Computer Laboratory – Course material 2008–09: Paper 2: Digital Electronics

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Paper 2: Digital Electronics

This Paper 2 course is taken by Part IA Computer Science Tripos students only.

Lecturer: Dr I.J. Wassell

No. of lectures and practical classes: 11 + 7

This course is a prerequisite for Operating Systems I and ECAD (Part IB).

Aims

The aims of this course are to present the principles of combinational and sequential digital logic design and optimisation at a gate level. The use of transistors for building gates is also introduced.

Lectures

Introduction. Semiconductors to computers. Logic variables. Examples of simple logic. Logic gates. Boolean algebra. De Morgan's theorem.
Logic minimisation. Truth tables and normal forms. Karnaugh maps.
Number representation. Unsigned binary numbers. Octal and hexadecimal numbers. Negative numbers and 2's complement. BCD and character codes. Binary adders.
Combinational logic design: further considerations. Multilevel logic. Gate propagation delay. An introduction to timing diagrams. Hazards and hazard elimination. Fast carry generation. Other ways to implement combinational logic.
Introduction to practical classes. Prototyping box. Breadboard and Dual in line (DIL) packages. Wiring.
Sequential logic. Memory elements. RS latch. Transparent D latch. Master-slave D flip-flop. T and JK flip-flops. Setup and hold times.
Sequential logic. Counters: Ripple and synchronous. Shift registers.
Synchronous State Machines. Moore and Mealy finite state machines (FSMs). Reset and self starting. State transition diagrams.
Further state machines. State assignment: sequential, sliding, shift register, one hot. Implementation of FSMs.
Circuits. Solving non-linear circuits. Potential divider. N-channel MOSFET. N-MOS inverter. N-MOS logic. CMOS logic. Logic families. Noise margin. [2 lectures]

Objectives

At the end of the course students should

understand the relationships between combination logic and boolean algebra, and between sequential logic and finite state machines
be able to design and minimise combinational logic
appreciate tradeoffs in complexity and speed of combinational designs
understand how state can be stored in a digital logic circuit
know how to design a simple finite state machine from a specification and be able to implement this in gates and edge triggered flip-flops
understand how to use MOS transistors

Recommended reading

* Harris, D.M. & Harris, S.L. (2007). Digital design and computer architecture. Morgan Kaufmann.
Katz, R.H. (2004). Contemporary logic design. Benjamin/Cummings. The 1994 edition is more than sufficient.
Hayes, J.P. (1993). Introduction to digital logic design. Addison-Wesley.

Books for reference:

Horowitz, P. & Hill, W. (1989). The art of electronics. Cambridge University Press (2nd ed.) (more analog).
Weste, N.H.E. & Harris, D. (2005). CMOS VLSI Design - a circuits and systems perspective. Addison-Wesley (3rd ed.).
Mead, C. & Conway, L. (1980). Introduction to VLSI systems. Addison-Wesley.
Crowe, J. & Hayes-Gill, B. (1998). Introduction to digital electronics. Butterworth-Heinemann.
Gibson, J.R. (1992). Electronic logic circuits. Butterworth-Heinemann.

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