Question

There are two inputs A, B, and one output Z in a sequential circuit. The output remains a constant value unless one of the following conditions are met:

a) If the input sequence is AB = 01, 11, it causes the output to become ‘0’
b) If the input sequence is AB = 10, 11, it causes the output to become ‘1’
c) If the input sequence is AB = 10, 01, it causes the output to change value (toggle)

The notation of AB = 01,11 means A=0, B=1 followed by A=1, B=1. Derive a MOORE state graph and state table for the above-mentioned sequential circuit.

Answer 1

To create a MOORE state graph and state table, define states based on the output Z and list transitions based on input AB sequences. Two states, S0 and S1, represent output values 0 and 1, respectively, with transitions determined by specified conditions.

Step-by-step explanation:

The task is to derive a MOORE state graph and state table for a sequential circuit with given conditions for output changes based on the input sequences. In a Moore machine, the outputs are determined solely by the current state. Therefore, we begin by defining states based on the current value of the output and the transitions between these states based on the given input conditions.

• State S0 with Output Z=0
• State S1 with Output Z=1

Transitions based on inputs AB:

• From S0 to S1 if AB=10
• From S1 to S0 if AB=01
• For AB=11 the output becomes 0 in S0 and 1 in S1
• From S0 to S1 or from S1 to S0 if AB=10 followed by 01 or vice versa (toggle)

The state table has these columns: Present State, Next State (Based on inputs AB=00, 01, 10, 11), and Output Z.