“Since the new 32-Bit Arduino Uno R4 has arrived, it is time to make a glorious farewell project to the classic 8-Bit UNO R3, by using all the pins and turning it into a handheld BASIC computer, quite similar to a ZX81 from the 80s! It is finally time to build a badge that uses up all the pins and shows that an 8-Bit microcontroller is in fact a tiny computer! The badge form factor makes it ideal for your next meetup with fellow makers!
His project begins with Tiny Basic, a complete BASIC programming environment for Arduino. Tiny BASIC barely fits on an ATmega 238p on its own, so Clem utilizes a secondary chip to read the keyboard and drive the screen, offloading these tasks from the main processor running the operating system. This ensures that we have 1k of RAM left for writing programs (in the same ballpark as the Zx81). To make it fully portable, Clem incorporates a second processor to handle the keyboard and LCD screen, allowing the main microcontroller to focus solely on the operating system.”