Problem 4 (20 points) A Gray code is a sequence of binary numbers with the property that no more than one bit changes in going from one element of the sequence to another. For example, here is a 2-bit binary Gray code: 00, 01, 11, and 10. Using two D flip-flops and a PLA, construct a 2-bit Gray code counter that has two inputs: reset, which sets the counter to 00, and inc, which makes the counter go to the next value in the sequence. Note that the code is cyclic, so that the value after 10 in the sequence is 00. Problem 4 (20 points) A Gray code is a sequence of binary numbers with the property that no more than one bit changes in going from one element of the sequence to another. For example, here is a 2-bit binary Gray code: 00, 01, 11, and 10. Using two D flip-flops and a PLA, construct a 2-bit Gray code counter that has two inputs: reset, which sets the counter to 00, and inc, which makes the counter go to the next value in the sequence. Note that the code is cyclic, so that the value after 10 in the sequence is 00