Avionics Bending - Schematic: VHF COMM Radio

Here is the first of 7 postings that will show how I implemented the I/O board for the VHF COMM head as part of my Lockheed L-1011 project. First, let me describe the schematic to you:

A few weeks ago I posted a design specification document that asked for a micro-controller that has USB support. This was a relatively easy decision because I right away picked a micro-controller made by ATMEL. To be exact, i picked the AT90USB1286. So what better way to avoid SMD's than using the teensy++ as a mezzanine board for my project. However, the chip is only available as a surface mount (SMD) and my shaky hands a are not steady enough to solder a board with SMDs together myself. However, for the first go-around of this hardware solution I wanted to avoid the cost of having the board assembled. However, I found the AT90USB mounted as part of the teensy++ as sold by PJRC.

Besides the mezzanine board, I also have connectors for the Digit Drum and Light Plate illumination that is controlled externally. The Mark-I version of the board does not have a WatchDog implemented ... I will add that for Mark-II.

This multi-function board will provide the following:

• On-Board Power Conditioning to 5V
• 32bit or 40bit Input only
  
• 8bit ADC or 8bit High Current Output
• Analog Reference Input (AREF)
  
• Two basic analog inputs (AIN1/AIN2)
  
• Two Instrument Light Connectors (DRUM1/DRUM2)
  
• One Light Plate Connector (LB)
  

The idea is that the board will be usable for all drum-style radio heads, the transponder and the weather radar head .... amongst others.

You can check out the schematic as an image above, or you can click on the link to see the schematic as a PDF file: Radio Head Schematic