[Coco] Anyone else collect other old computers/game consoles beside the Coco?

[Bob Devries]

Well, I have two OS9/68k machines, and both have 68681 UARTs.

As mentioned previously, the MM/1 has a variety of available serial ports, 
and my SECAD AS-68K also has two ISA COM ports which usually use something 
like the 16450 or 8250 chip.

Regards, Bob Devries
Dalby, QLD, Australia

----- Original Message ----- 
From: "Aaron Wolfe" <aawolfe at gmail.com>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Sunday, August 28, 2011 6:24 AM
Subject: Re: [Coco] Anyone else collect other old computers/game consoles 
beside the Coco?


On Sat, Aug 27, 2011 at 12:57 PM, Joel Ewy <jcewy at swbell.net> wrote:
>
> My 68000 assembler skills are limited to having read a book, and done a 
> few
> exercises for a Computer Systems class 20 years ago or so, assembled
> ironically on a 68000 simulator that ran on an NCR Tower with a real 68000
> processor under AT&T System V UNIX. From what I gather, the DW client code
> is pretty tricky, timing-wise. Granted, a 16MHz '68K machine is a little
> faster than the CoCo, but I believe 115K+ is still outside the documented
> capabilities of the MM/1's UARTs.
>
> Speaking of which, there are a number of UARTs to choose from, not to
> mention bit-banging over one of the parallel ports. The Signetics 68070 
> has
> a serial port, which (off the top of my head) I think may ordinarily be 
> used
> for the mouse. Then there is a 68901 on the motherboard (I think) which 
> has
> another UART. The I/O board has a second 68901, and a 68681 dual UART. I
> think that makes a total of 5 possible UART serial ports. There's also an
> i2c bus interface in the 68070 which never got used for anything. I guess
> it would be useful to take a survey of the other hobbyist-oriented '68K
> machines that were out there, and see what kinds of serial interfaces they
> had. If there was any common denominator, that would be the thing to
> develop.
>
> So how would you feel about being loaned an MM/1 for a while? I'm not 
> doing
> anything with it at the moment. I would have to dig up a working SCSI hard
> drive, but if worse came to worst, one of the Macs would have to donate to 
> a
> good cause. I could probably be without the MM/1 for, say, up to a year, 
> if
> it meant a Drivewire client would come out of it. I'm more than half
> serious.
>

Wow that is a very generous offer, and tempting too.  Believe it or
not,  that is the second 68k system thats been offered on loan to me
since my last post.  Heck, if I knew it was that easy to get a MM/1
I'd have promised to write a DW client long ago...

However, when I posted that I guess I never expected to actually have
one, and now that it's a possibility I'm realizing that the time to do
this will be hard to come by, as much as I'd like to write it (and to
just have a chance to play with an actual 68k/os9 system!  I spent
many hours reading the ads and reviews in rainbow as a kid...).
It's been a long time since I wrote any code for 68k, and I've never
even seen OS9/68k.  So, the time to do the client, while it would be a
lot of fun, would be significant.

I'm not saying no, but I'd say lets wait and see where things are at
in a few months.  Maybe I'll have fulfilled some of the promises I've
made to other coco projects and feel more able to take this on.  If
someone more experienced wants to join me and help make it happen,
that might change everything :)

As for the serial hardware, I'm not familiar with the specifics of the
MM/1 but as a rule I'd say some mechanism that can handle 57,600k
would be a bare minimum for usable performance.. and that is based on
coco sized file, I suppose 68k files could be quite a bit bigger.
Darren Atkinson did an amazing job with the serial code in DriveWire
on the coco, and there is no way I could write something so nice and
precise.  However, I can make bytes go out a uart :)  So if there is
any uart type hardware that can do at very least 57,6k thats a
possibility.  115 or better would be significantly better.  As you
mentioned, it would be best to find out what hardware is common to as
wide a range of systems as possible as step one, and see what we have
to work with.

-Aaron

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