please see remarks embedded below.
Dick
----- Original Message -----
From: ajp166 <ajp166_at_bellatlantic.net>
To: <classiccmp_at_classiccmp.org>
Sent: Friday, November 03, 2000 4:59 PM
Subject: Re: Monitor for iSBC 8024
> From: Richard Erlacher <richard_at_idcomm.com>
>
>
> >The Z80 core is about three times the size of the 650x core and really
> can't
> >do anything the 650x core can't do quite a bit faster. If you clock the
> two
>
> That may be true, I don't care. It's a "but, who cares" thing. If a
> manufacturer used z80 in a product and wanted an improved product
> do you think they will drop z80 or find a way to to package it tighter.
>
Since cores were not germane to the topic at hand, you're right. However,
if a manufacturer uses a Z80 and wants more performance, the thing's still
made, so all he has to do is buy higher performance devices and adjust
whatever timing parameters are involved. If he designs a new product with
the thing, however, he gets what he deserves. That goes for using any CPU
rather than an MCU.
>
> >Gate arrays are not relevant to the typical microcontroller application.
> >The gate arrays are handy when an MCU is not fast enough, but for short
> >runs, where the MCU's shine, the FPGA's and CPLD's are much slower to
> >develop.
$100K is a bout the minimal cost for a gate array application. An MCU
application doesn't require that sort of up-front outlay in general. FPGA's
are in between somewhere, but higher than the MCU's. That's why several
vendors have core+ products now. You design the FPGA around the core in an
array including whatever memory and peripheral functions are required. That
makes sense on the way to a full ASIC design, in the event volume warrants
it. It's not like the '80's any more. If your product is profitable enough
to be worthy of any sort of volume production, someone else will steal it if
you don't use the most cost-effective production methods. Therefore, you
don't waste money on MPU's if an MCU will do the job for less cost.
>
>
> You only have worked with low volume stuff then. In the high volume
> world it's common for vendors to suff parts into ASICs as a cost
> reduction
> or product design protection.
>
You're onto something there, Allison, I normally work the first few monents
of the product design cycle, i.e. from concept to first functional
prototype. I've seldom worked on the final "productized" version, though I
frequently see "fixes" or upgrades on the way to a new product version.
However, that's not what the topic is.
>
> >The single-chip examples I think about when I'm considering what to use
> are
> >frequently the Scenix SX family. They're as fast as a core in an FPGA,
> and,
>
> Who cares. I didnt' exclusivly say speed was the issue. You did.
>
Speed isn't the point behind using the SX. The SX will accomplish what a
gate array would do in a large-volume application, though its cost is in the
low-volume range, i.e. the parts are cheap regardless of your volume,
because they're already high-volume products before you buy them. The speed
is what allows you to implement complex functions with the relatively
inexpensive part at speeds achievable only with gate arrays. That puts the
mcy in the role of a logic element. If you code it to behave as an 8255,
then that's what it is. The same component could function as a USART or
some other "LSI."
>
> Allison
>
>
Received on Fri Nov 03 2000 - 20:20:30 GMT