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Article #538 (635 is last):
From: aa700@cleveland.Freenet.Edu (Michael Current)
Subject: 65816 computer
Reply-To: aa700@cleveland.Freenet.Edu (Michael Current)
Posted-By: xx004 (Atari SIG)
Date: Sun Jul 27 17:43:00 1997

From: (John Harris)
Date:  Thu, 26 Jun 1997 18:01:39 GMT

Some of you may remember an anouncement I tried to make a few years back,
but later had to keep quiet.  It concerned a new atari-compatible computer
made with a 65816 processor and some other cool stuff.  It was being
manufactured for a dedicated application that I actually never found out
what it really was.  I found out about it at a time when I was selling
character generator software on the Atari8, and having immense difficulty
obtaining Atari hardware.  It was a great connection to make, and we are
still selling these new systems with my CG software installed.

The big project never materialized, since the company making the systems
and Atari could never reach an agreement for large supply of Atari custom
chips.  It seemed like a no-brainer--Atari had chips, these guys had money,
it should have been a simple exchange.  It's no wonder Atari doesn't have
any feet left.  They keep shooting themselves there.

Anyway, the bottom line is that Atari negotiations were the reason behind
my silence at the time, and now that the project is completely dead I can
make public the details of the machine for all those that are curious.

It is based on a 5.37MHz 65816 processor, although it still runs 1.79MHz
when accessing the base 64K of address space for compatibilty with the
custom chips.  It is in a nice case with internal 3.5 high density floppy
and hard drive, parallel and serial, expansion slots, fully static memory
(turn the power off and on, and everything is still there!), mouse support,
and separate IBM-style keyboard.  It has its own Sparta-like DOS, and with
65816 optimizations the memlo gets down to $FA3.  I've found the
compatibility to be extremely good, with two main problems.  Some european
programs, especially demos, use the undocumented 6502 extra instructions,
and these don't work on the 65816 CPU.  The other issue, is that there is
no cartridge slot.  Technically, it is feasible to add a slot using a plug
in board, and run a connector out the back.  It would probably depend on
the number of interested parties for whether it was financially affordable
to get the thing made.  One nice thing about the slots though, they are
physically the same as IBM 16-bit ISA cards.  (but not electronically
compatible of course).  You can get experimenter boards for IBMs that just
run power and have all other connections open.  The do-it-yourself'er can
do pretty much anything from here.

Because of being a very low-production item, it is really expensive by
8-bit standards.  Retail is $1800 with all options and the CG software.
Obviously, it's only being sold to commercial applications like hotels and
cable TV at that price.  It is possible to make some deals if anyone is
interested, especially for systems without the CG software.  Obviously, I
need to be fair to the people who are still buying the system for
commercial use.  I don't have any prices for you, but if anyone is
interested at all, please let me know and I'll see what we can work out.
If you're just curious for info, let me know that too.

Date:  Fri, 27 Jun 1997 03:30:56 GMT

Here are some questions asked by Brent Buescher, that I'll answer here for
others to see.

-what is the video circuitry like?  which of the eight-bit models is
 it most like?  Does it incorporate Ben Poehland's Super Video fixes?

The video is engineered from scratch, and is higher bandwidth than any of
the Atari models.  It looks superb on split-video monitors.  I think it
looks very good on composite as well, but there is one factor that can make
it look worse on some monitors.  Atari's chroma signal is much too hot and
way out of NTSC specs.  Monitors will compensate for this by effectively
turning down the color gain.  What happens as a result, is that color
artifacts, the usually unwanted color fringes that occur on high res
pixels, get diminished with the reduced gain.  On the D816 (the new
system's name) the artifacts will generally be more prominant since the
color gain is higher.

There is a very simple mod consisting of a resistor soldered in parallel
across another one that brings the chroma level up to Atari XE levels, and
makes the composite output look better than XE in all cases.  There is also
a more extreme mod that requires tuning a coil, but virtually eliminates
all artifacting in the composite output.  The image is then really clean,
but you'll have to play Jawbreaker in a B/W maze as a result.  :-)

-how are the ergonomics of the DOS and hard disk system?  That is, how
 do they compare to a Black Box and Sparta?  I found the black box's
 partitioning system extremely convenient and easy to use.

He licensed the BB and Sparta software, so it is virtually identical.

-is the IBM keyboard interface featureful like the TransKey or is it

Well, it's different.  I wanted access to the function keys for my program,
so they all return unique keycodes.  Same thing with Home, End, PgUp, etc.
Some of the Shift-Ctrl letter keys that return nothing in the Atari, do
return the logically expected code on the D816.  All 256 key codes can be
returned, but there is not much in the way of 'fancy' implementation.  One
thing I like, is that the two alt keys are mapped to Select and Option,
which works out really nice when programs use Select-key combinations.  I
think some of the mappings work out to 1200XL function keys, because Home
for example takes you to the beginning of the line in any E: environment.

In short, it's a design to give additional key codes, versus additional
functionality to the existing Atari.

-does it support ultraspeed in the OS? 


-how much memory does it conveniently support?

It comes with 128K in XE compatible and ANTIC compatible banking.  At least
one board design exists to give 4 Meg (I believe) of linear addressable
memory in the 24-bit address space, but I do not have one.  My CG board has
32K of upper memory, and I believe this can be extended fairly easily to 1
meg or maybe higher.  I still need to find out all the options for memory

-how many joystick ports?

2, with standard DB9s.  It also has an Atari SIO port, but uses a DB15 so a
special cable will need to be made.  Easiest, is to chop one end of an SIO
cable and attach a DB15.

-does it support XL bank switching? (i.e. access to the full base 64K
 in the same way that XLs do) I infer from your post that it's not

It's XE-like.  Again, I'm not sure of the options to go above 128K in the
XE address space.  I know all of the portb bits are used, but I think there
is at least one bit that could be sacrificed for enhanced memory.  If
you're thinking of ramdisks though, forget it.  Access will be much faster
in upper memory because of the 5.37MHz speed when you get outside of 64K.

-- Other notes --

It has a 65816-aware OS that handles native interrupts.  The MAE assembler
supports all 65816 code and the full 24 bit address space.  There is also a
custom version for the D816 that uses the PgUp, Home, etc. keys.

John Harris             Japanese translation of Microsoft slogan:     "If you don't know where you want to go,
                         we'll make sure you get taken."
Michael Current,
8-bit Atari FAQ and Vendor Lists,
Cleveland Free-Net Atari SIG, telnet:// (go atari)
St. Paul Atari Computer Enthusiasts,

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