Question 1

create a 4 bit down counter that counts down from 9 to zero and then count 10. 11, 12 and then back to 9. You will design the logic of the circuit and also a chip level diagram. Your circuit will have a 4 bit output. It will be a finite state machine:

Any input to your circuit other than zero through nine (0000 1001) ten, eleven and twelve(10101100), should reset the output to nine (1001). Your tasks are to document the following. Create a state transition diagram for your finite state machine based counter (do not forget transitions to state nine from unused states)

Specify the truth table (assuming D Flip Flops).

Derive necessary Boolean equations (using kmaps)

Draw gate-level logic diagram (logic gate symbols)