Microprocessors, the heart of digital computers, have been in a constant state of evolution since Intel developed the first general-purpose microprocessors in the early 1970s. Intel’s four-bit 4004 made history, because it was a complete microprocessor on a single chip at a time when processor modules for minicomputers filled multiple circuit boards. Over the past three decades, the complexity and throughput of microprocessors has increased dramatically as semiconductor technology has improved by leaps and bounds. Hundreds of microprocessors have come and gone over the years. There are many different architectures on the market today, each with its own claims of superior performance, lower cost, and reduced power in its intended applications.
When looking back on three decades’ worth of development and the state of microprocessors today, several microprocessor families are especially worth exploring as instructional examples of basic computer architecture. Some of these families are the ancestors of very popular and widespread designs that are used to this day. Familiarity with these classic microprocessors can make it easier to learn about contemporary products that are either improved versions of the originals or members of other families that share common traits. Alternatively, some of these families are worthy of note because of their important role in permeating everyday life with microprocessors in places that most people rarely think of as computerized: cars, microwave ovens, dishwashers, and VCRs. This chapter provides information that is both historical and directly relevant to contemporary digital systems design. Five classic microprocessor architectures are presented: Motorola 6800, Intel 8051, Microchip PIC, Intel 8086, and Motorola 68000. All of these architectures are in use today in varying forms, and each represents a different perspective on how microprocessors can accomplish similar tasks. A future design challenge may be addressed directly by one of these devices, or the solution
may employ architectural concepts that they have helped to bring about.
When looking back on three decades’ worth of development and the state of microprocessors today, several microprocessor families are especially worth exploring as instructional examples of basic computer architecture. Some of these families are the ancestors of very popular and widespread designs that are used to this day. Familiarity with these classic microprocessors can make it easier to learn about contemporary products that are either improved versions of the originals or members of other families that share common traits. Alternatively, some of these families are worthy of note because of their important role in permeating everyday life with microprocessors in places that most people rarely think of as computerized: cars, microwave ovens, dishwashers, and VCRs. This chapter provides information that is both historical and directly relevant to contemporary digital systems design. Five classic microprocessor architectures are presented: Motorola 6800, Intel 8051, Microchip PIC, Intel 8086, and Motorola 68000. All of these architectures are in use today in varying forms, and each represents a different perspective on how microprocessors can accomplish similar tasks. A future design challenge may be addressed directly by one of these devices, or the solution
may employ architectural concepts that they have helped to bring about.
