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4/8/2010

The GPS Intermediate Driver uses the registry to determine how to connect to physical GPS hardware.

The GPS Intermediate Driver uses the settings in this topic when the InterfaceTyperegistry entry is "COMM". For more information about the InterfaceTyperegistry entry, see GPS Intermediate Driver Input Source Registry Settings.

Like the InterfaceTyperegistry entry, these entries exist in a key named for the specific input source, beneath the HKEY_LOCAL_MACHINE\System\CurrentControlSet\GPS Intermediate Driver\Driverskey. For example, an input source that uses GPS hardware accessible at a specific COM port might have registry settings at the HKEY_LOCAL_MACHINE\System\CurrentControlSet\GPS Intermediate Driver\Drivers\AcmeGPSHardwarekey.

Note:
On some target devices, the root GPS Intermediate Driver registry key, and all subkeys, are protected. On these target devices, untrusted applications can read but cannot write GPS Intermediate Driver settings.

The following table shows the registry entry that specifies GPS hardware connection information.

Value : type Description

CommPort: REG_SZ

No default setting.

Name of the COM port to which the physical GPS hardware is connected. For example, "COM1:".

During initialization, the GPS Intermediate Driver calls the SetupCommfunction. The following table shows the registry entries from which the GPS Intermediate Driver retrieves parameters for the call to SetupComm.

Value : type Description

InputBufferSize: REG_SZ

Default setting is 4096 bytes.

Size, in bytes, of the physical GPS hardware's input buffer.

OutputBufferSize: REG_SZ

Default setting is 4096 bytes.

Size, in bytes, of the physical GPS hardware's output buffer.

During initialization, the GPS Intermediate Driver calls the SetCommStatefunction. The following table shows the registry entries from which the GPS Intermediate Driver retrieves parameters for the call to SetCommState. For additional information about these settings, see DCB.

Value : type Description

Baud: REG_DWORD

Default setting is 4800 baud.

Baud rate at which the GPS hardware operates.

ByteSize: REG_DWORD

Default setting is 8 bytes.

Number of bits in the bytes transmitted or received.

Parity: REG_DWORD

Default setting is 0 (NOPARITY, defined in DCB).

Parity scheme. Can be EVENPARITY, MARKPARITY, NOPARITY, ODDPARITY, or SPACEPARITY.

StopBits: REG_DWORD

Default setting is 0 (ONESTOPBIT, defined in DCB).

Number of stop bits. Can be ONESTOPBIT, ONE5STOPBITS, or TWOSTOPBITS.

fInX: REG_DWORD

Default setting is FALSE.

Whether XON/XOFF flow control is used during reception.

fOutX: REG_DWORD

Default setting is FALSE.

Whether XON/XOFF flow control is used during transmission.

fOutxDsrFlow: REG_DWORD

Default setting is FALSE.

Whether the DSR (data-set-ready) signal is monitored for output flow control.

If this value is TRUE and DSR is turned off, output is suspended until DSR is sent again.

fOutxCtsFlow: REG_DWORD

Default setting is FALSE.

Whether the CTS (clear-to-send) signal is monitored for output flow control.

If this value is TRUE and CTS is turned off, output is suspended until CTS is sent again.

fDtrControl: REG_DWORD

Default setting is 0x01 (DTR_CONTROL_ENABLE, defined in DCB).

DTR (data-terminal-ready) flow control. Can be DTR_CONTROL_DISABLE, DTR_CONTROL_ENABLE, or DTR_CONTROL_HANDSHAKE.

fRtsControl: REG_DWORD

Default setting is 0x01 (DTR_CONTROL_ENABLE, defined in DCB).

RTS (request-to-send) flow control. Can be RTS_CONTROL_DISABLE, RTS_CONTROL_ENABLE, RTS_CONTROL_HANDSHAKE, or RTS_CONTROL_TOGGLE.

fBinary: REG_DWORD

Default setting is TRUE.

Whether binary mode is enabled. This value must be TRUE.

fParity: REG_DWORD

Default setting is FALSE.

Whether parity checking is enabled. If TRUE, parity checking is performed and errors are reported.

During initialization, the GPS Intermediate Driver calls the SetCommTimeoutsfunction. The following table shows the registry entries from which the GPS Intermediate Driver retrieves parameters for the call to SetCommTimeouts. For additional information about these settings, see COMMTIMEOUTS.

Value : type Description

ReadIntervalTimeout: REG_DWORD

Default setting is 50 milliseconds.

Maximum acceptable time, in milliseconds, that can elapse between the arrival of two bytes.

If this period of time is exceeded, the ReadFileoperation is completed and buffered data is returned.

ReadTotalTimeoutMultiplier: REG_DWORD

Default setting is 0 milliseconds.

Multiplier, in milliseconds, used to calculate the total timeout period for read operations.

For each read operation, this value is multiplied by the requested number of bytes to be read.

ReadTotalTimeoutConstant: REG_DWORD

Default setting is 500 milliseconds.

Constant, in milliseconds, used to calculate the total timeout period for read operations.

For each read operation, this value is added to the product of the ReadTotalTimeoutMultiplierentry and the requested number of bytes.

WriteTotalTimeoutMultiplier: REG_DWORD

Default setting is 0 milliseconds.

Multiplier, in milliseconds, used to calculate the total timeout period for write operations.

For each write operation, this value is multiplied by the number of bytes to be written.

WriteTotalTimeoutConstant: REG_DWORD

Default setting is 1000 milliseconds.

For each write operation, this value is added to the product of the WriteTotalTimeoutMultiplierentry and the number of bytes to be written.

See Also