ATR72 NAV LCD is the software application developed to display the NAV frequencies (active and stand-by freq., see the image above) of the NAV1 radio on the LCD module (see the section LCD).
The program uses a library for the access to the parallel port (otherwise it wouldn't be possible under 2000/XP) where, at the moment, the LCD module is connected.
The only requirement needed is a registered version of FSUIPC (http://www.schiratti.com/dowson) and, of course, a 8x2 characters HD44780 LCD module.
The program reads every 100 ms two FSUIPC offsets:
311Eh Nav1 stand-by freq. (size: 2 bytes)
0350h Nav1 active freq. (size: 2 bytes)
and then sends the frequencies to the display but only if they are changed to minimize the impact of the program on the system.
The program is still under development since it will manage also NAV2 frequencies (on a second 8x2 LCD display) and autopilot settings and messages (on a third 20x4 LCD display).
If interested, you can download the program from the Download section.