Flip-flops: latch
	Characteristic table (corresponds to truth table):
	Q+ represents the NEW value of Q
		R	S	Q+
		0	0	Q
		0	1	1
		1	0	0
		1	1	undefined						(Fig. B.12)
	When both set and reset are 0, Q is unchanged.
	When only S is 1, Q becomes 1.
	When only R is 1, Q becomes 0.
	When both R and S are 1, the behavior is undefined.