Question

Design a state machine that implements the following description:

Let’s design a simple controller for an elevator. The elevator can be at one of two floors: first or second. There is a button that controls the elevator (one input), and it has two values: up or down. Also, there are two lights in the elevator that indicate the current floor: blue for first, and yellow for second. At each time step, the controller checks the current floor and current input and changes floors and lights. Consider implementing this state machine as a Moore machine.

a. How many states do you need? How many outputs? Select variables to represent the state, input, and output signals

b. Draw the state diagram for your state machine

c. Draw the state table for your state machine

d. Create a truth table with multiple output columns. The inputs should be in button value and the present state value. The outputs should be the next state values and the light outputs.

e. Draw the final combinational and sequential circuit for the state machine and output using D flip flops, logic gates, and inverters. Use K-maps to minimize the circuit size.

Answer 1