raspberry-pi

Goal: Interface hardware peripherals (sensors, actuators, radios) with a Raspberry Pi running a standard Linux OS (Raspberry Pi OS).

1. Pinout & Buses

The 40-pin GPIO header provides multiple buses.

• Levels: GPIO logic is 3.3V. Connecting 5V signals directly will destroy the Pi.
• I2C: Pins 3 (SDA) and 5 (SCL). Requires enabling via raspi-config. Built-in pull-up resistors (1.8kΩ) exist on these pins.
• SPI: Pins 19 (MOSI), 21 (MISO), 23 (SCLK), 24 (CE0), 26 (CE1).
• UART: Pins 8 (TX) and 10 (RX). Usually mapped to /dev/serial0 (disables Bluetooth console on Pi 3/4).

2. Software Interfacing (Python)

Prefer gpiozero for simple UI/sensors and smbus2 or spidev for deep bus control.