What is GPIO and how is it configured?

GPIO (General Purpose Input/Output) pins can be software-configured as digital inputs or outputs. Configuration involves: Direction (input vs output), Pull-up/pull-down resistors (define default input state), Drive strength (current capability for outputs), and Alternate function selection (UART, SPI, etc.). As input, GPIO reads external digital signals (buttons, sensors). As output, it drives LEDs, relays, or control signals. GPIOs may have interrupt capability for edge or level detection. Proper configuration prevents floating inputs and excessive current draw.