nmea - Process NMEA data

       This document, and the package it describes, will undoubtedly contain bugs and  other  problems.   Please
       report  such  in the category nmea of the TcllibTrackers [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 unifieddiffs, 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.

       Networking

::nmea::inputsentence
              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_portport ?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_portsettings
              Changes the current port settings. settings has the same format as fconfigure -mode.

       ::nmea::open_filefile ?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::checksumdata
              Returns the checksum of the supplied data.

       ::nmea::writesentencedata
              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::eventsetence ?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"
              }

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

tcllib                                                1.1.0                                           nmea(3tcl)

       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.

       gps, nmea

       nmea - Process NMEA data

       package require Tcl8.59

       package require nmea?1.1.0?::nmea::inputsentence::nmea::open_portport ?speed?

       ::nmea::close_port::nmea::configure_portsettings::nmea::open_filefile ?rate?

       ::nmea::close_file::nmea::do_line::nmea::rate::nmea::log ?file?

       ::nmea::checksumdata::nmea::writesentencedata::nmea::eventsetence ?command?

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