Instead of the relative horror of driving 40 LEDs with a single Arduino, [Martyn] bit the bullet and got a Maxim 7221 LED driver. Controlling 64 LEDs over a three-wire interface simplified the ...

[nanoflite] demonstrates the interface with an Arduino Uno and a Grove shield. The C64 is able to display the state of the LED, relay and servo outputs, as well as read the Arduino’s button and ...