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串口通讯中的DCB结构
typedef struct _DCB {// dcb DWORD DCBlength; // sizeof(DCB) DORD BaudRate; // current baud rate 指定当前的波特率 DWORD fBinary: 1; // binary mode, no EOF check 指定是否允许二进制模式WIN95中须为TRUE DWORD fParity: 1; // enable parity checking 指定奇偶校验是否允许 DWORD fOutxCtsFlow:1; // CTS output flow control 指定CTS是否用于检测发送控制。当为TRUE时CTS为 // OFF，发送将被挂起。（发送清楚） DWORD fOutxDsrFlow:1; // DSR output flow control 指定CTS是否用于检测发送控制。 //（数据装备好） 当为TRUE是CTS为OFF，发送将被挂起。 DWORD fDtrControl:2; // DTR flow control type //DTR_CONTROL_DISABLE值将DTR置为OFF, //DTR_CONTROL_ENABLE值将DTR置为ON, DTR_CONTROL_HANDSHAKE 允许DTR"握手", DWORD fDsrSensitivity:1; // DSR sensitivity 当该值为TRUE时DSR为OFF时接收的字节被忽略 DWORD fTXContinueOnXoff:1; // XOFF continues Tx 指定当接收缓冲区已满,并且驱动程序已经发送出XoffChar字符时发送是否停止。 TRUE时，在接收缓冲区接收到缓冲区已满的字节XoffLim且驱动程序已经发送出XoffChar字 符中止接收字节之后，发送继续进行。 FALSE时，在接收缓冲区接收到代表缓冲区已空的字节XonChar且驱动程序已经发送出恢复 发送的XonChar之后，发送继续进行。 DWORD fOutX: 1; // XON/XOFF out flow control TRUE时，接收到XoffChar之后便停止发送 接收到XonChar之后将重新开始 DWORD fInX: 1; // XON/XOFF in flow control TRUE时，接收缓冲区接收到代表缓冲区满的XoffLim之后，XoffChar发送出去 接收缓冲区接收到代表缓冲区空的XonLim之后，XonChar发送出去 DWORD fErrorChar: 1; // enable error replacement 该值为TRUE且fParity为TRUE时，用ErrorChar 成员指定的字符代替奇偶校验错误的接收字符 DWORD fNull: 1; // enable null stripping TRUE时，接收时去掉空（0值）字节 DWORD fRtsControl:2; // RTS flow control DWORD fAbortOnError:1; // abort reads/writes on error TRUE时,有错误发生时中止读和写操作 RTS_CONTROL_DISABLE时,RTS置为OFF RTS_CONTROL_ENABLE时, RTS置为ON RTS_CONTROL_HANDSHAKE时, 当接收缓冲区小于半满时RTS为ON 当接收缓冲区超过四分之三满时RTS为OFF RTS_CONTROL_TOGGLE时, 当接收缓冲区仍有剩余字节时RTS为ON ,否则缺省为OFF DWORD fDummy2:17; // reserved 未使用 WORD wReserved; // not currently used 未使用,必须为0 WORD XonLim; // transmit XON threshold 指定在XON字符发送这前接收缓冲区中可允许的最小字节数 WORD XoffLim; // transmit XOFF threshold 指定在XOFF字符发送这前接收缓冲区中可允许的最小字节数 BYTE ByteSize; // number of bits/byte, 4-8 指定端口当前使用的数据位 BYTE Parity; // 0-4=no,odd,even,mark,space 指定端口当前使用的奇偶校验方法,可能为: EVENPARITY,MARKPARITY,NOPARITY,ODDPARITY BYTE StopBits; 0,1,2 = 1, 1.5, 2 指定端口当前使用的停止位数,可能为: ON char XonChar; // Tx and Rx XON character 指定用于发送和接收字符XON的值 char XoffChar; // Tx and Rx XOFF character 指定用于发送和接收字符XOFF值 char ErrorChar; // error replacement character本字符用来代替接收到的奇偶校验发生错误时的值 char EofChar; // end of input character 当没有使用二进制模式时,本字符可用来指示数据的结束 char EvtChar; // received event character 当接收到此字符时,会产生一个事件 WORD wReserved1; // reserved; do not use 未使用 } DCB; -------------------------------------- DCB The DCB structure defines the control setting for a serial communications device. typedef struct _DCB { // dcb DWORD DCBlength; // sizeof(DCB) DWORD BaudRate; // current baud rate DWORD fBinary: 1; // binary mode, no EOF check DWORD fParity: 1; // enable parity checking DWORD fOutxCtsFlow:1; // CTS output flow control DWORD fOutxDsrFlow:1; // DSR output flow control DWORD fDtrControl:2; // DTR flow control type DWORD fDsrSensitivity:1; // DSR sensitivity DWORD fTXContinueOnXoff:1; // XOFF continues Tx DWORD fOutX: 1; // XON/XOFF out flow control DWORD fInX: 1; // XON/XOFF in flow control DWORD fErrorChar: 1; // enable error replacement DWORD fNull: 1; // enable null stripping DWORD fRtsControl:2; // RTS flow control DWORD fAbortOnError:1; // abort reads/writes on error DWORD fDummy2:17; // reserved WORD wReserved; // not currently used WORD XonLim; // transmit XON threshold WORD XoffLim; // transmit XOFF threshold BYTE ByteSize; // number of bits/byte, 4-8 BYTE Parity; // 0-4=no,odd,even,mark,space BYTE StopBits; // 0,1,2 = 1, 1.5, 2 char XonChar; // Tx and Rx XON character char XoffChar; // Tx and Rx XOFF character char ErrorChar; // error replacement character char EofChar; // end of input character char EvtChar; // received event character WORD wReserved1; // reserved; do not use } DCB; Members DCBlength Specifies the length, in bytes, of the DCB structure. BaudRate Specifies the baud rate at which the communications device operates. This member can be an actual baud rate value, or on CBR_300 CBR_38400 CBR_600 CBR_56000 CBR_1200 CBR_57600 CBR_2400 CBR_115200 CBR_4800 CBR_128000 CBR_9600 CBR_256000 CBR_14400 fBinary Specifies whether binary mode is enabled. The Win32 API does not support nonbinary mode transfers, so this member must be TRUE. Using FALSE will not work. fParity Specifies whether parity checking is enabled. If this member is TRUE, parity checking is performed and errors are reported. fOutxCtsFlow Specifies whether the CTS (clear-to-send) signal is monitored for output flow control. If this member is TRUE and CTS is turned off, output is suspended until CTS is sent again. fOutxDsrFlow Specifies whether the DSR (da fDtrControl Specifies the DTR (da DTR_CONTROL_DISABLE Disables the DTR line when the device is opened and leaves it disabled. DTR_CONTROL_ENABLE Enables the DTR line when the device is opened and leaves it on. DTR_CONTROL_HANDSHAKE Enables DTR handshaking. If handshaking is enabled, it is an error for the application to adjust the line by using the EscapeCommFunction function. fDsrSensitivity Specifies whether the communications driver is sensitive to the state of the DSR signal. If this member is TRUE, the driver ignores any bytes received, unless the DSR modem input line is high. fTXContinueOnXoff Specifies whether transmission stops when the input buffer is full and the driver has transmitted the XoffChar character. If this member is TRUE, transmission continues after the input buffer has come within XoffLim bytes of being full and the driver has transmitted the XoffChar character to stop receiving bytes. If this member is FALSE, transmission does not continue until the input buffer is within XonLim bytes of being empty and the driver has transmitted the XonChar character to resume reception. fOutX Specifies whether XON/XOFF flow control is used during transmission. If this member is TRUE, transmission stops when the XoffChar character is received and starts again when the XonChar character is received. fInX Specifies whether XON/XOFF flow control is used during reception. If this member is TRUE, the XoffChar character is sent when the input buffer comes within XoffLim bytes of being full, and the XonChar character is sent when the input buffer comes within XonLim bytes of being empty. fErrorChar Specifies whether bytes received with parity errors are replaced with the character specified by the ErrorChar member. If this member is TRUE and the fParity member is TRUE, replacement occurs. fNull Specifies whether null bytes are discarded. If this member is TRUE, null bytes are discarded when received. fRtsControl Specifies the RTS (request-to-send) flow control. If this value is zero, the default is RTS_CONTROL_HANDSHAKE. This member can be on RTS_CONTROL_DISABLE Disables the RTS line when the device is opened and leaves it disabled. RTS_CONTROL_ENABLE Enables the RTS line when the device is opened and leaves it on. RTS_CONTROL_HANDSHAKE Enables RTS handshaking. The driver raises the RTS line when the "type-ahead" (input) buffer is less than on RTS_CONTROL_TOGGLE Specifies that the RTS line will be high if bytes are available for transmission. After all buffered bytes have been sent, the RTS line will be low. fAbortOnError Specifies whether read and write operations are terminated if an error occurs. If this member is TRUE, the driver terminates all read and write operations with an error status if an error occurs. The driver will not accept any further communications operations until the application has acknowledged the error by calling the ClearCommError function. fDummy2 Reserved; do not use. wReserved Not used; must be set to zero. XonLim Specifies the minimum number of bytes allowed in the input buffer before the XON character is sent. XoffLim Specifies the maximum number of bytes allowed in the input buffer before the XOFF character is sent. The maximum number of bytes allowed is calculated by subtracting this value from the size, in bytes, of the input buffer. ByteSize Specifies the number of bits in the bytes transmitted and received. Parity Specifies the parity scheme to be used. This member can be on EVENPARITY Even MARKPARITY Mark NOPARITY No parity ODDPARITY Odd SPACEPARITY Space StopBits Specifies the number of stop bits to be used. This member can be on ON ON TWOSTOPBITS 2 stop bits XonChar Specifies the value of the XON character for both transmission and reception. XoffChar Specifies the value of the XOFF character for both transmission and reception. ErrorChar Specifies the value of the character used to replace bytes received with a parity error. EofChar Specifies the value of the character used to signal the end of da EvtChar Specifies the value of the character used to signal an event. wReserved1 Reserved; do not use. Remarks When a DCB structure is used to configure the 8250, the following restrictions apply to the values specified for the ByteSize and StopBits members: The number of da The use of 5 da QuickInfo Windows NT: Requires version 3.1 or later. Windows: Requires Windows 95 or later. Windows CE: Requires version 1.0 or later. Header: Declared in winbase.h. See Also Communications Overview, Communication Structures, BuildCommDCB, ClearCommError, EscapeCommFunction, GetCommState, SetCommState  转发至微博 转发至微博 |
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