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From: grr@cbmvax.cbm.UUCP (George Robbins)
Newsgroups: net.micro.amiga
Subject: Re: How do I contact the SECRET 8520 DISTRIBUTION SOCIETY?
Message-ID: <752@cbmvax.cbmvax.cbm.UUCP>
Date: Fri, 19-Sep-86 02:54:01 EDT
Article-I.D.: cbmvax.752
Posted: Fri Sep 19 02:54:01 1986
Date-Received: Sat, 20-Sep-86 00:42:04 EDT
References: <6040@alice.uUCp> <13058@amdcad.UUCP>
Reply-To: grr@cbmvax.UUCP (George Robbins)
Organization: Commodore Technology, West Chester, PA
Lines: 31

In article <13058@amdcad.UUCP> tim@amdcad.UUCP (Tim Olson) writes:
>> 
>Ok.  I've seen references to an 8520, 8250, and possibly any other permutation
>of these numbers, refering to a part in the Amiga.  Not owning an Amiga, I got
>out my old copy of BYTE which reviewed it to find out what this mysterious
>chip was.  Yup, sure enough, in the margin of the board photograph was the
>text "8250" with a pointer to a pair of chips.  But wait a minute, what's this?
>MOS Technology?  Looking closer I distinctly saw the parts labeled "6520".
>Could it be?  The mysterious and unatainable 8520 is really a lil' ol' MCS6520
>(MOS Technology's second source number for Moto's MC6820) PIA? 
>
>Is there a conspiracy involving the SECRET 8520 DISTRIBUTION SOCIETY and
>Commodore to corner the market on PIAs? ;-)
>

Gee, I can never get the 8520 vs 8250 right, and I work here!  The true
facts are that an 8520 is quite unlike a 6520.  It is however, quite
similar to a 6526, but the 'time-of-day' clock is binary instead of BCD
and PC output (Centronics Strobe) has been delayed and lengthened.

For those interested, the parts numbering system used by MOS Technology,
the chip making divison of Commodore, has the first digit being a
technology code, the second being a classification and the last two digits
being arbitrary.  Thus 6526->8520 and 6510->7501->8502 and worse.

Early Amiga prototypes actually used 6526's, but all production units
use the 8520 and the software is unlikely to tolerate the older chips.
-- 
George Robbins - now working for,	uucp: {ihnp4|seismo|caip}!cbmvax!grr
but no way officially representing	arpa: cbmvax!grr@seismo.css.GOV
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)