Designing Embedded Hardware

Chapter 7. 68000-Series Computers

All is flux, nothing stays still.

—Heraclitus, Diogenes Laertius’ Lives of Eminent Philosophers

This chapter examines the Motorola 68000, a 32-bit processor that has been around for quite some time and has evolved into a plethora of controllers and embedded processors. The 68000 (also known as the 68k) is produced by Motorola (http://e-www.motorola.com) and is licensed by several other manufacturers. The range of 68000-based processors is large (check out the Motorola web site for a list of processors and their features). The number of applications that the 68000 has found its way into is enormous. You can even get 68000s as soft cores for FPGAs, which means that you place a 68000 CPU in the midst of your programmable logic, all on the one chip.

The 68000-series of processors are good general-purpose processors. They have a nice instruction set, are easy (and fun) to write code for, and are relatively easy to build computers around. They have large address spaces and asynchronous operation, allowing them to be interfaced to a wide variety of memory and peripherals of varying operating speeds. They are used in industrial control and monitoring and also in consumer electronics.

In this chapter, I look at the standard 68000 processor. More than likely, this is not the processor you will use in a design. Instead, you will probably choose a 68000-based integrated controller that better suits your needs. So, why look at a standard 68000 and not one of ...