Interview question - Need Your opinion

[kolla]

This is an interview question I found and I'm looking for your feedback..
(There was no answer given)

Q: How do you convert transparent D-latch into rising edge D-Flop?

My initial thinking was to simply add a clock to do this.
But maybe the question is asking something deeper??

Would you guys kindly share your thinking ...

 

[gck]

A transperent D-latch already has clock as an input.
The basic difference between D-latch and D-ff is D-latch is level triggered and D-FF is edge sensitive.

So, to make rising edge D-FF, we need two Transperent D-latch, with opposite edge sensitiveness.

 

[kolla]

A transperent D-latch already has clock as an input.
The basic difference between D-latch and D-ff is D-latch is level triggered and D-FF is edge sensitive.

So, to make rising edge D-FF, we need two Transperent D-latch, with opposite edge sensitiveness.

Thanks gck for the explanation..
Would you show me how the connections should be made..
A drawing or a picture would help a lot..

Added after 55 minutes:

Actually I think I figured it out...
Looks like something like this'd work.
What do u think?

**broken link removed**

 

[gck]

Yes this connection is correct for Positive edge triggered D-FF.

 

[javatea]

You could think this question in easier way :

DFF are formed by two cascaded latches.
The first one latch is negative-level sensitive.
The second one is positive -level sensitive.
In addition, where does setup-time and hold-time come from?
For setup time, it is the amount for capturing value in the first latch.
For hold time, it is the amount for value come out in output of the second latch.

For your reference