Design a 2-bit counter that, when f = 1, counts in the repeating sequence: 0, 2, 3, and when f = 0, counts in the reverse direction. Use T flip-flops. (a) Construct a state diagram or state table. (b) Specify a state assignment. (c) Construct the excitation table (that is, the version of the state-assigned table for T flip-flops). (d) Derive minimal Boolean expressions for flip-flop inputs and circuit outputs.