 User Interface | Human interface on SAM3X Arduino: |
| Universal Synchronous Asynchronous | Receiver Transmitter (USART) |
| Power Management Controller (PMC) | |
| Peripheral Parallel Input/Output (PIO) Controller | |
| Universal Asynchronous Receiver Transceiver (UART) | The Universal Asynchronous Receiver Transmitter features a two-pin UART that can be used for communication and trace purposes and offers an ideal medium for in-situ programming solutions |
| Universal Synchronous Asynchronous Receiver | Transmitter (USART) |
 Clock Management | |
 Generic Clock Management | Generic clocks are configurable clocks which run outside the system clock domain |
| Oscillator Management | This group contains functions and definitions related to configuring and enabling/disabling on-chip oscillators |
| PLL Management | This group contains functions and definitions related to configuring and enabling/disabling on-chip PLLs |
 System Clock Management | See Quick Start Guide for the System Clock Management service (SAM3A) |
| Power Manager (PM) | This is a stub on the SAM Power Manager Control (PMC) for the sleepmgr service |
| Compiler abstraction layer and code utilities | Compiler abstraction layer and code utilities for AT91SAM |
| Preprocessor - Macro Repeat | |
| Preprocessor - Stringize | |
| Preprocessor - Token Paste | |
| Global interrupt management | This is a driver for global enabling and disabling of interrupts |
| Deprecated interrupt definitions | |
| Atmel part identification macros | This collection of macros identify which series and families that the various Atmel parts belong to |
| AVR UC3 parts | |
| AVR XMEGA parts | |
| megaAVR parts | |
| SAM parts | |
| Sleep manager | The sleep manager is a service for ensuring that the device is not put to sleep in deeper sleep modes than the system (e.g., peripheral drivers, services or the application) allows at any given time |
| USB Stack | This stack includes the USB Device Stack, USB Host Stack and common definitions |
| USB Stack Host | This module includes USB Stack Host implementation |
| USB Host Driver (UHD) | The UHD driver provides a low-level abstraction of the host controller hardware |
| USB host Controller (UHC) | The UHC provides a high-level abstraction of the usb host |
| Implementation of UHC | Internal implementation |
| USB Host Controller (UHC) - Prerequisites | Common prerequisites for all USB hosts |
| USB Host Controller (UHC) - Example code | Common example code for all USB hosts |
| USB Device Controller (UHC) - Workflow | Common workflow for all USB devices |
 USB Host Interface (UHI) | The UHI provides a common API for all classes, and this is used by UHC for the main control of USB host interface |
 UHI for Communication Device Class | Common APIs used by high level application to use this USB host class |
| Implementation of UHI Communication Device Class | Class internal implementation |
| Interface with USB Host Core (UHC) | Define and functions required by UHC |
| UOTGHS OTG Driver | UOTGHS low-level driver for OTG features |
| Atmel USB Identifiers | This module defines Atmel PID and VIDs constants |
| USB Protocol Definitions | This module defines constants and data structures provided by the USB 2.0 specification |
| Communication Device Class Definitions | |
| Generic board support | The generic board support module includes board-specific definitions and function prototypes, such as the board initialization function |
| General Purpose Input/Output | This is the common API for GPIO |
| Common IOPORT API | See Quick start guide for the common IOPORT service |
1.8.5