DCB

typedef struct {

char Id; /* internal device ID */

ushort Baudrate; /* operating speed */

char ByteSize; /* transmit/receive byte size */

char Parity; /* 0,1,2,3, or 4 */

char StopBits; /* number of stop bits */

ushort RlsTimeout; /* timeout for RLSD to be set */

ushort CtsTimeout; /* timeout for CTS to be set */

ushort DsrTimeout; /* timeout for DSR to be set */

ushort fBinary: 1; /* binary-mode flag */

ushort fRtsDisable: 1; /* disable RTS */

ushort fParity: 1; /* enable parity checking */

ushort fDummy: 5;

ushort fOutX: 1; /* enable output XON/XOFF */

ushort fInX: 1; /* enable input XON/XOFF */

ushort fPeChar: 1; /* enable parity-error replacement */

ushort fNull: 1; /* enable null stripping */

ushort fChEvt: 1; /* enable Rx character event */

ushort fDtrflow: 1; /* enable DTR flow control */

ushort fRtsflow: 1; /* enable RTS flow control */

ushort fDummy2: 1;

char XonChar; /* transmit/receive XON character */

char XoffChar; /* transmit/receive XOFF character */

ushort XonLim; /* transmit XON threshold */

ushort XoffLim; /* transmit XOFF threshold */

char PeChar; /* parity error replacement character */

char EofChar; /* end-of-input character */

char EvtChar; /* event-generating character */

ushort TxDelay; /* amount of time between characters */

} DCB;

The DCB structure contains the RS-232 configuration parameters for a communication device.

Members

Id

Specifies the device ID byte (COM1 = 0, COM2 = 1, and so on). This is also the value returned by the cOpen function, when successful.

Baudrate

Specifies the operating speed; any baud rate supported by the hardware.

ByteSize

Specifies the transmitting and receiving byte size; normally in the range 4 through 8.

Parity

Specifies the parity setting. The value can be one of the following values.

StopBits

Specifies the number of stop bits. The value can be one of the following values.

RlsTimeout

Specifies the amount of time, in milliseconds, to wait for receiving-line-signal detect (RLSD) to become high. RLSD flow control can be achieved by specifying infinite timeout (0xFFFF).

CtsTimeout

Specifies the amount of time, in milliseconds, to wait for clear-to-send signal (CTS) to become high. CTS flow control can be achieved by specifying infinite timeout (0xFFFF).

DsrTimeout

Specifies the amount of time, in milliseconds, to wait for data-set-ready (DSR) to become high. DSR flow control can be achieved by specifying infinite timeout (0xFFFF).

fBinary

Specifies the binary-mode flag (0 is ASCII mode, 1 is binary). In ASCII mode, the end-of-file character (EOFCHAR) is recognized and remembered as the end of received data.

fRtsDisable

Disables the receive-transmission signal (RTS) line for as long as this device is open, if set. Normally, RTS is enabled when the device is opened and disabled when closed.

fParity

Enables parity checking, if set.

fOutX

Indicates that XON/XOFF flow control is to be used during transmission, if set. The transmitter halts when it receives an XOFF character, and starts again when it receives an XON character.

fInX

Indicates that XON/XOFF flow control is to be used during reception, if set.

fPeChar

Indicates that characters received with parity errors are to be replaced with the specified parity-checking characters (PECHAR), if set.

fNull

Specifies that the received null characters are to be discarded, if set.

fChEvt

Indicates that the reception of event-checking characters (EVTCHAR) are to be flagged as an event, if set.

fDtrFlow

Indicates that the data-terminal-ready signal (DTR) is to be used for receive flow control, if set.

fRtsflow

Indicates that the receive-transmission signal (RTS) is to be used for receive flow control, if set.

XonChar

Specifies the XON character for both transmit and receive.

XoffChar

Specifies the XOFF character for both transmit and receive.

XonLim

Specifies the threshold value for receive queue. When the receive queue comes within 10 characters of being full, it transmits an XOFF character. When the queue comes within 10 characters of being empty, an XON character will be transmitted.

XoffLim

Specifies the threshold value for send queue. When the number of characters in the receive queue exceeds this value, an XOFF character is sent (if XOFF flow control is enabled) and the data-terminal-ready signal (DTR) is dropped (if enabled).

PeChar

Specifies the character to be used as replacement when a parity error occurs.

EofChar

Specifies the character that signals the end of the input.

EvtChar

Specifies the character that triggers an event flag.

TxDelay

Specifies the minimum amount of time that must pass between transmission of characters.

See Also

getdcb, inicom, setcom