Answer Happy

Complete 1, 2, 3, 4, and 5.
1. Design a sequential machine for the combinational lock described in section 3.6.1 30 25 5 20 10 15 (a) Figure 3.23 Combination lock 1. Identify states 2. State diagram 3. State assignment 4. State table 5. Sequential Machine 3.6.1 A Simple Example: The Combination Lock A simple example shows the difference between combinational logic structures and sequential logic structures. Suppose one wishes to secure a bicycle with lock, but does not want to carry a key. A common solution is the combination lock. The person memorizes a "combination" and uses it to open the lock. Two common types of locks are shown in Figure 3.23. In Figure 3.23a, the lock consists of a dial, with the numbers from 0 to 30 equally spaced around its circumference. To open the lock, one needs to know the "combination.” One such combination could be: R13-L22-R3. If this were the case, one would open the lock by turning the dial two complete turns to the right (clockwise), and then continuing until the dial points to 13, followed by one chapter 3 Digital Logic Structures 30 25 5 Gooola 4) 1 84 20 10 15 (a) (b) Figure 3.23 Combination locks. complete turn to the left (counterclockwise), and then continuing until the dial points to 22, followed by turning the dial again to the right (clockwise) until it points to 3. At that point, the lock opens. What is important here is the sequence of the turns. The lock will not open, for example if one performed two turns to the right, and then stopped on 22 (instead of 13), followed by one complete turn to the left, ending on 13, followed by one turn to the right, ending on 3. That is, even though the final position of the dial is 3, and even though R22-L13-R3 uses the same three numbers as the combination R13-L22-R3, the lock would not open. Why? Because the lock stores the previous rotations and makes its decision (open or don't open) on the basis of the the history of the past operations, that is, on the correct sequence being performed.