Protocols

Communication protocols used with ESP32 — I2C, SPI, UART, OneWire, MQTT, and ESP-NOW

Reference guides for the communication protocols you will encounter when building ESP32 projects. Each page covers how the protocol works, which ESP32 pins to use, and common pitfalls.

  • I2C Protocol Reference

    ESP32 I2C reference — addressing, pin assignments, pull-ups, speed modes, common device addresses, and troubleshooting

  • SPI Protocol Reference

    ESP32 SPI reference — VSPI/HSPI buses, pin assignments, SPI modes, clock speeds, and troubleshooting

  • UART Protocol Reference

    ESP32 UART reference — baud rates, data formats, TX/RX wiring, UART port assignments, and troubleshooting

  • OneWire Protocol

    Technical reference for the Dallas OneWire (1-Wire) protocol on ESP32 — bus topology, addressing, timing, and common pitfalls

  • MQTT Protocol

    Technical reference for MQTT — topic hierarchy, QoS levels, retained messages, LWT, and ESP32 implementation details

  • ESP-NOW Protocol

    Technical reference for ESP-NOW — Espressif's peer-to-peer protocol for direct ESP32 communication without a WiFi router

  • BLE (Bluetooth Low Energy) Protocol

    Technical reference for BLE — GAP advertising, GATT services and characteristics, UUIDs, and ESP32 BLE stack details

  • 433 MHz RF Communication

    Reference and practical guide for 433 MHz RF communication with ESP32 — raw transmission, RC-Switch encoding, wiring, range tips, and troubleshooting