FreeRTOS & Networking

To build robust IoT devices, you need a solid understanding of real-time multitasking and lightweight networking protocols.

FreeRTOS

FreeRTOS is the real-time operating system that underlies ESP-IDF. It manages tasks, queues, semaphores, and timing.

• FreeRTOS Official Documentation: The authoritative source on how FreeRTOS works.
• Mastering the FreeRTOS Real Time Kernel (PDF): An excellent, comprehensive book provided for free by the FreeRTOS creators.
• ESP-IDF FreeRTOS Additions: Espressif has customized FreeRTOS to support the ESP32's dual-core architecture (SMP). Read this to understand ESP-specific features like pinning tasks to a specific core.

IoT Networking (MQTT)

MQTT is the standard messaging protocol for the Internet of Things. It is lightweight, publish-subscribe based, and perfect for microcontrollers.

• MQTT Essentials (HiveMQ): A brilliant, easy-to-read series of articles that explain exactly how MQTT works, covering topics like topics, QoS levels, and retained messages.
• Mosquitto: A popular, lightweight open-source MQTT broker. Great for running locally on a Raspberry Pi.
• ESP-MQTT Documentation: The official ESP-IDF documentation for the MQTT client library.