[SOLVED] D type flip flop as a toggle

[mrinalmani]

Is it reliable to construct a toggle-switch from a D-type flip flop by feeding back Q' to the input? I mean will the hold time, setup time etc etc cause a reliability issue? Is this type of arrangement guaranteed to work as a toggle, regardless of any parameters?
I am not very experienced in sequential designs, please help.

 

[FvM]

regardless of any parameters

What is "any parameter"? Sounds pretty meaningless.

To answer the question for a given logic family, look at hold time and propagation time. You'll notice that it works for any usual logic family. No relation to setup time, by the way.

A parameter that must be observed to make the T-FF work correctly is maximum clock rise- and fall time.

 

[dick_freebird]

Your setup time has to be less than clock cycle minus
CK-Q prop delay. You can pretty much count on that
delay taking care of the hold time and then some.

You could find a way to break it, but probably not before
other things in your design also fail to function. So
relax.

 

[mrinalmani]

Yes, my main doubt was regarding hold and propagation delay. At times the two were critically close, with difference not exceeding 1 or 2 nano-seconds. This tight difference was the main reason for doubts regarding the reliability. By other parameters I meant some other parameter relating to timing requirements that could be a potential cause of trouble.
Thanks for the reply.