Below is a flip-flop based circuit (note the different kinds of flop-flops in us

Question

Below is a flip-flop based circuit (note the different kinds of flop-flops in use). Inputs to the circuit (besides the Clk clock signal) are A and B. Y is the output, and A1, B1 and B2 are intermediate points within the circuit.

All flip-flops used in this circuit are synchronous - that is, values are accepted on their inputs (and processed) when the clock signal is high, but results are not displayed on their Q and Q' outputs until the clock signal goes low, This isvery important in following the operation of the circuit!

Below the circuit diagram is a pulse train, with the trains for A, B and Clk filled in. Also filled in are the initial values for A1, B1, B2, and Y.

You should complete the pulse trains for A1, B1, B2 and Y and enter the sequences in the yellow area in the spaces provided below as groups of ten 1's and 0's (for example, 1100110000).

Recommendation on how to tackle this problem: Do the trains one at a time: do the entire left-to-right train for A1, followed by that for B1, then for B2, and finally for Y. If you try to do the first clock cycle for A1, B1, B2 and Y, and then move on to the next clock cycle, you will get hopelessly confused! Do not be distracted by all the trains. At any one time, you are looking at inputs from only one (or, in one case, two) other train, in addition to the clock signal. Examples: when working on A1, you need only look at signal A and the Clk signal. When working on Y, you have to look at the trains for A1 and B2, plus the Clk signal.

The below Excitation Table is waiting to be filled in according to the following specifications:

The desired circuit is a strange kind of 3-bit binary "counter" - it counts in the following sequence: 001 to 110 to 010 to 101 to 100 and rolls over to 001.

Any states not listed above (000, 011 and 111) are never used.

The circuit should be implemented using synchronous T flip-flops.

After you have filled in the empty cells in the excitation table, enter the values you entered in each column as a string of eight characters (each character can be "0", "1", or "X" (use a capital X) in the spaces provided below (an example would be 10XXX001):

The train for A1 The train for B1 The train for B2 The train for Y SET A1 CLR B1 D SET Q CLR CLR CIk Clk A1 B1 B2

Explanation / Answer

Exitation table:

PRESNET STATE NEXT STATE Flip-Flop Inputs A B C A(t+1) B(t+1) C(T+1) TA TB TC 0 0 0 x x x x x x 0 0 1 1 1 0 1 1 1 0 1 0 1 0 1 1 1 1 0 1 1 x x x x x x 1 0 0 0 0 1 1 0 1 1 0 1 1 0 0 0 0 1 1 1 0 0 1 0 1 0 0 1 1 1 x x x x x x

Related Questions

Navigate

• Browse (All)
• Browse B
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.