Embedded Systems and Computer Architecture

2

Logic expressions

We begin our discussion of logic by asking how we can make an automatic device for controlling access to a bank vault. In finding an answer to this question, we shall arrive at a form of algebraic expression that always evaluates to either 0 or 1. To arrive at the simplest form of these expressions, you can learn a graphical method and a tabular method for simplifying logic expressions.

2.1 Logic – the bank vault

Three employees of a bank have access to the vault: the Manager, the Assistant Manager, and the Chief Cashier. In order to obtain access to the vault, any two of these persons must present themselves before an incorruptible person, the controller, who decides if access to the vault is permitted.

The controller makes ...