Re: Hardware emulation of 6509 using 6502?

From: Mia Magnusson <mia_at_plea.se>
Date: Wed, 7 Mar 2018 17:25:24 +0100
Message-ID: <20180307172524.00003c51@plea.se>
Den Wed, 7 Mar 2018 01:18:17 +0000 (UTC) skrev Steve Gray
<sjgray@rogers.com>:
> The Max Machine uses a 6566 VIC-II chip (which uses SRAM rather than
> DRAM). Early documentation of the CBM-II series (source code) also
> mentions use of the 6566. However, released machines use the 6567,
> which leads me to believe that both were developed at almost the same
> time. The CBM-II series and the C64 are also very close, and were
> announced at the same time, unfortunately delays in the CBM-II line
> release make it seem much later. In my B-Series prototype: Commodore
> CBM-II B-Series Prototype Computer, which so far is the earliest
> known CBM-II machine, the 6509 CPU is dated 2282 (22nd week of 1982),
> the SID is 1382, and the 6526 is 0882 Steve

Maybe the 1k SRAM is a leftover from early P500 prototypes using the
6566? And then since P500's were only ever prototypes they never
bothered to remove that SRAM as the computer works which itself is a
good goal to reach for a prototype, and felt it were a better idea to
do a prototype production run with the SRAM just to get some computers
to for example software developers?

The dates of early 6566 and 6567's could probably tell something.


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Received on 2018-03-07 18:04:25

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