> Goal: find a minimum gazump determine
Goal: find
> Why We Need to Find all in all PIs?
f(w,x,y,z) = xy +wxy+xyz+wyz
1. Are all terms PIs?
2. Is the form optimal?
3. Is the form unique?
= xy+xz+wxy+wyz
= xy+xz+wxy+wxz
= xy+xz+wxz+wyz
> How We Find Them?
= Quines tabular: start with minterm, the smallest I
Quines
start
= Iterated consensus: complete addition theorem 4.5.1
Iterated
complete
= Recursive: complete sum theorem 4.6.1
Recursive: complete
ENEE 644
1
Quine-McCluskey Method
Problem: Given a Boolean usance f (may be
Problem:
(may
incomplete), find a minimum terms SOP formula.
cost
# of literals
Q-M Procedure:
1.
2.
2.
3.
3.
Generate all the PIs of f, {Pj}
Generate all the
Generate all the minterms of f, {mi}
Generate all the
reconstruct the Boolean constraint matrix B, where Bij iis 1 if
s
Boolean
mi? Pj and is 0 otherwise
4. Solve the minimum column covering problem for B
4. Solve
ENEE 644
2
casing: Quine-McCluskey Method
Example: Quine
f(w,x,y,z) = xy + wxy + xyz + wyz
wxy
xy
xz
wxyz
1
1
wxyz
1
wxyz
1
wxyz
1
wxyz
wxz wyz wyz
1
1
1
{xy, xz,wxy, wxz},
{xy, xz,wxy, wyz},
{xy, xz,wxz, wyz}.

1
1
wxyz
wxyz
1
1
wxyz
wxyz
minimum cover(s):
1
1
1
ENEE 644
1
3
Two-Level Logic Synthesis
Two
-- Unate screen Problem
Unate and Binate
nf
> A knead f(x1,xixn) is positive unate iin xi iif
forge f(x
positive
its cofactor f x includes f x
its
i
i
Negative unate iis define in a similar way. If a function is
s
incomplete positive unate nor negative unate in a variable, it
is called binate in this variable.
binate
A function is positive/negative unate iif it is so for all
f
function positive/negative
variables, otherwise it is called binate.
binate
> Example: f(x,y,z) = xy + xz + yz
Example: f(x,y,z)
=
=
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