Programming is an essential engineering skill. To almost any engineer, it is as
important as circuit design to an electrical engineer, as statistics to a civil engineer, and
as heat transfer to a chemical engineer. The engineer has to program in high-level
languages to solve problems. He or she also should be able to read assembly-language
programs to understand what a high-level language does. Finally, he or she should
understand the capabilities of a microcontroller because they are components in many
systems designed, marketed, and maintained by engineers. The first goal of this book
then is to teach engineers how a computer executes instructions. The second goal is to
teach the engineer how a high-level language statement converts to assembler language.
A final goal is to teach the engineer what can be done on a small computer and how the
microcomputer is interfaced to the outside world. Even the nonprogramming engineer
should understand these issues. Although this book is written for engineers, it will serve
equally well for anyone, even hobbyists, interested in these goals.
The reader is taught the principles of assembly-language programming by being
shown how to program a particular microcomputer, the Motorola 6812. The important
thing about the 6812 is that it has a straightforward yet powerful instruction set, midway
between smaller and more powerful microcontrollers; from it the reader can adjust to
these smaller or more powerful microcontrollers. The best way to learn these principles
is to write a lot of programs, debug them, and see them work on a real microcontroller.
This hands-on experience can be inexpensively obtained on the 6812. Several 6812
boards, which do everything described in this book, are available for under $100. (This
price doesn't include the personal computer that hosts the 6812 target system.)