This is the simplest version of a fully working Intel 8085-based microprocessor system. With only 3 chips, and an Arduino, the circuit can be built on a breadboard ... but it's enough for simple ...

Abstract: For the period 1971-1975, the industrial design engineers primarily studied the 4004, 8008 and 8080 microprocessors for the purposes of building control circuits ... 8085 microprocessor ...