What is a State Transition Table?
A State Transition Table is similar to a Truth Table, but it additionally stores:
- Current and Next State of the flip-flop(s)
- Current state values are typically written with the inputs, while next state values with outputs
How to Generate a State Transition Table from a State Transition Diagram?
- Count the total number of states/circles in the state diagram.
- These states represent \(\mathsf{2^n}\) combinations of flip-flop values, where \(\mathsf{n=}\) number of flip-flops.
- These \(\mathsf{n}\) flip-flops are used to store the current state and next state of the circuit.
- List all the current state variables and inputs on the left side of the table.
- Each column represents one input or one flip-flop.
- Total rows in the table are equal to \(\mathsf{2^n}\), where \(\mathsf{n=}\) number of inputs + number of flip-flops.
- List all the next state variables and combinational outputs on the right side of the table.
- Each column represents one output or one flip-flop.
- Fill out the outputs or next state variables in each row by following the arrows in the state diagram.
Example: Generate a State Table from the State Diagram
Reciprocating our analysis example to showcase design, we have the following state diagram:
Master state machine analysis with our interactive step-by-step animation. Beginning with the complete state diagram, each highlighted green arrowhead guides you through mapping the transitions row by row to populate the next state and output columns in the state table. Explore the animation below to see how every graphical path translates into a fully completed state table.