer to number of bytes // read NULL // Must be NULL for Windows CE ); * 使用通讯事件 BYTE Byte; DWORD dwBytesTransferred; // Specify a set of events to be monitored for the port. SetCommMask (hPort, EV_RXCHAR | EV_CTS | EV_DSR | EV_RLSD | EV_RING); while (hPort != INVALID_HANDLE_VALUE) { // Wait for an event to occur for the port. WaitCommEvent (hPort, dwCommModemStatus, 0); // Re-specify the set of events to be monitored for the port. SetCommMask (hPort, EV_RXCHAR | EV_CTS | EV_DSR | EV_RING); if (dwCommModemStatus EV_RXCHAR) { // Loop for waiting for the data. do { // Read the data from the serial port. ReadFile (hPort, Byte, 1, dwBytesTransferred, 0); // Display the data read. if (dwBytesTransferred == 1) ProcessChar (Byte); } while (dwBytesTransferred == 1); } * 通讯事件简介 Event Description EV_BREAK A break occurred on input. EV_CTS The CTS signal changed state. EV_DSR The DSR signal changed state. EV_ERR A line-status error occurred. Line-status errors are CE_FRAME, CE_OVERRUN, and CE_RXPARITY. EV_RING A ring indicator was detected. EV_RLSDThe receive-line-signal-detect signal changed state. EV_RXCHAR A character was received and placed in the input buffer. EV_RXFLAG The event character was received and placed in the input buffer. EV_TXEMPTY The last character in the output buffer was sent. * 关闭串口 BOOL CloseHandle( HANDLE hObject ); 关闭一个已经打开的对象句柄，使用这种方法来关闭串口 参数：待关闭的句柄 返回值：是否关闭成功 * 5、红外设备简介 * . 红外通讯 红外线是波长在750nm至1mm之间的电磁波，其频率高于微波而低于可见光，是一种人的眼眼看不到的光线。 目前无线电波和微波已被广泛应用在长距离的无线通信中，但由于红外线的波长较短，对障碍物的衍射能力差，所以更适合应用在需要短距离无线通信场合点对点的直接线数据传输。 * 红外协议栈 * 各模块解释 物理层协议（Physical Layer） 制定了红外通信硬件设计上的目标和要求，包括红外的光特性、