1 Jun
2009
1 Jun
'09
12:23 p.m.
We've got a chap looking for an ID on the following - anyone got any ideas?
http://www.classiccmp.org/acornia/tmp/mystery.jpg
Photo dated May 27th 1947, apparently (so speculation so far is some form of
relay-based controller rather than a computer, but that's merely a guess)
cheers
Jules
1 Jun
1 Jun
1:50 p.m.
New subject: Interfacing a 68000 to RAM
Hi
Does anyone have a nice pointer to a diagram
of how the 68K bus is to be connected to RAM?
I not that familiar with all the various signals.
I've spent some time searching but maybe don't
have the right search string.
Dwight
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3:52 p.m.
New subject: Interfacing a 68000 to RAM
dwight elvey schrieb:
Hi
Does anyone have a nice pointer to a diagram
of how the 68K bus is to be connected to RAM?
I not that familiar with all the various signals.
I've spent some time searching but maybe don't
have the right search string.
Dwight
Google search string may be "68000 schematics", and it will point to the
first link
of "68k Single Board Comupter" from "....ac.th" which hides the
interesting part
in a CPLD, but the second link will lead to a detailed PDF
http://www.chiark.greenend.org.uk/~theom/electronics/has/ha68ksys.pdf
which describes the stuff.
Basically, you can derive the relation of UDS, LDS, R/W, AS and DTACK
from the
data sheet, for interfacing RAM the
trick part is just the generation of
DTACK;
as long as CPU clock and RAM access time is known, it is a straight forward
wait state circuit.
--
Holger
2 Jun
2 Jun
1:53 p.m.
New subject: Interfacing a 68000 to RAM
----------------------------------------
Date: Mon, 1 Jun 2009 17:52:46 +0200
From: holger.veit at iais.fraunhofer.de
To:
Subject: Re: Interfacing a 68000 to RAM
dwight elvey schrieb:
Hi
Thanks for the pointers guys. I should have given more information.
It is SRAM and it is fast SRAM 55ns. It is a real 68000 8MHz.
It seens that most seem to prefer the DTACK method over the synchronous one. Is faster or
just more versitle?
What I'm doing is to try to find the best way to connect
to my Canon Cat.
At the Information Apliances Inc they had a daughter board
that they had 128k words of RAM on (256kb).
It was used to recompile the ROM code for the Cat. My understand
is that it had a read/write address of A00000H while there
was a switch to allow it to shadow the ROM at 00H.
I don't think I need the shadow capability since I'd be happy
to just create ROM images.
I'm of course looking for a way to do this with a minimum
of cuts and hacks. I'd prefer to do this with just added
sockets and wires.
There are 2 empty 28pin locations that were intended for ROMs
that I can get most of the address and data lines from
but the parts I have are 32pin. I'll be stacking machine
pin sockets and removing the pins from the lower one
where I'll need to change or jumper to something else.
There is one CE* strobe from the ASCIs inside that I
might be able to use, so long as they didn't include
the LDS signal in its decoding. For these ROMs, they
treated them as byte sources. This ROM enable was
for extended spell checking dictionary. Doing this
has the advantage that the handshake to the CPU
is already done and doesn't require added circuit.
The disadvantage is that it is at 240000H instead
of A00000H, requiring some code change.
If this doesn't work, I'll need to hijack the address
and controls earlier. I'll need to at least cut
into either the DTACK or the VPA line to add my
own signal.
I've been ohming these lines in a powered down circuit
and it looks like they have about a 1K pulup on them
but there is no pulup resistor seen on the board,
by tracing the lines.
I can only figure it must be inside the ASIC. If
it is a O.C. line, I can just force it low without
having to cut. If it is a full pushpull, I'll need
to cut the wire.
I do have a plan for how I might also do the shadowing.
I can mount the system ROMs on machine sockets and
devert the CE* signals. It is in the same area as
the location I expect to mount the additional RAMs.
The data lines are unbuffered to the 68000 so it
should work.
First things first, get it to see the added RAM.
I should mention that we have source code for the
latest ROM version.
Dwight
_________________________________________________________________
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Hi
Does anyone have a nice pointer to a diagram
of how the 68K bus is to be connected to RAM?
I not that familiar with all the various signals.
I've spent some time searching but maybe don't
have the right search string.
Dwight
Google search string may be "68000 schematics", and it will point to the
first link
of "68k Single Board Comupter" from "....ac.th" which hides the
interesting part
in a CPLD, but the second link will lead to a detailed PDF
http://www.chiark.greenend.org.uk/~theom/electronics/has/ha68ksys.pdf
which describes the stuff.
Basically, you can derive the relation of UDS, LDS, R/W, AS and DTACK
from the
data sheet, for interfacing RAM the trick part is just the generation of
DTACK;
as long as CPU clock and RAM access time is known, it is a straight forward
wait state circuit.
--
Holger
2:18 p.m.
New subject: Interfacing a 68000 to RAM
On Tue, Jun 2, 2009 at 9:53 AM, dwight elvey <dkelvey at hotmail.com> wrote:
Hi
?Thanks for the pointers guys. I should have given more information.
It is SRAM and it is fast SRAM 55ns. It is a real 68000 8MHz.
OK... that RAM is plenty fast enough, but you also need to ensure any
memory-mapped peripheral I/O chips are also fast enough if you want to
ground DTACK. We had 4MHz 8530 UARTs, so we _had_ to use DTACK in the
"expected" way.
?It seens that most seem to prefer the DTACK method
over the synchronous one. Is faster or just more versitle?
Simple designs can ground DTACK, more complex designs tend to use
DTACK normally, especially to be able to use less expensive memory.
These days, if I were building a 68000 design, I'd look at fast memory
and fast I/O chips and just do it in the simplest way possible - when
you ground DTACK, what you are doing is telling the CPU that at the
time in the cycle that it would check (and wait on) DTACK, the
transfer has already happened (Data Transfer ACKnowledge) - the CPU
doesn't have to wait _ever_. In a mixed-speed design, if some
component is fast enough, DTACK will be grounded at that point in time
anyway, but through handshaking, not because it was permanently tied
to ground.
?What I'm doing is to try to find the best way to
connect
to my Canon Cat....
?There are 2 empty 28pin locations that were intended for ROMs
Are you trying to do ROM development? Why not use a plug-in ROM
emulator? (I like the PromICE, but it's made by someone that I've
known and worked with, starting 25 years ago, so if you have a
favorite or get one for free, by all means, use it). You don't have
to do any target-machine hacking - you get a rig that matches your
target (28-pin cables, 24-pin cables, 32-pin cables, 256Kx8, 128Kx16,
whatever) - and the PromICE is somewhat configurable in that respect -
then compile the code and download it. It could be tricky if you need
the target machine to compile your code because of the tools needed,
but you could have the Cat make the code, transfer it to another
machine via serial port or network, then keep ROM images on the other
machine so you can try new code and revert back to working code if you
compile up a dud.
I would hesitate to make recommendations on how to hack into an
existing design without schematics in front of me, but if all you are
trying to do is get writable ROMs, I'd seriously recommend a ROM
emulator that's externally loadable (built or bought, makes no
difference there).
-ethan
3:46 p.m.
New subject: Interfacing a 68000 to RAM
----------------------------------------
Date: Tue, 2 Jun 2009 10:18:33 -0400
Subject: Re: Interfacing a 68000 to RAM
From: ethan.dicks at gmail.com
To: cctalk at classiccmp.org
On Tue, Jun 2, 2009 at 9:53 AM, dwight elvey wrote:
Hi Ethan
I still need to figure how to get the 256kb of RAM into the
Cat memory.
I wasn't thinking of tying the DTACK low, just adding another
O.C. drive on the wire when decoding my new address space.
Most all of the circuits are inside of ASICs so there isn't
much other than wires to and from the CPU. Just think of
CPU, Black-Box then everything else. The Cat does use both the
DTACK and the VPA lines. I think the VPA is used for the
serial chip.
The CPU doesn't hang when accessing invalid memory so maybe
the ASIC is generating DTACKs, even for invalid memory. In
that case, all I need is address decoders.
I was thinking that the extra ROM decode might work but
thinking about proper design, they'd have put R/W in the CE*
signal. If so, I can't use it.
Dwight
_________________________________________________________________
Windows Live?: Keep your life in sync.
http://windowslive.com/explore?ocid=TXT_TAGLM_WL_BR_life_in_synch_062009
Hi
Thanks for the pointers guys. I should have given more information.
It is SRAM and it is fast SRAM 55ns. It is a real 68000 8MHz.
OK... that RAM is plenty fast enough, but you also need to ensure any
memory-mapped peripheral I/O chips are also fast enough if you want to
ground DTACK. We had 4MHz 8530 UARTs, so we _had_ to use DTACK in the
"expected" way.
It seens that most seem to prefer the DTACK
method over the synchronous one. Is faster or just more versitle?
Simple designs can ground DTACK, more complex designs tend to use
DTACK normally, especially to be able to use less expensive memory.
These days, if I were building a 68000 design, I'd look at fast memory
and fast I/O chips and just do it in the simplest way possible - when
you ground DTACK, what you are doing is telling the CPU that at the
time in the cycle that it would check (and wait on) DTACK, the
transfer has already happened (Data Transfer ACKnowledge) - the CPU
doesn't have to wait _ever_. In a mixed-speed design, if some
component is fast enough, DTACK will be grounded at that point in time
anyway, but through handshaking, not because it was permanently tied
to ground.
What I'm doing is to try to find the best way
to connect
to my Canon Cat....
There are 2 empty 28pin locations that were intended for ROMs
Are you trying to do ROM development? Why not use a plug-in ROM
emulator? (I like the PromICE, but it's made by someone that I've
known and worked with, starting 25 years ago, so if you have a
favorite or get one for free, by all means, use it). You don't have
to do any target-machine hacking - you get a rig that matches your
target (28-pin cables, 24-pin cables, 32-pin cables, 256Kx8, 128Kx16,
whatever) - and the PromICE is somewhat configurable in that respect -
then compile the code and download it. It could be tricky if you need
the target machine to compile your code because of the tools needed,
but you could have the Cat make the code, transfer it to another
machine via serial port or network, then keep ROM images on the other
machine so you can try new code and revert back to working code if you
compile up a dud.
I would hesitate to make recommendations on how to hack into an
existing design without schematics in front of me, but if all you are
trying to do is get writable ROMs, I'd seriously recommend a ROM
emulator that's externally loadable (built or bought, makes no
difference there).
-ethan 
1 Jun
1 Jun
5:55 p.m.
New subject: Interfacing a 68000 to RAM
I think I have the design manual for that processor, but I'm reorganizing my shop so
it's behind this and that.... I'll try to get to it later and if there's
anything in particular that's helpful I'll scan it for you. -- Ian
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of dwight elvey
Sent: Monday, June 01, 2009 6:51 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Interfacing a 68000 to RAM
Hi
Does anyone have a nice pointer to a diagram
of how the 68K bus is to be connected to RAM?
I not that familiar with all the various signals.
I've spent some time searching but maybe don't
have the right search string.
Dwight
_________________________________________________________________
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utorial_WhatsNew1_052009
6:11 p.m.
New subject: Interfacing a 68000 to RAM
On 1 Jun 2009 at 6:50, dwight elvey wrote:
Does anyone have a nice pointer to a diagram
of how the 68K bus is to be connected to RAM?
I not that familiar with all the various signals.
I've spent some time searching but maybe don't
have the right search string.
Download the 68K User's Manual from Freescale:
http://www.freescale.com/files/32bit/doc/ref_manual/MC68000UM.pdf
And check out Chapter 4. (It's actually very well-written)
--Chuck
7:02 p.m.
New subject: Interfacing a 68000 to RAM
On 1 Jun 2009 at 6:50, dwight elvey wrote:
You might also look at the _second edition_ of the 'Student Manual for
the Art of Electronics' (or some similar title, I can get the exact title
if you can't find it). That has a design for a 68008-based computer
(processor + SRAM + hex keypd 'front panel') which can even be built on
plugblock-type 'breadboards'. The 68000 is a very similar bus, so this
should be applicable.
IMHO this book explains things well. You don't just follow the schematic,
you understnad why you're connecting various pins to each other.
-tony
Does anyone have a nice pointer to a diagram
of how the 68K bus is to be connected to RAM?
I not that familiar with all the various signals.
I've spent some time searching but maybe don't
have the right search string.
Download the 68K User's Manual from Freescale:
http://www.freescale.com/files/32bit/doc/ref_manual/MC68000UM.pdf
And check out Chapter 4. (It's actually very well-written) 
6:59 p.m.
New subject: Interfacing a 68000 to RAM
dwight elvey wrote:
Hi
Does anyone have a nice pointer to a diagram
of how the 68K bus is to be connected to RAM?
I not that familiar with all the various signals.
I've spent some time searching but maybe don't
have the right search string.
Try something like "minimal 68000 system".
I remember having an motorola application note with this (or similar)
name. Are you trying to interface a real mc68000 or his later brothers ?
Cheers
1:59 p.m.
At 7:23 AM -0500 6/1/09, Jules Richardson wrote:
We've got a chap looking for an ID on the following
- anyone got any ideas?
http://www.classiccmp.org/acornia/tmp/mystery.jpg
Photo dated May 27th 1947, apparently (so speculation so far is some
form of relay-based controller rather than a computer, but that's
merely a guess)
My guess is something to do with trains, as that appears to be a
passenger car in the background. Is this a UK photo?
Zane
--
| Zane H. Healy | UNIX Systems Administrator |
| healyzh at aracnet.com (primary) | OpenVMS Enthusiast |
| MONK::HEALYZH (DECnet) | Classic Computer Collector |
+----------------------------------+----------------------------+
| Empire of the Petal Throne and Traveller Role Playing, |
| PDP-10 Emulation and Zane's Computer Museum. |
| http://www.aracnet.com/~healyzh/ |
2:23 p.m.
It looks like a 1940's tele-printer or fax station. Could what appears to be
a train actually be a DC3 of Northwest Airlines? If it's a train then it's
not a UK one. Wrong sort of windows and no signs that big on any UK train.
The oblong console windows seem to have some sort of printer behind them.
The square windows have what looks like paper tape punches or high speed
tape readers behind them.
Regards
Rod Smallwood
-----Original Message-----
From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org]
On Behalf Of Zane H. Healy
Sent: 01 June 2009 14:59
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Fwd: Mystery object...
At 7:23 AM -0500 6/1/09, Jules Richardson wrote:
We've got a chap looking for an ID on the following
- anyone got any ideas?
http://www.classiccmp.org/acornia/tmp/mystery.jpg
Photo dated May 27th 1947, apparently (so speculation so far is some
form of relay-based controller rather than a computer, but that's
merely a guess)
My guess is something to do with trains, as that appears to be a
passenger car in the background. Is this a UK photo?
Zane
--
| Zane H. Healy | UNIX Systems Administrator |
| healyzh at aracnet.com (primary) | OpenVMS Enthusiast |
| MONK::HEALYZH (DECnet) | Classic Computer Collector |
+----------------------------------+----------------------------+
| Empire of the Petal Throne and Traveller Role Playing, |
| PDP-10 Emulation and Zane's Computer Museum. |
| http://www.aracnet.com/~healyzh/ |
2:50 p.m.
Rod Smallwood wrote:
It looks like a 1940's tele-printer or fax
station. Could what appears to be
a train actually be a DC3 of Northwest Airlines? If it's a train then it's
not a UK one. Wrong sort of windows and no signs that big on any UK train.
You might be on to something about the Northwest Airlines; I thought it looked
more like a train carriage (sides too straight for most plane fuselages) - but
then someone over on TNMoC found a photo of a Boing 377 which is remarkably
slab-sided (and would fit date-wise).
There almost looks to be some sort of line/join across the top, just above the
'T' (which in itself is rather obscured by the foreground window) - seems a
little out of place on a streamlined plane fuselage (and therefore more in
keeping with a railway carriage), but maybe it's just paintwork.
Afraid it's unknown as to which country the photo was taken in :-(
The oblong console windows seem to have some sort of
printer behind them.
The square windows have what looks like paper tape punches or high speed
tape readers behind them.
Yes, I'm not sure if they're control logic or just some sort of I/O device
with acoustic shrouds fitted.
cheers
Jules
4:19 p.m.
Others are correct--it's a Northwest Airlines Stratocruiser. See:
http://www.ovi.ch/b377/pcs/nwa.html
This was just before they became "Northwest Orient Airlines" ("The
Proud Bird with the Golden Tail".
My guess is that since Northwest was based at Sea-Tac, that some
photos of operations from then might show similar equipment.
--Chuck
2:46 p.m.
New subject: Mystery object...
More data
The two free standing units on the left are almost certainly Teletype
Model15-RO's (Manuf. 1930 - 1954)
Regards
Rod Smallwood
I collect and restore old computer equipment with this logo.
-----Original Message-----
From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org]
On Behalf Of Jules Richardson
Sent: 01 June 2009 13:24
To: xx Classiccmp mailing list
Subject: Fwd: Mystery object...
We've got a chap looking for an ID on the following - anyone got any ideas?
http://www.classiccmp.org/acornia/tmp/mystery.jpg
Photo dated May 27th 1947, apparently (so speculation so far is some form of
relay-based controller rather than a computer, but that's merely a guess)
cheers
Jules
5:10 p.m.
We've got a chap looking for an ID on the
following - anyone got any
ideas?
http://www.classiccmp.org/acornia/tmp/mystery.jpg
Photo dated May 27th 1947, apparently (so speculation so far is some form
of
relay-based controller rather than a computer, but that's merely a guess)
My guess would be it's something for handling/sorting airline tickets.
Until recently tickets were printed on card stock with various data fields
like mag stripes, barcodes and other things. I never flew until 1988 so I
don't know what they used prior, but it was probably similar, perhaps even
regular punched cards.
--
James -
5:29 p.m.
On 1 Jun 2009 at 13:10, James Fogg wrote:
My guess would be it's something for
handling/sorting airline tickets.
Until recently tickets were printed on card stock with various data
fields like mag stripes, barcodes and other things. I never flew until
1988 so I don't know what they used prior, but it was probably
similar, perhaps even regular punched cards.
I think it's airport control. Teletype and facsimile were an
essential part of operations back then (Fax was used to print weather
maps).
My first airplane flight was on Pan Am, with meals served from a menu
on china and silverware. Flying, at one time, was something to be
looked forward to--it was almost like going on a cruise. You were
pampered.
Now, you feel fortunate to be crammed into a sardine can on a late
flight and not handcuffed and strip-searched at the terminal.
How times have changed.
--Chuck
2 Jun
2 Jun
3:49 a.m.
I don't know about tickets. I would have thought passenger lists, weather
data, cargo manifests, or dispatch documents more likely.
Regards
Rod Smallwood
-----Original Message-----
From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org]
On Behalf Of James Fogg
Sent: 01 June 2009 18:10
To: General Discussion: On-Topic Posts Only
Subject: Re: Fwd: Mystery object...
We've got a chap looking for an ID on the
following - anyone got any
ideas?
http://www.classiccmp.org/acornia/tmp/mystery.jpg
Photo dated May 27th 1947, apparently (so speculation so far is some form
of
relay-based controller rather than a computer, but that's merely a guess)
My guess would be it's something for handling/sorting airline tickets.
Until recently tickets were printed on card stock with various data fields
like mag stripes, barcodes and other things. I never flew until 1988 so I
don't know what they used prior, but it was probably similar, perhaps even
regular punched cards.
--
James -
5689
days inactive
5690
days old
20 comments
13 participants
participants (13)
-
alexandre-listas＠e-secure.com.br -
ard＠p850ug1.demon.co.uk -
cclist＠sydex.com -
dave.thearchivist＠gmail.com -
dkelvey＠hotmail.com -
emu＠e-bbes.com -
ethan.dicks＠gmail.com -
healyzh＠aracnet.com -
holger.veit＠iais.fraunhofer.de -
IanK＠vulcan.com -
james＠jdfogg.com -
jules.richardson99＠gmail.com -
rodsmallwood＠btconnect.com