ARINC 410 Interface subsystem, Continued

More information and gotchas:  

Interface Specification:  Remember I said that that the ARINC-410 has 5 bits?  That means our Bus_0 through Bus_4 is the ARINC-410 A throgh E.  Now I can use Bus_5 for Read/Write (the write is Low Active). Ok that only leaves one more,  Bus_6 and I’m going to use it for a strobe. I can do that with a Schmitt Trigger.  Now I did say that was all, but hey what about a reset line?? I don’t know if I need one but we can use Bus_7, and that gives us all 8 bits in the interface.

Outputs:  Well what are our outputs?  The table below shows the standard outputs, that is what the interface has to drive.

Function	Voltage	Notes
Panel Lights	28v
Dial Lights	28v
DME Lamp	28v	Only on NAV

We read the position of the power switch in the status register. But it would be nice to drive all those fault flags.  So how do you drive 28vdc from TTL? There are really 4 ways:

1. High Voltage Inverter Buffer/Drivers; such as 5406, 5416, 7406, 7416. But have no voltage immunity.
2. Relays; You still need to drive them, that is the coil.
3. Optoisolator;  such as TIL111. My personal choice for driving HV loads, and there good for 70volts..
4. Solid State Relays; SSR’s are robust, and can handle both large currents and high voltages.. You can find used ones on ebay.

Audio:  The Gables Radio’s have Volume IN-HI, IN-LOW, OUT-HI and OUT-LOW. This will be a headache  that I don’t want to deal with in this post. But we still need to handle the audio some how. This leaves two choices:

1. Do what Microsoft Flight Simulator and others do. Just ignore it.
2. Lets build an audio sub-system.  The benefits really starts to shine when you have more that one position to fill.. ie. pilot, co-pilot, navigator, weapons officer
   • If you fly VATSIM their audio is now on a channel, on the COMM head.
   • We now can simulate Morse Code signals & DME milage station on the NAV head. More later as this will dictate other changes, like outputs to drive from-to flags, etc.
   • You can chain the audio outputs.
   • You can have the same audio at the instructors console.
   • You can record the audio for play back.

Looks like we need a part 3 later..