Synchronous vs Asynchronous Inputs
Synchronous input: Output will change after active clock edge Asychronous input: Output changes independent of clock
Flip-Flops often have async set, reset control.
D input is synchronous with respect to Clk
S, R are asynchronous. Q output affected by S, R independent of C. Async inputs are dominant over Clk. S,R inputs often called Pre (preset) and Clr (clear) inputs.