Microcontrollers have become affordable and powerful enough that developers for various applications no longer need to write low-level code. They can now write code at a higher level, like PC application developers do. To achieve this, embedded software developers have two options: HALs and APIs, which provide different methods for writing code at a higher level of abstraction.
Hardware Abstraction Layers (HALs) are not tools themselves but rather software layers or libraries that facilitate the interaction between software and hardware. They are implemented as part of the software development process for embedded systems. HALs can be developed in-house by the development team or provided by hardware manufacturers or third-party vendors.
Application programming interfaces (APIs) are sets of tools and protocols that enable developers to create applications. They provide a high-level interface for developers to interact with software components, offering functions and methods for various operations.
The primary purpose of HALs is to simplify software development by shielding developers from the low-level details of hardware implementation. They offer a set of functions and APIs (Application Programming Interfaces) that enable software to communicate with the hardware without requiring in-depth knowledge of its specific characteristics.
APIs and HALs have distinct roles in software development. The HAL acts as an intermediary between low-level drivers and higher-level software stacks, offering a unified interface for essential software components like RTOS, USB, ethernet, and file systems. It serves as a bridge, enabling seamless communication between existing drivers and higher-level code. On the other hand, APIs serve as toolkits for high-level developers, facilitating the efficient creation of application code. They provide standardized interface code for managing real-time system behavior and accessing common components like serial communication and file operations.