State machine design doubt

[vivek_p]

I have read in many papers that while designing an FSM we have to separate the combinatorial logic and sequential logic(registering to flops)...............

(ie we have to use 2 always block - one for combinatorial and other for sequential)

Why is it so?

 

[DigitalLogician]

Here is a good article with many interactive circuits: **broken link removed**. This sounds like what you are looking for.

Here is a quote from the article:

"...all sequential circuits inevitably comprise flipflops and latches; otherwise sequencers could not store information. And since the set of flipflops and latches is very small (i.e. RS, D, JK, T), we could as well pick which flipflops we wish to use from the outset and design around that type of flipflop."

Good luck

 

[skyfaye]

It makes the code more readable.

- Hung

 

[DigitalLogician]

Designing for Testability

In a nutshell, it has to do with "Designing for Testability." Combinational circuits and sequential circuits are not tested the same way. So by separating the two sections, you build your circuit with testability in mind.

So in addition to looking at the article I pointed you to (**broken link removed**), you should do additional research on "Designing for Testability."

 

[kamalkundu]

It increases the verification easy and also that is easy to modify if needed on further stages.

 

[k12345k12345]

See Clifford Cummings 2002 paper presented @ ICU for further details.