Applied Embedded Electronics

Chapter 2. Architecting the System

This chapter defines the key parts of a system at the box level, discusses how to implement digital control at the core, and takes a detailed look at the criteria for a digital control unit (DCU). A procedure for selecting a microcontroller (MCU) is outlined as well. Later chapters detail the internal circuitry of those other boxes.

Topics covered here include:

• What a “mostly digital” system is

• Where DCUs are used

• Where multiple DCU devices are needed

• Differences between DCUs, MCUs, and microprocessors (MPUs)

• Alternative DCU methods, including field-programmable gate arrays (FPGAs), complex programmable logic devices (CPLDs), and application-specific integrated circuits (ASICs)

• Specialty methods for digital signal processing (DSP) and streaming data

• How to avoid data port bottlenecks

This chapter touches upon many topics that later chapters investigate in detail. Since these topics affect the architecture discussion, they need to be briefly defined for the reader to understand certain architecture strategies. We will start with some preliminary ideas and methods that need to be applied to all designs.

Preliminary Ideas

Defining a successful approach to a commercial product is the emphasis here. Certain common ideas need to be clarified at the start.

Simulate or Build

Generally there is no need to create a full simulation of an entire embedded controller system. The digital controller code will be simulated within the integrated ...