TDCGPS.OPA - NMEA reader for Psion 3a
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Place the .OPA file in your \APP directory, and use Psion-I to add to the main menu.

All other files (i.e. any .PIC files, .DBF etc), should go into the \APP\TDCGPS directory.  You will need to create this if it does not exist already.

It works with the Rockwell MicroTracker LP, but is OK with a number of other systems.

Simon Taylor
100043.104@compuserve.com

Revision history :
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b0.04  21/03/96
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* Tidied up menu.

* Map is now selected to foreground when which map function used, and map is in background.

* Speed alarm made settable, and has variable tone alarm, getting higher pitched as speed increases.

* Added map preview option.

* Bug in Track display as position crosses minute borders fixed, previously would 'jump' across display.

* Dramatically improved handing of serial errors.

* Track display buffer optimised, improvement in main program loop speed.

* Map pointer sprite made more visible.

* Remote link if switched on is automatically switched off.

* Speed & heading numeric values made non-proportional to avoid display corruption.

* Knots speed display changed to integer.

* Map brought to foreground upon exit to preserve ordered display of windows upon re-start.

b0.03  14/03/96
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* Added mapping facility.

* Added Track display, 100 values are stored at a programmed interval (default 10 seconds, range is 5 to 60 seconds).  Display auto-scales, and shows current position and track of route taken.

* Fixed bug in NGR sheet prefix letters calculation.

* Added space to odometer display when in miles, previously showed feet symbol from the prior display.

* Added space after altitude display.

* Odometer reset command now works.

Known problems :

Serial overrun occurs after execution of program for some time, corrupts lat/long display.

If GPS is disconnected, Psion-X will not exit program, you must use Psion-ESC.

If map is in foreground when program is exited, order of windows is corrupted upon re-running program.

A new revision is planned by the end of March, and will be available on Compuserve, and the TDC BBS (01256 57900).

b0.02  30/01/96
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* Added two spaces after the DGPS timeout value to avoid old displays being added to single-digit timeout numbers.

b0.01  29/01/96
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* Added configurable DGPS port, moveable windows and UK NGR calculation.

* TDCGPS.WRD is the beginnings of the new 'manual' for the program.

* Also added compatibility with other GPSs thanks to sample data from David Trussell.

b0.00  23/01/96
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* Interim version with system screen and new icon.

V0.00  15/01/96
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* First release, requires addition of system screen and full implementation of place database, movable windows.  Only one menu command is properly implemented - Exit (!).
