Page 15 - Embedded Microprocessor Systems Real World Design

Special Introduction to the

Third Edition

Since the first edition of this book was published, the embedded microprocessor
world has changed. Entire families of microprocessors have become obsolete, along
with their associated peripheral devices. This march of technology has the dis-
advantage of making examples using those devices obsolete as well. In some cases,
I have kept examples that used some of these older parts because they provide a
clearer means of communicating a concept than examples using newer, more
complex devices. In general I have tried to use parts that are still in production for
the examples, although some of these parts may be nearing their end of life and
not as common as newer parts.
In addition to using some older devices in examples, the text still refers to older
logic devices as well. These latches, gates, and registers provide a well-understood
means of illustrating an interface mechanism that tends to become overly complex
if all the component parts must be explained in detail before the desired concept
can be covered. In most modern circuits, these functions have been taken over by
programmable logic or custom ICs. The concepts, however, are still valid even if
the implementation technology has changed.
Owing to these advances in technology, I have added some new examples, using
updated parts, to the book. Readers of the first and second editions of the book
will note that some original examples have been replaced with examples that use
these newer parts. Of course, there is no guarantee that any current production
part will still be in production by the time you read this, but that is the nature of
the electronics industry!

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