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Please Help me

Started by Joshi & Joshi ●December 10, 2009
Reply by Mike Treseler ●December 14, 20092009-12-14
Ben Jones wrote:


> I agree that it's a Very Good Idea to have a reset, but I don't see
> why it has to be an asynchronous one. By default I try to make
> everything synchronous, including resets, unless there is a strong
> case to do otherwise. I have found that this leads to fewer problems
> throughout implementation.


This is certainly a matter of style, but I like to
reserve the asynch reset for simulating power up.
I describe all other initialization, sequentially.
Like Andy said, the reset pulse has to be synchronized
in any case.

         -- Mike Treseler
Reply by Joshi ●December 16, 20092009-12-16
>On Mon, 14 Dec 2009 01:02:25 -0800 (PST), Ben Jones <benjjuk@gmail.com>

wrote:

>
>>On Dec 11, 6:07&#65533;pm, Mike Treseler <mtrese...@gmail.com> wrote:
>>
>>> True, but it simplifies simulation having a reset
>>> for the input and output registers, even if (especially if ?)
>>> the rams and some shifters don't have one.
>>
>>I agree that it's a Very Good Idea to have a reset, but I don't see
>>why it has to be an asynchronous one. By default I try to make
>>everything synchronous, including resets, unless there is a strong
>>case to do otherwise. I have found that this leads to fewer problems
>>throughout implementation.
>
>For most of the design I would agree.
>
>I confess I once had trouble with synchronous resets on clock generators, 

DCMs

>and the like. (The clock stops, so they never come out of reset.)
>
>So there are occasional roles for asynch reset...
>
>- Brian
>



Can any one Give Xct Code for this ..
it would be great help for me ..

In advance thanks ...	   
					
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Reply by Ben Jones ●December 16, 20092009-12-16
On Dec 16, 6:56=A0am, "Joshi" <Joship...@gmail.com> wrote:

> Can any one Give Xct Code for this ..
> it would be great help for me ..


I for one have no idea what "Xct Code" might be. Two people have
already posted some VHDL which improves on the original code you
posted, and others have given useful advice.

There are plenty of introductory textbooks that run through this sort
of material. If you are seeking a better understanding of digital
design for its own sake, you will find plenty of people willing to
help you here. If, on the other hand, all you want is for someone to
present you with a fully working solution to a homework problem,
there's unlikely to be much sympathy around...

        -Ben-
Reply by Andy ●December 16, 20092009-12-16
On Dec 16, 12:56=A0am, "Joshi" <Joship...@gmail.com> wrote:

> Can any one Give Xct Code for this ..
> it would be great help for me ..
>
> In advance thanks ... =A0 =A0 =A0

Joshi,

This purpose of this group is to help you to understand and use vhdl,
not to find someone else to understand and use vhdl for you (unless
you are trying to hire someone).

You have been given "xct code"  for your circuit that implements an
asynchronous reset. If you are looking for "xct code" that implements
a synchronous reset, I would suggest you google "vhdl synchronous
reset" and apply what you learn from that to the example you have
already been given.

Andy