This winter I'd like to try and build the RE Robot
Brain board (80188) that appeared in Radio Electronics
contemporary with the 68k articles. I have on hand an
approximately 4' x 2.5' sheet of double clad circuit
material, and I could cut the size I needed from that.
But it got me to thinking (uh oh). Wouldn't it be fun
to build a REALLY big motherboard. You could put all
sorts of uP's on it, ala the Dimension 68000. You
could put the kitchen sink on it (literally). More
then likely you could build something so powerful, you
could throw out your Terragigahertz Pentium whatever
system, and heat your home at the same time. And
probably the surrounding neighbors home's too. You
might even cripple the power grid. It would be like
sort of a black hole for electrons. Has anyone built a
really big motherboard?
__________________________________
Yahoo! FareChase: Search multiple travel sites in one click.
http://farechase.yahoo.com
>
>Subject: RE: DEC "Junk" rescued
> From: Paul Koning <pkoning at equallogic.com>
> Date: Wed, 16 Nov 2005 09:33:03 -0500
> To: cctalk at classiccmp.org
>
>>>>>> "Allison" == Allison <ajp166 at bellatlantic.net> writes:
>
> Allison> I thought the 11/24 was the 11/23 chipset (F-11) mated to
> Allison> Unibus rather than the Qbus.
>
>Correct.
>
> >> 11/24 is split I&D UNIBUS, right?
>
>Nope...
>
> paul
Funny thing about PDP-11 system models. Even number for the most part
are unibus like 11/34 or 11/44 (11/05, 11/35 exception) and odd number
like 11/03, 11/23 are qbus.
I&D for Chipset CPUs didn't start untill the J-11. The F11 gave us
user/system register sets and the MMU. The unibus J11 was the 11/84
I believe.
F11 machines are a good workhorse 11s. As far as my data goes all of
the chip (F11 and J11) cpus on unibus are faster by some amount as
there isn't the multiplxed address/data bus transaction. Though I
believe the real reason was to preserve the unibus IO investment
and generally higher IO transaction rate that unibus devices enjoyed.
Allison
Allison wrote:
> Everyone has done the PC emulating whatever. Why not take a
> single chip micro and use that to emulate another micro as
> hardware? Same idea maybe slow but for a lot of things speed
> is not the whole world.
> I did it on paper for PDP8 and it was possible using an 11mhz
> 8049 to come within 1/10 the speed of a real 8. I guess a
> 36bit machine could be done as well (though really slow.).
> Also a front pannel could be programmed into it as well
> (maybe a speed hit). Any cpu that gets an instruction from
> memory and then executes it can be emulated that way.
1/10 the speed of a real PDP8? Really? That is fast indeed!
My emulation of a PDP8, running on a 68B09 (at 2 MHz) gets to
approx 1/60 of the real thing. I measured that by running some
diagnostics. The diag says "bell rings after approx 5 seconds),
and timed how long it took on my 68B09...
I am sure that when I remove the front panel code things run
faster. The front panel requires time to update. But running
the emulation without the front panel is no fun.
- Henk, PA8PDP.
This message and attachment(s) are intended solely for the use of the addressee and may contain information that is privileged, confidential or otherwise exempt from disclosure under applicable law.
If you are not the intended recipient or agent thereof responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution, or copying of this communication is strictly prohibited.
If you have received this communication in error, please notify the sender immediately by telephone and with a "reply" message.
Thank you for your cooperation.
>
>Subject: Re: homebrew 'puter project (was: 8008?
> From: "Chuck Guzis" <cclist at sydex.com>
> Date: Wed, 16 Nov 2005 12:13:15 -0800
> To: cctalk at classiccmp.org
>
>On 11/16/2005 at 1:34 PM Allison wrote:
>
>
>>Unless it gets crazy I tend to do that. Create a parallel interface with
>>a protocal to talk over it to a slave and let the slave do the grunt work.
>>Did that back around 81 for the first time using 8085 and 8035 and found
>>it nice to have a limited IO on the host yet get good performance. Now
>>with AVR, PIC and others it's pretty reasonable. Just let it interrupt
>>the host when there's something for it or when done.
>
>Of course, since a PC has all of the I/O support needed, one could simply
>let it be the I/O servicer.
>
>That way, if a problem with the homebrew box came up, the homebrew hardware
>could be emulated on the PC. One could even cut down on construction and
>debugging time by simply sticking the necessary components into a
>prototyping PCB, skipping the nasty wiring stage just adding an illuminated
>LED on the board (blink if you want) and emulate the whole lashup on the
>PC.
>
>Sort of like sitting behind the wheel of a car with the engine turned off,
>saying "vroom, vrooooom".
>
>:)
>
>--Chuck
;)
I reject that for only one reason. The PC is too big and power hungry.
I'm up for gutting an old laptop and using the battery, keyboard and
display. Oh and the hinge. :)
Allison
I made my own ribbon cable, removed the drive's input connector
and hooked everything up (making sure all the A pins of the Berg
connectors aligned with the stripe). Crossed my fingers and
powered up the system. Guess what... same error, Fault and Ready
lamps lit again, Load lamp out. Crap!
But all was not lost. Once again I checked for system clock and it
was not on the correct pins any more. I counted from each end of
the header cable (attached to the drive board connector) and
noticed the clock signals were on the 13th and 14th pin from the
end. That's M and N at the drive logic board end, confirmed by the
schematic, but the clock is on pins HH and JJ at the RL8A end
which just happens to be the 13th and 14th pin from the other end!
So - although the 40 pin cable is a "straight through" (pin for
pin), it turns out one end has to be reversed I flipped the Berg
connector over at the RL8A and everything now works :) It is
definitely inverted though, the black stripe on the ribbon cable
is in the "wrong" place for the RL8A end now.
I let it spin with the heads locked out for a while to remove all
the dust I probably stirred up. It operateds without any funny
noises (can't even hear it over the 8/A fans) and the Ready lamp
now lights after pushing the Load button and waiting for spin-up,
which is proper behavior. Then I keyed in the 10-word get-status
program from the manual and it returned the proper status words
(head over track 0, no error bits set) and can tell if the cover's
open, the write protect switch is pushed, etc.
Now all I need is software :)
-Charles
Yep, Roger, I know! I have the 6309 here, and guess where I bought it :-)
AFAIK Cloud 9 is the only source. There will probably be others that sell
this chip, but Cloud 9 is the only source I know of. I never bother with the
chip selling sites that want your (e-mail) information, you say what you want,
and they will give you a quote ... yeah, but I only want *one* not 1000!
The downside of the 6309 is just what you say: to squeeze speed out of it,
you must go into native mode. Many 4-cycle instructions execute in 3 cycles,
so roughly you gain approx. 25%. You pay that by an expensive chip, and
to make full use of the native mode, you must drop 6809 code, or write it
in conditional assembly. I will use the 6309 instead of the 68E09 one day!
Given the time, I enjoy writing the 68000 code from the 6809 so one day
I might start this project. It is pure software to me, because as I said, I have
built a 68000 modular system 10 year ago. It is still in the attick ...
- Henk, PA8PDP.
________________________________
Van: cctalk-bounces at classiccmp.org namens Roger Merchberger
Verzonden: wo 16-11-2005 20:18
Aan: General Discussion: On-Topic and Off-Topic Posts
Onderwerp: RE: homebrew 'puter project
Rumor has it that Gooijen, Henk may have mentioned these words:
>... and to put oil on the fire, I am thinking about redoing the 6809 part,
>and replace it by a 68000 at 10 MHz. Maybe a single board with just
>enough I/O ports (not PIT 68230 IIRC, but simple octal latches) for
>the pdp8/e console and RAM plus EPROM on board.
>But as said: I am *thinking* about it.
>I probably first start figuring out if rewriting the pdp8/e emulator 6809
>code into 68000 assembler, making use of all the registers will give
>the speed increase to compete with the real pdp8/e.
>I have my doubts.
If you wanted to do something to make it go faster but not cause you to
rewrite everything, you could replace the Moto6809 with a Hitachi 6309 -
code / clock / pin compatible with the 6809, but if you set it to
"non-compatible mode," has access to extra registers, fewer cycles for most
instructions, not to mention a hardware divide & some 32-bit math instructions.
It'll also clock at 3 to 4 Mhz (for the CMOS part - the 63C09) so you could
see quite a speed increase for not a lot of work...
One downfall: they ain't cheap (altho cheaper than an 8008! ;-) and can be
tough to find if you don't know where to look. I do, tho. ;-)
Browze on over to http://www.cloud9tech.com/ - they keep 'em in stock
there, $31 each. Great guys, and are still supporting the CoCo!
Laterz,
Roger "Merch" Merchberger
--
Roger "Merch" Merchberger | Anarchy doesn't scale well. -- Me
zmerch at 30below.com. |
SysAdmin, Iceberg Computers
This message and attachment(s) are intended solely for the use of the addressee and may contain information that is privileged, confidential or otherwise exempt from disclosure under applicable law.
If you are not the intended recipient or agent thereof responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution, or copying of this communication is strictly prohibited.
If you have received this communication in error, please notify the sender immediately by telephone and with a "reply" message.
Thank you for your cooperation.
>
>Subject: Re: homebrew 'puter project (was: 8008?
> From: "Chuck Guzis" <cclist at sydex.com>
> Date: Wed, 16 Nov 2005 10:14:12 -0800
> To: cctalk at classiccmp.org
>
>If I were to build a system from chips today, I'd probably relegate all of
>my I/O devices to some commodity interface, using single-chip
>microcontrollers where some particular intelligence was required. Leave
>the CPU free for the heavy computational lifting.
>
>Cheers,
>Chuck
Unless it gets crzy I tend to do that. Create a parallel interface with
a protocal to talk over it to a slave and let the slave do the grunt work.
Did that back around 81 for the first time using 8085 and 8035 and found
it nice to have a limited IO on the host yet get good performance. Now
with AVR, PIC and others it's pretty reasonable. Just let it interrupt
the host when there's something for it or when done.
Allison
I found (a) problem, probably (the) problem, after several hours
of board-level debugging trying to figure out the Fault
indicator... the fancy original DEC ribbon cable is bad at the
Berg end where it plugs into the controller!
With the board in the card extender, which is the only way to
allow the cable to move and reproduce the problem, I flexed the
ribbon cable to about 45 degrees above the board. Lo and behold...
the Fault lamp went out :)
I am now making a Berg-Berg cable and will install it from inside
the drive compartment. This will obviously help but I'll post when
(if) it's running. ;)
Interesting that this same discussion is taking place on cctalk
with someone else's "new" RL02...
-Charles
