System API
- App Image Format
 - Bootloader Image Format
 - Application Level Tracing
 - Call Function with External Stack
 - Chip Revision
 - Console
 - eFuse Manager
 - Error Code and Helper Functions
 - ESP HTTPS OTA
 - Event Loop Library
 - FreeRTOS Overview
 - FreeRTOS (IDF)
 - FreeRTOS (Supplemental Features)
 - Heap Memory Allocation
 - Memory Management for MMU Supported Memory
 - Heap Memory Debugging
 - ESP Timer (High Resolution Timer)
 - Internal and Unstable APIs
 - Inter-Processor Call (IPC)
 - Interrupt Allocation
 - Logging library
 - Miscellaneous System APIs
 - Over The Air Updates (OTA)
 - Performance Monitor
 - Power Management
 - POSIX Support (Including POSIX Threads Support)
 - Random Number Generation
 - Sleep Modes
 - SoC Capabilities
 - System Time
 - Himem
 - ULP Coprocessor Programming
 - Watchdogs
 
Code examples for this API section are provided in the system directory of ESP-IDF examples.