Figure A.35 shows a 3-bit up counter. A counter that counts in the opposite direction (that is, 7, 6, ..., 1, 0, 7, ...) is called a down counter. A counter capable of counting in both directions under the control of an UP/DOWN signal is called an up/down counter. Show a logic diagram for a 3-bit up/down counter that can also be preset to any state through parallel loading of its flip-flops from an external source. A LOAD/COUNT control is used to determine whether the counter is being loaded or is operating as a counter.

LO1