I'm trying to build a toggle that turns a 4 bit counter on or off. Here's where I'm at so far:
As you can see, I'm using a single D flip flop. Ideally I want one switch to disable the chip, and another to re-enable it.
Use the clocked output from the switch as the clock to a control flop.
A human pressing a button should be considered a separate clock domain. Therefore, two flops should be used to sync the input for CDC (Clock Domain Crossing). More about CDC here.