# GPIO Foundations ## What is GPIO? **General Purpose Input/Output** Standard digital interface to the outer world. The most basic peripheral: making pins go high or low, and reading whether they're high or low. --- ## Configurations: Direction - **Output** — you drive the pin (e.g., turn on an LED) - **Input** — you read the pin (e.g., detect a button press) --- ## Configurations: Output ### Modes - **Push-pull** (typically default) — actively drives the pin high and low - **Open-drain** — actively drives low, but floats when "high" (needs external pull-up) <br/> <br/> ### Drive Strength How much current the pin can source or sink. Higher drive strength = brighter LED, but more power consumption. --- ## Configurations: Input ### Internal Pull Resistor - **Pull-up** — pin reads high when nothing is connected; button pulls it low - **Pull-down** — pin reads low when nothing is connected; button pulls it high - **Floating** — no pull resistor; pin state is undefined when nothing is connected --- ## GPIO Actions - **Input** — read current state (**high** / **low**) - **Output** — change output state (**high** / **low**)
The Embedded Rustacean · Rust Week 2026
The Embedded Rustacean · Rust Week 2026
The Embedded Rustacean · Rust Week 2026