El escenario
A maker wants to drive an LED matrix from an ATtiny85 with minimal GPIO pins.
Qué hay en este dibujo
Lee las decisiones que hay detrás.
01
Use Charlieplexing to control 12 LEDs with only four pins
02
Add series resistors on each GPIO line for current limiting
Small LED matrix projects where GPIO pins are scarce and a compact display is needed.