TABLE OF CONTENTS We will discuss software and communications issues from an architectural point of view. While some simple portable electronic devices can be created without the need for software or external communications, higher complexity products will generally contain either embedded software or will be loaded with general purpose software applications and will have provisions for external communications protocols.
Portable electronic devices that operate with a minimum of buttons to achieve a focused functionality are highly desirable, as discussed at several points in this text. In very simple products that perform a very limited functionality, such as a laser pointer, there is no need for a user interface beyond a single button, and there is no logic control in the system beyond. In such cases, the system does not have a software component.
In most products, however, some type of microcontroller is needed to provide a more complex set of logical operations. Thus, embedded software is needed to handle the complexity of user interaction. In these cases, the user will still interact largely with buttons or a simple character display and will not be aware of the role that software plays in the product functionality.
In the most sophisticated products, such as PDAs and notebook computers, the user will interact directly with application software and even the operating system. In these cases, the user considers the system software and the user interface to be identical.
There are a wide variety of conceptual representations to show how software components are...
