domenica 19 dicembre 2010

Character LCD Comm 1 and 2 module

here is an unusual approach to the Comm 1 and 2 radios interfacing which gives a really nice and realistic result.
2 years ago I had a deal and I got 2 real VHF Comm modules out of a 767 manufactured by AVTECH which I disassembled to see how to modify them in order to work with OC cards.

The removal of stock electronic has been quite easy but during the removal of the original LCD panels I got the idea: why don't try to replicate a similar result?
So after a bit of research on the net i found at Crystalfontz a LCD which coulded fit in terms of dimensions to the stock housing and I bought them.
They are 2 lines x 8 characters LCD displays featuring white chars on dark background which is what the stock LCD looks like.
After assembling and cabling everything up I made a first test to see how everything was operating and this is the result:

So as a first test I was really enthusiast but then lot of programming woulded be required in SIOC to make the thing working.
Basically for each display there are 3 virtual pages.

  • First one is empty and is called either when there is a failure detected or the appropriate power bus is off so it doesn't allow any tune or frequency display.
  • Second one represent the ACTIVE frequency and display the appropriate tuned frequency with the -ACTIVE- displayed in the 1st line. When this virtual display is active in the 1st phisical display, the active flag offset is on as well while in the 2nd phisical display the active flag is obviously off.
  • Third one represent the STANDBY frequency and in this page the frequency is the same as the active virtual display but -ACTIVE- is nomore displayed and the active flags is switched to off and at the same time switched to on in the 2nd phisical display.
This is how the real unit also operates and gives that piece of realism on a module which is really used during flights, specially online as i implemented the IVAP offsets to work according to the comm frequency and state.