nmea(n) 						   NMEA protocol implementation 						   nmea(n)

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NAME

       nmea - Process NMEA data

SYNOPSIS

       package require Tcl  8.2

       package require nmea  ?0.1.1?

       ::nmea::open_port port ?speed?

       ::nmea::open_file file rate

       ::nmea::input sentence

       ::nmea::configure_port settings

       ::nmea::close_port

       ::nmea::close_file

       ::nmea::do_line

       ::nmea::log file

       ::nmea::checksum data

       ::nmea::write sentence data

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DESCRIPTION

       This  package  provides	a standard interface for writing software which recieves NMEA standard input data. It allows for reading data from
       COM ports, files, or programmatic input. It also supports the checksumming and logging of incoming data.   After  parsing,  input  is  dis-
       patched	to  user  defined  handler  commands for processing.  To define a handler, create a proc with the NMEA sentence name in the ::nmea
       namespace. For example, to process GPS fix data use "proc ::nmea::GPGSA". The proc must take one argument, which is a list of the data val-
       ues.

COMMANDS

       ::nmea::open_port port ?speed?
	      Open the specified COM port and read NMEA sentences when available. Port speed is set to 4800bps by default or to speed.

       ::nmea::open_file file rate
	      Open  file  file and read NMEA sentences, one per line, at the rate by rate in milliseconds.  The file format may omit the leading $
	      and/or the checksum. If rate is <= 0 then lines will only be processed when a call to do_line is made. The rate may be  adjusted	by
	      setting ::nmea::nmea(rate).

       ::nmea::input sentence
	      Processes  and  dispatches  the  supplied sentence. If sentence contains no commas it is treated as a Tcl list, otherwise it must be
	      standard comma delimited NMEA data, with an optional checksum and leading $.

       ::nmea::configure_port settings
	      Changes the current port settings. settings has the same format as fconfigure -mode.

       ::nmea::close_port
	      Close the open port

       ::nmea::close_file
	      Close the open file

       ::nmea::do_line
	      If there is a currently open file, this command will read and process a single line from it. Returns the number of lines read.

       ::nmea::log file
	      Starts or stops file logging. If a file name is specified then all NMEA output will be logged to the file in append mode. If file is
	      an empty string then any logging will be stopped.

       ::nmea::checksum data
	      Returns the checksum of the supplied data

       ::nmea::write sentence data
	      If there is a currently open port, this command will write the specified sentence and data in proper NMEA checksummed format.

VARIABLES

       ::nmea::checksum
	      A boolean value which determines whether incoming sentences are validated or not.

       ::nmea::rate
	      When reading from a file this sets the rate that lines are processed in milliseconds.

BUGS, IDEAS, FEEDBACK
       This  document, and the package it describes, will undoubtedly contain bugs and other problems.	Please report such in the category nmea of
       the Tcllib SF Trackers [http://sourceforge.net/tracker/?group_id=12883].  Please also report any ideas for enhancements you  may  have  for
       either package and/or documentation.

KEYWORDS

       gps, nmea

COPYRIGHT

       Copyright (c) 2006-2007, Aaron Faupell <afaupell@users.sourceforge.net>

nmea									0.1								   nmea(n)