Chapter 5 – Sequential Circuits

Optimization: Example 2: One Hot Assignment
• Equations read from 1 next state variable
entries in table:
D 0 = X(Y 0 + Y 1 + Y 3 ) or X Y 2
D 1 = X(Y 0 + Y 3 )
D 2 = X(Y 1 + Y 2 ) or X(Y 0 + Y 3 )
D 3 = X Y 2
Z = XY 3 Gate Input Cost = 15
• Combinational cost intermediate plus cost
of two more flip-flops needed.
Chapter 5 - Part 2 31
Map Technology
• Library:
• D Flip-flops
with Reset
(not inverted)
• NAND gates
with up to 4
inputs and
inverters
X
Clock
Reset
• Initial Circuit:
D
C
R
D
C
R
Y 1
Y 2
Z
Chapter 5 - Part 2 32
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