AVR-Chat

On Thu, 2005-10-06 at 11:00 +0800, Kathy Quinlan wrote:
> Don wrote:
> > Eduardo Munoz wrote:
> >>I tried it with At76c713DK and JtagIce MkII.  
> A 48Mhz AVR now that is nice (I wonder how high our clock will go, 
> without liquid nitrogen cooling ;)

   Actually, heat isn't the limting factor.  While higher clock
frequencies will,  of course, increase heat generation, the real
problems are elsewhere.  Issues such as leakage currents which rise
dramatically as device geometries scale down for high dspeed, etc.

   If a Pentium or an Athlon can run at 3 Ghz and more without cryogenic
cooling,m an AVR can, and probably with considerably less mechanical
(e.g., fans) cooling, as well.   The real question is, what would one
reaonably *DO* with a 3 Ghz AVR?  The primnary reason that embedded
controllers run at such relatively slow clock speeds is economics.
Embedded controllers must be inexpensive.  Mutli-Ghz clocked chips are
NOT inexpensive, at any level of complexity.  Otherwise, why would wqe
all be salviating over 48 Mhz AVRs, when Intel and AMD and others
proiduce multi Ghz processors?  (hint: complexity and expense)

   Have you looked at what it takes to get a Pentium or an Athlon to do
anything useful, in terms of external support chips and circuitry (not
to mention the mechanical and cooling support required)?  Now compare
that to an AVR,m which can run completely stanbalone, withbout any
external chips at all.

   And there I go in lecture mode again.  Sowwy.

tom