Embedded Multitasking

138 Chapter 3

the communications needs of the system and determine the likely stor-

age requirements.

If we examine our clock project in light of these requirements, we

come up with the following notes for our design file:

INPUT PERIPHERAL

Buttons: These inputs generate dynamic values a

single bit in length. There are 6 inputs, with a

maximum rate of 3 presses per second, an average of

1 press per second, and a peak rate of 3 per sec-

ond. That means a storage requirement of 18 bits

for a worst case.

60 Hz: This input is the 60-Hz line clock for the

system. Its rate does not change under normal oper-

ating conditions, so the maximum, average, and peak ...