Programming for Microprocessors

8

The control of most peripheral devices is a complex matter. So far, this

fact has been concealed by a very careful choice of peripherals, but in

this chapter the real problems of the area will be faced and illustrated

by a realistic practical example.

In previous chapters, all the devices chosen for discussion were in-

stantaneous in their response. Thus the setting of a switch could be

sensed at any time, and an LED display could absorb any data sent to

it at electronic speed.

In practice, most peripherals take finite times to react to any signal

from a microcomputer. There are two reasons:

• Some devices rely on mechanical motion. This categor ...