Question

Pre-Laboratorv Exercise: You are to design a state machine capable of controlling a 4-phase unipolar stepper motor. This motor operates by energizing one (or more) of four coils of wire at a time to rotate a magnetized shaft to predetermined positions. Let us call the four coils A, B, C, and D. To make the motor rotate properly, the coils need to be turned on (driven at logic "1") and off (driven at logic "O") in the following sequence: ABCD- 0011 0110 > 1100 10010011 Your task is to design a counter that will generate these outputs in this sequence. This may be accomplished either using four flip-flops where the output of each corresponds to one of the motor coils (e.g. A-Q3, B-Q2, etc.) or, since there are only four states, you may use two flip-flops and generate four output functions as combinations of the flip-flop outputs to drive the coils (e.g. A(Q1,Q0) B(Q1,00)-..., etc.). Hint: notice that C-A'andD-B. Your design should include an additional input for direction of the count. This will allow the motor to be rotated either clockwise or counter-clockwise. When Direction 0 follow the order listed above. When Direction- 1, reverse the direction of the count. Your design should also include an active-low reset signal that will cause the system to go to the state where ABCD-0011. Please consider using the asynchronous CLEAR and PRESET functions of the flip-flops for this task. should design the counter using 74LS74 D flip-flops.

Answer 1

Solution:

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Coler rue 0

A- dド R.