The book starts out with a top-level discussion of the structure and organization of embedded computers as computers, the fetch-execute cycle, memory, Input/output. We focus on classical cpu architectures, while also looking at Field Programmable Gate Array (FPGA) and System on Chip (SoC) approaches. This leads us to the discussion of software for embedded. There are several differences here between embedded software and software in general. Most embedded systems are resource-constrained, but this is becoming less of an issue. Embedded systems generally require real-time response, and operate in a world where the timing of the result is as or more important than its accuracy. The correct answer, late, can be worse than an approximate answer on time.
Embedded systems have elements of hardware and software, and these are brought together into a working system. The systems engineering process, from requirements to testing and post-deployment support is discussed. There are known approaches that work. Software is a different animal than hardware, but the top-level principles for developing and testing derive from the same principles. Programmable hardware, in terms of FPGA’s and SoC’s introduce complexity, but can be addressed by the same engineering best practices.
Embedded systems have their own set of standards, and their own unique issues in security, but an embedded computer is also a computer. Virtualization has added new capabilities to embedded systems.
We will look at some real commercial products, both chips and systems. We will also consider failure cases, to learn, ideally, from others’ mistakes. We learn more from failures than from successes. This book discusses the “what” of embedded systems, and the follow on volume will discusses the “how”. There is necessarily some overlap in the material.
