Digest Number 189
1 message · 2004-07-08 → 2004-07-08 · Yahoo Group era · View archive on archive.org
Participants: Scott A. Rossell
Preserved from the Timex/Sinclair 2068 Yahoo Group (2001–2019), which is no longer online. Text reproduced from the archive.org archive; email addresses masked.
Messages
1. RE: [ts2068] Digest Number 189
Scott A. Rossell · Thu, 8 Jul 2004 06:41:
Bryan!
It was refreshing to read your personal history with the 2068. I too
miss the old days. There are some real hard core regulars here that
know just about everything you would ever want to know. As for me, I'm
just on the side lines watching with awe as they discuss their latest
project ideas. Pretty heady stuff. I'm sure they will have the answers
to your video questions.
BTW, you from the South somewhere? Comin' out with that "ya'll"? I'm a
transplanted Texan living in San Diego, California myself. My Southern
only comes out when I get mad or when the wife has the TV on the Country
Music Channel.
-----Original Message-----
From: [email] [mailto:[email]]
Sent: Thursday, July 08, 2004 1:54 AM
To: [email]
Subject: [ts2068] Digest Number 189
There are 5 messages in this issue.
Topics in this digest:
1. Highspeed Bus Expansion
From: "Jeff" <[email]>
2. Nazir Pashtoon
From: "Jack Boatwright" <[email]>
3. Re: Some Projects
From: "Jeff" <[email]>
4. Hi folks. Looks like I'm the new guy.
From: "bryankvines" <[email]>
5. ZX mirco drive interface to ts 2060
From: "Demetrius" <[email]>
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Message: 1
Date: Tue, 06 Jul 2004 19:12:08 -0000
From: "Jeff" <[email]>
Subject: Highspeed Bus Expansion
Alvin;
One way to do this would be to use a bus interface unit in an FPGA
to turn the expansion RAM into a psuedo-dual port memory. One can
certainly get memory fast enough - 20ns 512k SRAMs are available and
are not too expensive. If the DMA controller ran at 20+MHz it could
monitor the Z80 bus and do a high speed read or write to an on-chip
Z80 bus interface that would match the internal memory interface to
the Z80 bus. If the context switch happened quickly enough, the Z80
wouldn't even know it was sharing memory and would not need any wait
states. This method would lend itself to any of the forementioned
memory expansion schemes.
One of the big problems with the 2068 architecture is that writes
to video RAM can be very slow. If the TM is correct, when the SCLD
detects the Z80 attempting to access the video ram while the video
controller is active, it suspends the CPU until the next vertical
retrace period. I bring this up because while we can speed up most
aspects of the machine, anything that requires reading/updating the
screen will memory hit this bottleneck head on (unless we implement a
vertical retrace interrupt or (grin) a VGA interface...)
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Message: 2
Date: Tue, 6 Jul 2004 13:59:13 -0700
From: "Jack Boatwright" <[email]>
Subject: Nazir Pashtoon
Hi,
Does anyone know how to contact Nazir? The last email address we have
for him no is longer valid.
Thanks,
Jack
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Message: 3
Date: Tue, 06 Jul 2004 19:22:49 -0000
From: "Jeff" <[email]>
Subject: Re: Some Projects
What did you use for the expansion box?
--- In [email], "Jack" <jboatno4@o...> wrote:
> Hi All,
>
> I have posted 4 photos in the "Photos" section of this group (seemed
> appropriate :-), in a folder named "Some Projects". These depict
some
> of the stuff I've been doing the past months. T
>
> These have been shared privately with some of you. Because of the
> nice comments I've had I have decided to post for everyone's
review.
> There are more photos for each item that show the project(s) as they
> were completed, but I won't overload you all with that. ;-)
>
> Comments welcome ... and more information is available for those who
> are interested.
>
> Jack
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Message: 4
Date: Wed, 07 Jul 2004 04:16:38 -0000
From: "bryankvines" <[email]>
Subject: Hi folks. Looks like I'm the new guy.
Greetings, everybody.
I wanted to say "hi", and also that I'm glad the group is here. It's
tough finding *active*
sites or information devoted to the 2068 on the internet. Sometimes it
seems I'm about
two or three years too late -- most sites were last updated around 2000
or 2001; a lot of
links are dead; and the Internet Archive Wayback Machine is missing a
lot of information
from the dead sites.
Anyway, as an introduction, I'll tell you all a little about myself and
my TS 2068.
I got started with my 2068 back around Christmas 1984 after having had a
ZX-81 and TS -1000 for about a year before that. I stopped using my 2068
around 1985 or 1986 when I
went off to tech school. I don't remember *why* I didn't take it with me
to school, I only
remember that I didn't.
Almost all the software I had for the thing was stuff I had written
myself. I did buy Flight
Simulator and Androids. But mostly I just wrote software for it -- games
and stuff. I think I
tried writing a word processor in BASIC once, but gave up. It was too
slow. :) I never got
around to learning Z80 assembler, though I wanted to.
A friend of mine had a 2068 as well. He had a Ramex floppy drive
controller and a quad- density 5.25" drive. I eventually inherited the
Ramex board, but he kept the floppy drive.
So my 2068 went into storage as I moved on to Apple ][s and Macs.
Fast forward to about three weeks ago, when I found the FUSE (Free Unix
Spectrum
Emulator) project on SourceForge. Along with various Spectrum flavors,
it also emulates a
TC2068 which, as I understand it, is more or less the TS2068 with PAL
rather than NTSC
video.
Starting up FUSE, selecting the 2068, and seeing the twin copyright
notices at the bottom
of the screen brought on a fit of nostalgia that has so far resulted in
the rescue of my
2068 from the attic, along with the 2040 printer.
I had my Androids tape and a tape of stuff I had written in the 2068's
box, so I had to go
out and buy a cassette tape recorder. Would you believe you can't buy
one of these for less
than about $25? I would have figured they would be $5 by now, but oh
well. I got a nice
Sony from Circuit City and started cataloging my tape.
It turns out that Androids won't load anymore. R: Tape Loading Error.
Bleah. Most all of
my other software will load, though. One of the items on the tape was my
"Sci Fi" font. You
know that 60's "Computer" font? The kind the bank uses for the numbers
on the bottom of
a check? I did an entire uppercase font for the 2068 -- poked the values
in and changed
the memory pointer that controls whether to use the characters from the
ROM or
elsewhere. I also did a "Cursive" font, but I can't find that anywhere.
I guess those were the good old days, when I could spend six hours a
night for a week
working on a software project. Not having a girlfriend or much of a
social life contributed
significantly to this. :)
So anyway, I've got my 2068 set up with a 16" color TV, the 2040
printer, and my Sony
cassette tape recorder. I found a utility called "PlayTZX" that will
play a TZX file through the
sound output port of a modern desktop computer. A lot of you are
probably familiar with
it -- It's a command-line utility available for Mac OS X, Linux, and
Windows. I wrote a nice
Mac OS X GUI for it, to make it a little easier to use. As a test, I
downloaded MScript as a
.TZX file, played it out to tape, and loaded the tape on the 2068. It
worked, I was happy.
Once I get the documentation written, I may post it in the Files section
if anybody is
interested.
Okay, I'll stop typing now and let you get back to whatever it was you
were doing. I've got
a few questions about TS2068 video, but I'll wait a few days before I
post them.
Thanks for being here, y'all!
--
Bryan K. Vines
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Message: 5
Date: Wed, 07 Jul 2004 09:23:30 -0000
From: "Demetrius" <[email]>
Subject: ZX mirco drive interface to ts 2060
Hi All
I need some help with interface ZX Mircodrive to TS 2068
So anyone who can help please do
[email]
[email]
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