Whilst its only recapped on in some of the lectures, it assumes knowledge from the engineering module, which the computer science Computer Organisation and Architecture (CS132) also covers.

A fair bit of this information is already in CS132 Logic Page. There are some engineering specific things, and stuff that's just handy to have on one page.

Boolean Algebra Laws

There are several laws of boolean algebra which can be used to simplify logic expressions:

NameAND formOR form
Identity Law
Null Law
Idempotent Law
Inverse Law
Commutative Law
Associative Law
Distributive Law
Absorption Law
De Morgan's Law
  • Can go from AND to OR form (and vice versa) by swapping AND for OR, and 0 for 1

Most are fairly intuitive, but some less so. The important ones to remember are:


SR Latch

  • When is asserted, goes high.
  • When is asserted, goes low.
  • When both are de-asserted (low and low), holds its value
  • When both are asserted (high and high), and goes low (not intended!)

D latch

Passes through the input whenever is high, and hold when is low.

D Flip Flop

Will copy the input to the output at rising edges of . Bit storage.