Fsm3onehot

The following is the state transition table for a Moore state machine with one input, one output, and four states. Use the following one-hot state encoding: A=4'b0001, B=4'b0010, C=4'b0100, D=4'b1000.

Derive state transition and output logic equations by inspection assuming a one-hot encoding. Implement only the state transition logic and output logic (the combinational logic portion) for this state machine. (The testbench will test with non-one hot inputs to make sure you're not trying to do something more complicated).

 

StateNext stateOutputin=0in=1

A	A	B	0
B	C	B	0
C	A	D	0
D	C	B	1

module top_module(
    input in,
    input [3:0] state,
    output [3:0] next_state,
    output out); //

    parameter A=0, B=1, C=2, D=3;

    // State transition logic: Derive an equation for each state flip-flop.
    assign next_state[A] = (state[A] & ~in) | (state[C] & ~in);
    assign next_state[B] = (state[A] & in) | (state[B] & in) | (state[D] & in);
    assign next_state[C] = (state[B] & ~in) | (state[D] & ~in);
    assign next_state[D] = (state[C] & in);

    // Output logic: 
    assign out = (state[D] == 1'b1) ? 1'b1 : 1'b0;

endmodule