[time-nuts] Of rubidium life and piggy-bank anemia....
magnus at rubidium.dyndns.org
Sun Dec 2 12:59:15 EST 2007
From: Bruce Griffiths <bruce.griffiths at xtra.co.nz>
Subject: Re: [time-nuts] Of rubidium life and piggy-bank anemia....
Date: Sun, 02 Dec 2007 10:56:34 +1300
Message-ID: <4751D892.5000703 at xtra.co.nz>
> Poul-Henning Kamp wrote:
> > In message <4751D4F9.4020207 at xtra.co.nz>, Bruce Griffiths writes:
> >> Poul-Henning Kamp wrote:
> >> The point is that actually using latches in this way is considered poor
> >> design practice when crossing clock domains.
> > The latches do NOT span clock domains, they are in the same domain
> > as the counter.
> > The signals that make captures the counter value in the latch is
> > synchronized to the global clock using 3 D flip-flops.
> You are missing, the point using latches latched by the output of a
> synchroniser is considered bad design practice you should use gated D
> flipflops instead.
The problem is that he calles the DFFs latches. The problem with the term
latches is that they sound like a good generic term, but really isn't.
He would not be able to synthesize the design if there where a single latch in
it. However, it is full of DFFs!
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