Altitude Encoder Serial-to-Parallel Converter

for the Dynon Avionics EFIS-D10A

Altitude Encoder PCB
as of: 23 Sep 2004

Schematic (382 kB)

This is a JPEG image of the schematic of the Encoder Converter so you can determine the complexity of the project without downloading anything further.  Note that the 7806 regulator (U6) and capacitor C14 are not needed here; I use this same PCB (with different firmware) for another project -- an RC model airplane servo controller used for electric trim in my Long-EZ.

Schematic and PCB Layout Diagrams
(67 kB)

This ZIP file contains everything needed to send to ExpressPCB to produce a circuit board.  Note that there are no Gerber files; ExpressPCB uses a proprietary format.  You will need to download ExpressPCB's free
schematic and PCB design software in order to view these files.  Using that software you can view and modify the schematic diagram and all of the PCB layers (top, bottom, and silkscreen).

Firmware version 1.02 (.HEX) file (15 kB)

This is the actual firmware for the Encoder Converter microprocessor's flash memory.  Select your browser's "Save it to disk" option when downloading it.  You will need a device capable of programming an Atmel ATmega8 microprocessor (I use the Atmel STK-500 which is available from DigiKey).

Installation documentation (1.5 MB)

This is the documentation for installation and verification of the Encoder Converter.   It is not intended for construction but a schematic diagram of the unit itself  is included in the appendix. 

Schematic diagram of an Altitude Encoder Tester (240 kB)

This is a device you can build to display and check the output of the Encoder Converter (or any parallel Gray code output altitude encoder such as the ACK A-30).  The input is parallel Gray code and the output is displayed on LEDs.

Mode C encoder data table (25 kB)

This is a table showing the states of the output lines of the Encoder Converter (or any parallel altitude encoder) vs. altitude.  It is used with the Altitude Encoder Tester (above) for verifying the output of an altitude encoder.

Application program to update Encoder Converter's flash memory (121 kB)

This program runs on a Windows PC and updates the Encoder Converter's firmware if/when necessary.  Its use is optional but if used, it requires that bootloader firmware be programmed into the ATmega8 microprocessor and the appropriate fuses set.   When I assemble the Encoder Converter, I program the bootloader into the microprocessor in my STK-500, connect the Encoder Converter to the PC, and flash its firmware with the Encoder Converter's firmware.  Contact me for the bootloader hex file and fuse settings.

Joe Dubner
jdubner at