Page 121 - Bebop to The Boolean Boogie An Unconventional Guide to Electronics Fundamentals, Components, and Processes

102 Chapter Ten

c c cdy

00

01

11

10

c x 00 01 Ill I 10 cdy IO0 01, 11 10 c

I
y=(b&c)I(a&b&d) y= (a &d) &&c) Y=(b&d)

Figure 10-7. Additional Karnaugh Map grouping possibilities

Incompletely Specified Functions
In certain cases a function may be incompletely specified: that is, the
output may be undefined for some of the input combinations. For example, if
the designer knows that certain input combinations will never occur, then the
value assigned to the output for these combinations is irrelevant. Alternatively,
for some input combinations the designer may simply not care about the value
on the output. In both cases, the designer can represent the output values