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OTRSP to BCD Converter
on ATMEL ATmega8 microcontroller
Old Antenna selectors with BCD input cannot be used with new computers, that don't have LPT ports.
OTRSP to BCD converter can be usefull in this case. Converter must be connected between computer (USB port) and
Antenna Selector (BCD input). Antenna number from logging software (e.g. Logger32) is sent to Conveter in
Open Two Radio Switching Protocol (OTRSP).
Hardware part of project was made using free KiCad software, program for ATMega8 chip was written using Bascom AVR software.
All source files are included.
Antenna selector uses:
Schema of the OTRSP to BCD Converter is as follow:
I made a project in Kicad software, but I didn't make PCB board and I didn't test it. I have only 3D views of the board:
Program was tested in ATMega8 prototype board and works fine.
I use FT232R chip, but any ready USB/RS232 converter with TTL output can be used (e.g. Mini USB Adapter from Arduino).
Outputs from module can be connected directly to TxD i RxD pins in ATmega8 microcontroller. If USB/RS232 converter hasn't TTL output, any level conveter must be used (e.g. on MAX232 chip).
Files to download:
OTRSP to BCD converter all files Zip file consists full Kicad and Bascom AVR projects 
File version: 1.00, Date: 2013-12-31, File size: 279 kb