Ubuntu Manpage: nmea - Process NMEA data

NAME

       nmea - Process NMEA data

SYNOPSIS

       package require Tcl 8.5 9

       package require nmea ?1.1.0?

       ::nmea::input sentence

       ::nmea::open_port port ?speed?

       ::nmea::close_port

       ::nmea::configure_port settings

       ::nmea::open_file file ?rate?

       ::nmea::close_file

       ::nmea::do_line

       ::nmea::rate

       ::nmea::log ?file?

       ::nmea::checksum data

       ::nmea::write sentence data

       ::nmea::event setence ?command?

________________________________________________________________________________________________________________

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 dispatched to user defined handler
       commands for processing.  To define a handler, see the event command. There are no GPS specific functions
       in this package. NMEA data consists of a sentence type, followed by a list of data.

COMMANDS

::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::input {$GPGSA,A,3,04,05,,09,12,,,24,,,,,2.5,1.3,2.1*39}
nmea::input [list GPGSA A 3 04 05 09 12 "" "" 24 "" "" "" 2.5 1.3 2.1]

::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::close_port
Close the com port connection if one is open.

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

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

::nmea::close_file
Close the open file if one exists.

::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::rate
Sets the rate at which lines are processed from the open file, in milliseconds. The rate remains
consistant across files, there does not need to be a file currently open to use this command. Set
to 0 to disable automatic line processing.

::nmea::log ?file?
Starts or stops input logging. If a file name is specified then all NMEA data recieved on the open
port will be logged to the ?file? in append mode. If file is an empty string then any logging will
be stopped. If no file is specified then returns a boolean value indicating if logging is
currently enabled. Data written to the port by write, data read from files, or input made using
input, is not logged.

::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 to the
port in proper NMEA checksummed format.

::nmea::event setence ?command?
Registers a handler proc for a given NMEA sentence. There may be at most one handler per sentence,
any existing handler is replaced. If no command is specified, returns the name of the current
handler for the given setence or an empty string if none exists. In addition to the incoming
sentences there are 2 builtin types, EOF and DEFAULT. The handler for the DEFAULT setence is
invoked if there is not a specific handler for that sentence. The EOF handler is invoked when End
Of File is reached on the open file or port.

The handler procedures, with the exception of the builtin types,must take exactly one argument,
which is a list of the data values. The DEFAULT handler should have two arguments, the sentence
type and the data values. The EOF handler has no arguments.

nmea::event gpgsa parse_sat_detail
nmea::event default handle_unknown

proc parse_sat_detail {data} {
puts [lindex $data 1]
}

proc handle_unknown {name data} {
puts "unknown data type $name"
}

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 Trackers [http://core.tcl.tk/tcllib/reportlist].  Please
       also report any ideas for enhancements you may have for either package and/or documentation.

       When proposing code changes, please provide unified diffs, i.e the output of diff -u.

       Note further that attachments are strongly preferred over inlined patches. Attachments  can  be  made  by
       going  to the Edit form of the ticket immediately after its creation, and then using the left-most button
       in the secondary navigation bar.

KEYWORDS

       gps, nmea

COPYRIGHT

       Copyright (c) 2006-2009, Aaron Faupell <afaupell@users.sourceforge.net>

tcllib                                                1.1.0                                           nmea(3tcl)