External module for cctalk and MDB protocol on ATXmega, serial printer and communication with base module on ATMega2560.
Base module: ATMega2560 human interface, matrix keyboard, I2c display, temp. sensor SMT160-30. This shout be a base for next modular extension.
The MDB protocol is C-programmed in in section, coin changer, bill validator, cashless device. I have of course the source data. ccTalk and printer must be programmed complete.