Book Image

Embedded Systems Architecture - Second Edition

By : Daniele Lacamera
5 (1)
Book Image

Embedded Systems Architecture - Second Edition

5 (1)
By: Daniele Lacamera

Overview of this book

Embedded Systems Architecture begins with a bird’s-eye view of embedded development and how it differs from the other systems that you may be familiar with. This book will help you get the hang of the internal working of various components in real-world systems. You’ll start by setting up a development environment and then move on to the core system architectural concepts, exploring system designs, boot-up mechanisms, and memory management. As you progress through the topics, you’ll explore the programming interface and device drivers to establish communication via TCP/IP and take measures to increase the security of IoT solutions. Finally, you’ll be introduced to multithreaded operating systems through the development of a scheduler and the use of hardware-assisted trusted execution mechanisms. With the help of this book, you will gain the confidence to work with embedded systems at an architectural level and become familiar with various aspects of embedded software development on microcontrollers—such as memory management, multithreading, and RTOS—an approach oriented to memory isolation.
Table of Contents (18 chapters)
1
Part 1 – Introduction to Embedded Systems Development
4
Part 2 – Core System Architecture
8
Part 3 – Device Drivers and Communication Interfaces
13
Part 4 – Multithreading

Scheduler implementation

The architecture of the system depends on the way the scheduler is implemented. Tasks can be running in a cooperative model until they voluntarily decide to yield the CPU to the next task, or the OS can decide to trigger an interrupt to swap the running task behind the scenes, applying a specific policy to decide the interval in between task switches and the priority for the selection of the next task. In both cases, the context switch happens within one of the supervisor calls available, set to decide which tasks to schedule next, and to perform the context switch. In this section, the full context switch procedure through PendSV will be added to our example, and then a few of the possible scheduling policies will be analyzed and implemented.

Supervisor calls

The core component of the scheduler consists of the exception handler associated with the system interrupt events, such as PendSV and SVCall. On Cortex-M, a PendSV exception can be triggered at...