M. Morris Mano

This version of the book was published so long ago that some of the content is dated, but not its core: the basic principles behind designing the logic in the chips that are at the heart of the amazing spectrum of products we all enjoy and rely on in our lives.

If you ever wanted to understand the basics behind the design process, this book (or perhaps an updated version :-) would be the one to turn to.

The book starts with binary arithmetic, where 1 plus 1 does not equal 2, it equals 10. Why do computers use this? Because the bulk of the transistors in a computer chip are used as little switches, on or off, one or zero; this lends itself well to binary logic. But one needn’t know the underlying technology to understand the concept; binary arithmetic is straight out of mathematics.

It moves on to basic logic functions, the simple “gates” that serve as building blocks, for example, a 2-input OR gate where the output is “true” if either or both of its inputs are “true”. The technology underneath is again hidden, and the logic principles used are actually rooted in philosophy. There is an elegance to Mano’s descriptions, and I still recall the day when I became interested in pursuing this particular branch of computer engineering as a result of this book.

From there larger and more interesting combinations of functions can be built; “combinatorial” logic such as a circuit that adds two numbers. Mano has great descriptions of “Karnaugh mapping” to reduce the amount of logic as much as possible, a technique when applied broadly across all circuits, enables more logic to be squeezed onto a computer chip. Of course with modern synthesis tools, a lot of this mapping and optimization is now automated which didn’t exist at the time the book was written, but the technique is still the “bread and butter” for a logic designer.

From there Mano moves on to the concept of “time”, the internal “clocks” a computer chip uses – for example, the clock whose frequency is 1 GHz in a processor chip. These clocks advance the results of combinatorial logic from one pipeline stage to the next, and understanding a relatively simple set of principles in the design of the state machines and datapaths to do this enable one to design for essentially all applications.

Of course there are special circuits (notably analog, mixed-signal, and I/O) that require a different set of techniques and expertise, there is an art to the higher level architecture of these designs, and there is a tremendous amount of work needed on the lower level process technology that enables transistors to be built in the first place – frankly it’s a miracle that hundreds of millions of these are on computer chips smaller than a fingernail and that this technology is mass producible – but at the center of all of this is basic logic design. It has a simplicity that I’ve always liked, and my appreciation of that stems from Mano’s text.… (altro)