he used an Arduino Mega as a debugger, making the SBC an Arduino shield itself. Using such a common header pinout for the Z80 computer allows it to be used with a variety of readily-available ...
It’s a significant update. The Arduino UNO and Arduino Mega 2560 update the Duemilanove and Mega respectively. They now use an ATMega8U2 instead of an FTDI USB to serial converter chip.