Microsoft Word - Digital Logic Design v_4_6a

Step 4 – Excitation Input and Output Equation
Note: T= y (xor) y+

Present State Ext. Input Next State

y 2 y 1 y 0 UD D 2 =y 2 + D 1 =y 1 + D 0 =y 0 +

0 0 0 0

0 0 0 1

0 0 1 0

0 0 1 1

0 1 0 0

0 1 0 1

0 1 1 0

0 1 1 1

1 0 0 0

1 0 0 1

1 0 1 0

1 0 1 1

1 1 0 0

1 1 0 1

1 1 1 0

1 1 1 1

Notes:

1) State Assignment: Binary value (y2y1y0) Equivalent to the

count.

2) Output: same as state variables (y2y1y0).

y 2 y 1 y 0

UD

000 001

(^111 110)

0

0

0

010

0

1

0

1

011

100

1 0

1

1

1

101

1

0

1

0