Figure A.35 shows an asynchronous 3-bit up-counter. Design a 4-bit synchronous up- counter, which counts in the sequence 0, 1, 2, ..., 15, 0.... Use T flip-flops in your circuit. In the synchronous counter all flip-flops have to be able to change their states at the same time. Hence, the primary clock input has to be connected directly to the clock inputs of all flip-flops.

LO1