Help to identify this RAMBoard (An update)...

16 views
Skip to first unread message

Rodolfo Leal

unread,
Feb 6, 2004, 10:53:46 AM2/6/04
to
Hello everybody,
Well, first at all, I want to thank to Kevin and Robert Bernardo
for their help. It seems that the RAMBoard that I have is a curious
beast, to say the least.
I made a couple of pictures of the board (up & down). Hope they
ring the bell and finally I can know out how to connect it.
The first picture is at the following address:

http://www.geocities.com/cpu_loyal/files/RAMBoardUP.gif

The small IC is a 74139 and the big one is a IMS2630P (or a
D2187A-25 on Kevin's 1541 RAMBoard). The socket has 28 pins. Please
note the pads labeled A, B & C.

The second picture is at the following address:

http://www.geocities.com/cpu_loyal/files/RAMBoardDW.gif

The picture tries to show the traces side. Socket's pin 27 is
missing by design.
OK, let's give another chance to this board. Meanwhile, I already
got the parts to build my own, using a 32KB chip. Let's see what
happens.

Regards,
Rodolfo Leal

Wolfgang Moser

unread,
Feb 8, 2004, 6:43:23 AM2/8/04
to
Hello Rudolfo,

> http://www.geocities.com/cpu_loyal/files/RAMBoardUP.gif
> http://www.geocities.com/cpu_loyal/files/RAMBoardDW.gif

I followed the original thread, but because I never owned
such a thing and never saw one, I wasn't able to clear out
some things.

I follow the opinion of others, that this board is probably
made for the 1571 floppy disk drive. Mainly because I can
see this 28pin adapter socket pins. The problems is, that
this board got a too high profile for the 1571, although
the adapter pins are soldered directly into the board
(there's no adapter socket used).

I suspect, that this board could probably used within the
1541-II or the 1541C disk drive. Both contain 28pin EPROMs
that carry the most important data signals D0..D7 and
A0..A12. It's pointless, if these bus signals are taken
from the main processor (40 pin socket) of some of the ROM
chips.


The diffiicult part is the adress decoding logic and the
signals, that are additionally required to drive the /CS
signal.

According to
http://www.lb.shuttle.de/puffin/8k1541/8k-expansion.gif
the decoder must not only enable the added RAM in the right
address space (e.g. $6000...$8000), but it must also ensure,
the internal adress space usings are disabled.

E.g. within the 1571 disk drive all the address space from
$4000 to $8000 is used by the CIA (although only 16 bytes
would be needed).


The main interestiing part of your board is the 74LS139
decoder chip. You should go on with creating a little
schematic of all of the connections, with that chip.
Interpreting such a schematic, it could be easier for
some people to find out, onto which lines the three wires
have to be connected.

For sure, one of the lines should be connected to the
RAM-/WE signal of the main drive board (this line is
surely connected to /WE of the RAM chip of your board).


Womo

--
------ to obtain more infos about me, look up the page ------
---- http://www.wmsr.de pwnah (at) d81 (dot) de ----

path0s

unread,
Feb 9, 2004, 12:34:42 AM2/9/04
to
I can say that the pics of the board you have is NOT the RAMBOard 1571. I
have one. The 1571 version has 2 PCB's joined by a small ribbon cable. Both
PCBs have long soldertailed pins on the chip sockets that plug directly into
the empty sockets on the 1571. You then put the chips that you took out to
create the empty sockets on the 71 into the sockets on the RAMBOard.

I don't see any long pins on those sockets in the pics, which is odd for a
RAMBOard. As you noted, there is the A,B,C lines, and I see a couple of
other pads that could be used for external wiring.

I've seen the 1541 version as well, and this doesn't look that board either.
My guess is that this could be for one of the built in drives. Such as on
the 128D or the SX64.

Unfortunately, I don't really have an answer to your question. Only that you
can eliminate it being for the 1571.

-P

"Rodolfo Leal" <cpul...@uymail.com> wrote in message
news:d8d8fcb5.04020...@posting.google.com...

Rodolfo Leal

unread,
Feb 9, 2004, 4:48:35 PM2/9/04
to
OK,
I cleaned up the schematics that I made, following the traces with
an ohmeter. It's on the following address:

http://www.geocities.com/cpu_loyal/files/RAMBoardSCH.jpg

To avoid cluttering the drawing, I numbered most of the pin
connections. I used the 6264 chip to label the RAM pins, because I
didn't find a data sheet for the IMS2630P or the D2187A. The image has
a size of 800 KB.

Regards,
Rodolfo Leal


"path0s" <pat...@c64.org> wrote in message news:<UZEVb.6406$5M.1...@dfw-read.news.verio.net>...

path0s

unread,
Feb 9, 2004, 5:40:16 PM2/9/04
to
So just to clarify, does the socket or chip on the ramboard have really long
tails on the underneath of the board? Like long enough to plug into another
ic socket if the ramboard was sitting on top of another PCB?

-P

"Rodolfo Leal" <cpul...@uymail.com> wrote in message
news:d8d8fcb5.04020...@posting.google.com...

Rodolfo Leal

unread,
Feb 9, 2004, 9:15:55 PM2/9/04
to
"path0s" <pat...@this.email.dont.wo.rk> wrote in message news:<p%TVb.6431$5M.2...@dfw-read.news.verio.net>...

> So just to clarify, does the socket or chip on the ramboard have really long
> tails on the underneath of the board? Like long enough to plug into another
> ic socket if the ramboard was sitting on top of another PCB?

Yes it does. The socket has pins going underneath the board. Here's
where the pin 27 is missing, and there's no evidence of being broken
or anything like that.
By the way, on the schematics I drawed a capacitor connecting pins
8 and 11 of the 74139. I don't know if it really is such component,
because there are no additional marks on it. It's the red thing on the
picture.

Regards,
Rodolfo Leal

Wolfgang Moser

unread,
Feb 10, 2004, 5:29:32 PM2/10/04
to
Rudolfo,

Rodolfo Leal wrote:


> path0s wrote:
>
>>So just to clarify, does the socket or chip on the ramboard have really long
>>tails on the underneath of the board? Like long enough to plug into another
>>ic socket if the ramboard was sitting on top of another PCB?
>
> Yes it does. The socket has pins going underneath the board. Here's
> where the pin 27 is missing, and there's no evidence of being broken
> or anything like that.
> By the way, on the schematics I drawed a capacitor connecting pins
> 8 and 11 of the 74139. I don't know if it really is such component,
> because there are no additional marks on it. It's the red thing on the
> picture.

I myself tried to create a schematic from yours wiith Eagle.
You may have a look at: http://d81.de/shared/RAMBoard-003.gif

Since most of your drawed connections of the 74LS139 gave me
a big headache (some outputs of this IC cannot be connected
to other output pins), I mostly tried to recover the lines
from the earliier (bad) JPEG photos.

One example for a connection, that cannot be:
You drawed one end of the capacitor to pin 8 of the LS139,
which is this' IC ground connection (GND). The other end of
the capacitor connectets to GND of the RAM and socket.

From what I can see from the photos, pin 8 of the LS139 and
all the other GNDs from the RAM, ROM and socket are connected
to one single trace, which again is connected to one end of
the capaciitor. So the question is: Where's the other end of
the capacitor really connected to? In my opinion, it should
be Vcc (+5V), but this again wouldn't make sense, since then
the RAM-/OE will never become active... ???

Maybe you are able to put your RAMBoard onto your scanner,
so that maybe some higher quality pictures may be available?

And perhaps you want to remeasure each pin of the LS139, to
become absolutely sure about your schematic. I believe, that
you interchanged some of the numberings of the LS139 (I know,
what I'm talking of, since I did a similar job 2 years ago
with a slightly bigger speeder board).
It would be good, if you would also remeasure pin 20 from
the RAM chip and pin 22 from the socket adaptor as well
as pin 22 of the ROM socket.
The four pads in the upper right/left corner directly beside
the capacitor are also puzzling me, I can't see, which one
are connected together and which aren't.


All of the lines of the LS139 must be identified 100%
until I perhaps get a chance to guess, how the wires A,
B and C must be connected to (B is already perfectly
identified as you can see).

path0s

unread,
Feb 10, 2004, 8:13:44 PM2/10/04
to
I'm not totally sure that the A B and C lines need to be connected to
anything.

On the RABOard 1571, there's 4 header pins that are for some type of
accessory. They don't need to be connected to anything for the board to
work. I believe they may be used to connect RAMBOards together on 2
different drives.

One thing that has me wondering is the designation 2C after the word
RAMBOard on this particular PCB.. On the 1541 and 1571 boards I've seen,
they say "RAMBOard 1541" and "RAMBOard 1571".. I haven't been able to come
up with a commodore drive that could be described by the term "2C".

Does anyone know if CLD made any accessories for the Atari, Apple, Amiga, or
any other type computer? Are we totally positive that this is for a
Commodore drive?

-P

"Wolfgang Moser" <pw...@d81.de.invalid> wrote in message
news:c0bm0c$lti$1...@online.de...

Wolfgang Moser

unread,
Feb 11, 2004, 3:37:55 AM2/11/04
to
Hi path0s,

> I'm not totally sure that the A B and C lines need to be connected to
> anything.

> [...]


> One thing that has me wondering is the designation 2C after the word
> RAMBOard on this particular PCB.. On the 1541 and 1571 boards I've seen,
> they say "RAMBOard 1541" and "RAMBOard 1571".. I haven't been able to come
> up with a commodore drive that could be described by the term "2C".

There's the Commodore 1541-II (2) and the 1541C (C). Because
the RAM-/WE line is built with a PLA chip on these drives,
they do have some similarities. And because both these drives
use a 28pin DOS ROM 27128 EPROM (OTP) chip, this RAMBoard may
be built exactly for these driive types.

But we can only be sure, when we know the connections of the
LS139.

As I can see by the many option bridges of that board, it may
be configurable to other drive types.

path0s

unread,
Feb 11, 2004, 3:48:55 AM2/11/04
to
I suppose it's possible, I guess I was figuring they would've used something
like "II/C" or similar to describe it. Who knows though? :) I'll have to
pop the tops on my II and my C to see if a board that shape and size would
clear the other components in both drives when installed.

-P

"Wolfgang Moser" <pw...@d81.de.invalid> wrote in message

news:c0cpl3$dls$1...@online.de...

Wolfgang Moser

unread,
Feb 11, 2004, 4:34:23 PM2/11/04
to
Hello group thread,

some more hopefully educated guesses to the schematic
I started yesterday and here's a draft version of a
redesigned RAMBoard-2/C.

Most probably the A connection pad must be connected
to the A14 address line, the B pad to RAM-/WE. The
C pad seems to be a general RAM-Enable pin, that should
be connected to a switch.

I assume, that the RAM is enabled within the
$8000..$9FFF address space. The ROM must be enabled
within $C000..$FFFF, because the Kernal of the 1541
is assembled for exactly that space.

Currently I don't know and haven't any hints, how the
/CS1 line of the RAM is connected.


Find some updated schematics at:
http://d81.de/shared/CLD-RAMBoard-007.pdf (273KB)
http://d81.de/shared/RAMBoard-sch007.png (40KB)
http://d81.de/shared/RAMBoard-brd007.png (19KB)

Rodolfo Leal

unread,
Feb 11, 2004, 10:59:02 PM2/11/04
to
Wolfgang Moser <pw...@d81.de.invalid> wrote in message news:<c0bm0c$lti$1...@online.de>...

> Maybe you are able to put your RAMBoard onto your scanner,
> so that maybe some higher quality pictures may be available?

I did as you asked for. I updated the pictures with another scanned
with better resolution. The links are the same.

http://www.geocities.com/cpu_loyal/files/RAMBoardUP.gif
http://www.geocities.com/cpu_loyal/files/RAMBoardDW.gif

If for some reason you get a page not found message, use the following
link:

http://www.geocities.com/cpu_loyal/files/ramboard.html

Let me know if these are more useful.

> And perhaps you want to remeasure each pin of the LS139, to
> become absolutely sure about your schematic.

OK, I checked again. You were right, I made a few mistakes. Here's the
list of the 74LS139 pins and where are they connected.

Pin 1 - Pin 22 of socket lower extension
Pin 2 - Pad A
Pin 3 - Pin 8 of 74LS139 and to one extreme of the capacitor (red
thing)
Pin 4 - Pin 15 of 74LS139
Pin 5 - Pin 22 of socket upper side
Pin 6 - NC
Pin 7 - NC
Pin 8 - Pin 3 of 74LS139 and to one extreme of the capacitor (red
thing)
Pin 9 - NC
Pin 10 - NC
Pin 11 - Pin 22 of SRAM chip an to the other extrem of the capacitor
(red thing)
Pin 12 - NC
Pin 13 - Pin 26 of socket (both upper and lower side)
Pin 14 - Pin 1 & 26 of SRAM chip and C pad
Pin 15 - Pin 4 of 74LS139
Pin 16 - Pin 28 of SRAM chip, pin 27 & 28 of socket (though pin 27 is
missing in the lower side)

> It would be good, if you would also remeasure pin 20 from
> the RAM chip

Pin 20 of SRAM chip is not connected to anything or to pin 20 of
socket.

> and pin 22 from the socket adaptor as well as pin 22 of the ROM socket.

The socket side and the solder side (upper and lower side) are not
connected, i.e. if a ROM chip is connected at the socket, the board
will not feed the signal.

> The four pads in the upper right/left corner directly beside
> the capacitor are also puzzling me, I can't see, which one
> are connected together and which aren't.

Hope the new picture and my description gives you a better idea.


Regards,
Rodolfo Leal

Wolfgang Moser

unread,
Feb 12, 2004, 5:28:52 PM2/12/04
to
Hello Rudolfo,

>>Maybe you are able to put your RAMBoard onto your scanner,
>

> I did as you asked for. I updated the pictures with another scanned
> with better resolution. The links are the same.

Wonderful, now I can really see some of the previously
unknown traces as well as connections, that weren't
made really.

>>And perhaps you want to remeasure each pin of the LS139, to
>

> OK, I checked again. You were right, I made a few mistakes. Here's the
> list of the 74LS139 pins and where are they connected.

Thanks, this made me sure of most of my assumptions.

Updated versions of the schematic and board can now be
found at:
http://d81.de/shared/RAMBoard/

>>It would be good, if you would also remeasure pin 20 from
>>the RAM chip
>
> Pin 20 of SRAM chip is not connected to anything or to pin 20 of
> socket.

But it must be, otherwise the RAM will never be enabled.
Maybe the IMS2630P is a special chip without a /CS
(or /CE or /G) line, but I can't believe that. Other chips
from Inmos, that I found in an old memory chips book,
always carry such a Chip-Enable line.

I got an idea: Please check out, if the RAM pins 20 (/CS1)
and 22 (/OE) are connected to each other, this is an often
used technique known from other Commdore extensions.

>>The four pads in the upper right/left corner directly beside
>>the capacitor are also puzzling me, I can't see, which one
>>are connected together and which aren't.
>
> Hope the new picture and my description gives you a better idea.

It did, but there's one open isse beside the RAM pin 20.

Please look onto the jumper described with the numbers
1, 2 and 3:
Where is Pad 3 connected to? This connection is
unvisible half the way.

Pad 1 is connected to Pin 4 of the LS139. I assume, that
Pad 2 is connected to Pin 15 since the jumper pads 1 and 2
are connected and you reported that pin 4 and 15 of the
LS139 are connected altogether. But you could make the
proof, that Pad 1 and 2 are really conncted to Pin 4 and 15
of the LS139.


If the RAM-/CE signal (pin 20 of the RAM) is not connected
to anything else, your RAMBOard may not work. If the RAM chip
doesn't care of this signal, then I propose the following as
described in the schematic:

Connect pad/cable A to address line A14 somewhere on
the board of a 1541C or a 1541-II disk drive.

Connect pad/cable B to the RAM-/WE signal of the RAM
chip, that is mounted to the drive board.

Connect pad/cable C either to +5V (high level), which
can be found on another pad of the RAMBOard (look onto
my redrawed schematic) or to a little switch, that
selects +5V or GND.

Get out the 28 pin. ROM chip out of the drive's socket,
plug it into the free socket of the RAMBOard and the
RAMBOard into the now empty socket of the 1541C/-II
disk drive.

(have a look at funet.fi to find points to connect the
cables to:

http://www.funet.fi/pub/cbm/schematics/drives/new/1541/1541-II.340503.gif
http://www.funet.fi/pub/cbm/schematics/drives/new/1541/tech/1541-33b-right.gif
maybe A14 can be get from the 6502 processor, R/W either
directly from the 2016 RAM chip or the gate arrays)


Maybe the real use of pad/cable C is, that the RAM chip
can be enabled or disabled by uploaded programs withing the
1541. Then this line most probably has to be connected to
a free VIA port line.
Maybe other readers/writers of this thread are able to
compare their versions of a RAMBOard and especially their
documentation about this issue.

Is anyone willing to scan in the manuals (for me german
manuals are also welcome :-) of their RAMBOard hardware?


Some remarks onto the memory layout of such a RAMBOard
equipped drive. As I know from other versions/revisions,
the additional 8K RAM is normally installed at the memory
lkocations $6000..$8000. With the revision 2/C the address
decoding puts the 8K RAM into the region $8000..$A000.

This may not be very compatible to some copy programs,
where the RAM chip location cannot be configured freely.
Especially this address decoding is not compatible to the
1571 disk drive, because it uses a 32K ROM which is laid
into the adress space $8000..$FFFF. This definetly proofs,
that this version of the RAMBOard wasn't designed for the
1571 disk drive.


Are there any questions remaining?

Rodolfo Leal

unread,
Feb 12, 2004, 11:17:28 PM2/12/04
to
Wolfgang Moser <pw...@d81.de.invalid> wrote in message news:<c0gun3$pb2$1...@online.de>...

> I got an idea: Please check out, if the RAM pins 20 (/CS1)
> and 22 (/OE) are connected to each other, this is an often
> used technique known from other Commdore extensions.

Wow! I knew I came to the right place. You're absolutely correct. I
was sure that I traced all the pins, but missed this. Pins 20 and 22
of the RAM chip are connected togheter. I missed it, because I was
expecting a trace going to the socket.

> Please look onto the jumper described with the numbers
> 1, 2 and 3:
> Where is Pad 3 connected to? This connection is
> unvisible half the way.

Pad 3 is conected to pin 16 of the LS139

> Pad 1 is connected to Pin 4 of the LS139. I assume, that
> Pad 2 is connected to Pin 15 since the jumper pads 1 and 2
> are connected and you reported that pin 4 and 15 of the
> LS139 are connected altogether. But you could make the
> proof, that Pad 1 and 2 are really conncted to Pin 4 and 15
> of the LS139.

I knew I missed to trace these pads. Pad 1 & 2 are directly connected.
From here, Pad 1 has a trace to pin 4, while Pad 2 goes to pin 15 of
the LS139

> Are there any questions remaining?

You're help has been wonderful Wolfgang. Thanks a lot. Now I have to
look for a 1541-II to install this :-) (Time to finish that 32KB
RAMBoard with the pieces I just got).

Regards,
Rodolfo Leal

Wolfgang Moser

unread,
Feb 13, 2004, 4:26:25 AM2/13/04
to
Hello Rodolfo,

> was sure that I traced all the pins, but missed this. Pins 20 and 22
> of the RAM chip are connected togheter. I missed it, because I was
> expecting a trace going to the socket.

I thought so. Good so now it's clear, that the RAMBOard
will work.

> Pad 3 is conected to pin 16 of the LS139

Really? Since pin 16 is the +5V power pin, it wouldn't
make much sense for that jumper localtion. If the
/SLCT signal (accordiing to my schematic version) would
be connected to +5V (jumper pads 2 and 3 connected
instead of 1 and 2), then the RAM chip will never be
enabled. Since the RAM can be disabled by other ways,
this would be a double option...


> I knew I missed to trace these pads. Pad 1 & 2 are directly connected.
> From here, Pad 1 has a trace to pin 4, while Pad 2 goes to pin 15 of
> the LS139

I see, that your interest was only to find out where
to connect A, B and C to. While it is my iinterest to
reconstruct this thing completely for further
discussions:
* other configuration options and settings
* other drive uses
and so on.

> You're help has been wonderful Wolfgang. Thanks a lot. Now I have to

Thanks for the feedback.

> look for a 1541-II to install this :-) (Time to finish that 32KB
> RAMBoard with the pieces I just got).

May I know, what type that 32KB versiion is? Who build it?
You aren't talking about Nicolas Welte's 6502-RamRom, are you?


Womo

Rodolfo Leal

unread,
Feb 13, 2004, 2:09:26 PM2/13/04
to
Wolfgang Moser <pw...@d81.de.invalid> wrote in message news:<c0i62b$6rg$1...@online.de>...

> > Pad 3 is conected to pin 16 of the LS139
>
> Really? Since pin 16 is the +5V power pin, it wouldn't
> make much sense for that jumper localtion.

Yes, it does. Maybe it's a redundant connection.

> I see, that your interest was only to find out where
> to connect A, B and C to. While it is my iinterest to
> reconstruct this thing completely for further
> discussions:
> * other configuration options and settings
> * other drive uses and so on.

It has been a good learning process for myself too.

> > (Time to finish that 32KB RAMBoard with the pieces I just got).
>

> May I know, what type that 32KB version is?

It's a homebrew version that I found out googling and webing (what a
words! :-)

> Who build it?

The layout it's the same as on the 8K-RAMBoard that Michael Klein has
in his site:

http://www.lb.shuttle.de/puffin/8k1541/8k1541.html

However, the 4364 is substituted by a 61256 32KB RAM chip, with the
lines A13 & A14 connected to the 6502. I haven't build it yet. Do you
think it will work?

> You aren't talking about Nicolas Welte's 6502-RamRom, are you?

No, though I'm convincing my wife to understand the urgent need to
have one for my Commodore equipment (That's why I'm building from
spares :-)

Regards,
Rodolfo Leal

Wolfgang Moser

unread,
Feb 13, 2004, 3:25:18 PM2/13/04
to
Good evening Rodolfo,

>>>Pad 3 is conected to pin 16 of the LS139
>>Really? Since pin 16 is the +5V power pin, it wouldn't
>

> Yes, it does. Maybe it's a redundant connection.

Well, ok then. Maybe this version was derived from
an earlier layout and that connection wasn't deleted
to save time.

Btw.: I think, that I do know now, why the capacitor
is connected in this way. I think, that it
suppresses glitches, that could occur, when
asynchronous logic with several inputs switches.

Fine, the schematics seem to be at the final stage
now (v 0.13), files on the temporary web section have
been updated.

> It has been a good learning process for myself too.

The best way to help, isn't it? Help the people so
that they become able to help themself (sometime).

>>May I know, what type that 32KB version is?
>
> It's a homebrew version that I found out googling
> and webing (what a words! :-)
>
>>Who build it?
>
> The layout it's the same as on the 8K-RAMBoard that
> Michael Klein has in his site:
>
> http://www.lb.shuttle.de/puffin/8k1541/8k1541.html
>
> However, the 4364 is substituted by a 61256 32KB RAM
> chip, with the lines A13 & A14 connected to the 6502.
> I haven't build it yet. Do you think it will work?

I don't think so. The problem is the chip enable
signal for the RAM. The 7442 decoder logic sets
the RAM-/OE (as well as RAM-/CS1) to low, when
the address range $8000..$9FFF is selected
(A15=H, A14=L, A13=L).

Regardless which RAM size you are using, only 8K
in that address range are usable. You will have to
use some bigger decoding logic to get a 32KB
expansion working.
Such a 32KB (or perhaps a 40KB one) expansion
must be enabled somewhere in the address range
from $2000 to $BFFF, but you need to interrupt to
chip selection siignals of the RAM, the both VIAs
(and the ROMs of course) to get it work. This is,
because these chips are mirrored all over the address
space from $2000...$7FFF. ...

>>You aren't talking about Nicolas Welte's 6502-RamRom, are you?
>
> No, though I'm convincing my wife to understand the urgent need to
> have one for my Commodore equipment (That's why I'm building from
> spares :-)

... Therefore Nicolas's 6502-RamRom intercepts the
whole 6502 CPU connection by replacing the processor
with a socket adapter. That way it is able to simulate
an externally unused address, when any internal
component is used.

Since Nicolas doesn't want to make (big) money from
his hardware projects, the PCB and GAL needed are
rather cheap (in my personal opinion), because he
mostly charges, what he self has to pay for and rounds
up the prices a little. Check out:
http://people.freenet.de/x1541/hardware/order.html

You can get the PCB and GAL for EUR 10. Since you only
want to have a RAM expansion, you don't need to buy the
FlashROM and can save some money.

Perhaps you are able to get the rest of the parts from
spares, although I think, that the socket adaptor would
be difficult to find somewhere.


Oh, did I mention, that I bought two of his PCBs myself?
I wrote a little test report at:
http://d81.de/6502RamRom/

Rodolfo Leal

unread,
Feb 13, 2004, 11:20:24 PM2/13/04
to
Wolfgang Moser <pw...@d81.de.invalid> wrote in message news:
> > It has been a good learning process for myself too.
>
> The best way to help, isn't it? Help the people so
> that they become able to help themself (sometime).

Without doubt. This experience awoke my hunger for the hardware side
of the business again. IT could become boring sometimes :-)

> Regardless which RAM size you are using, only 8K
> in that address range are usable.

Thanks for the info. I'll stick with a 6264 then.

> Since Nicolas doesn't want to make (big) money from
> his hardware projects, the PCB and GAL needed are
> rather cheap (in my personal opinion)

I'll show the power above this message. Maybe I can convince her to
buy the whole kit...

> Oh, did I mention, that I bought two of his PCBs myself?
> I wrote a little test report at:
> http://d81.de/6502RamRom/

Very interesting. Though SMD is a league beyond my current soldering
skills, I'll try out.

Regards,
Rodolfo Leal

Wolfgang Moser

unread,
Feb 14, 2004, 5:42:28 AM2/14/04
to
Rodolfo Leal wrote:

>Womo wrote:
>> http://d81.de/6502RamRom/
> Very interesting. Though SMD is a league beyond my current soldering
> skills, I'll try out.

The SMD part is only an alternative option for the RAM. You can
use three alternatiives:
32KB SRAM in a DIL28-3 (small DIP package) known from
Cache RAMs
32KB SRAM in a DIL28-6 ("standard" DIP size)
32KB SRAM in a SOIC (SMD packaging)

The other "hard" part of the PCB is the 6502-Adaption, but
Nicolas already described, that it becomes more simple, if
two 20pin SIP-adaption lines are use instead of a 40pin
adaption socket.

Wolfgang Moser

unread,
Feb 27, 2004, 12:53:02 AM2/27/04
to
Hello Rodolfo and all others of this thread,

> I made a couple of pictures of the board (up & down). Hope they
> ring the bell and finally I can know out how to connect it.
> The first picture is at the following address:
>
> http://www.geocities.com/cpu_loyal/files/RAMBoardUP.gif

I just saw, that arnold contains a test/demo diskette for
CLD's RAMBOard. Testing the RAM test program of this disk
(last file listed within the directory) within VICE showed,
that the test program searches for the RAMBOard at address
location $8000 (for an emulated 1541-II disk drive).

ftp://arnold.c64.org/pub/utils/c64apps/testdemo/ramboard.zip

This makes me more sure, that my earlier assumptions about
the adress space usage of the RAMBOard were correct.

For the 1571 disk drive, that RAMBOard tester seems to search
for the addon memory at address location $6000, for the 1541
(not -II, nor -C) it seems again to search for the RAM at
$8000.

path0s

unread,
Mar 1, 2004, 4:56:25 PM3/1/04
to
Glad to see my uploads being put to good use :)

Yeah, I have a ramboard 71.. From the pics I knew his wasn't one of those.

The 71 version of the ramboard I have has a 4 pin header on it that I'm not
sure what it connects to.. Could those ramobards be connected together for
super fast drive to drive nibbles maybe?

-P

"Wolfgang Moser" <pw...@d81.de.invalid> wrote in message

news:c1mlvt$i58$1...@online.de...

Wolfgang Moser

unread,
Mar 2, 2004, 1:16:01 PM3/2/04
to
Hello path0s, you wrote:

> Glad to see my uploads being put to good use :)

??? ... Oh, now I got it, you are talking from arnold.

> Yeah, I have a ramboard 71.. From the pics I knew his
> wasn't one of those.

_If_ there was only one 1571 revision of the RAMBOard.

> The 71 version of the ramboard I have has a 4 pin header on
> it that I'm not sure what it connects to.. Could those
> ramobards be connected together for super fast drive to
> drive nibbles maybe?

I don't think so. Probably these additional lines are needed
to install the RAMBOard into a 1571cr, the builtin disk drive
of a C128Dcr. Since the memory map of the 1571cr differs to
the one of standard 1571 drives, you may need at least one
additional addressing line, perhaps some more.

Aren't you willing to provide a schematic of your RAMBOard
version and perhaps some photos (better a 300dpi scan) of the
board as Rodolfo did?
By viewing onto such a schematic other or I may be able to
guess or deduce, what these connectors are really for.

path0s

unread,
Mar 3, 2004, 2:18:52 PM3/3/04
to
Actually, I started doing this at one time. Got pretty far. I'll have to dig
around to see if I still have em. They're in eagle format, but I could make
some images out of em if I still have it.

-P

"Wolfgang Moser" <pw...@d81.de.invalid> wrote in message

news:c22j0t$a1v$1...@online.de...

Wolfgang Moser

unread,
Mar 3, 2004, 4:43:33 PM3/3/04
to
path0s wrote:
> Actually, I started doing this at one time. Got pretty far. I'll have to dig
> around to see if I still have em. They're in eagle format, but I could make
> some images out of em if I still have it.

Hi Pathos, would be cool. Since I use Eagle myself (freeware
light edition), you could send me the files and I'll convert
them to PNGs. I already did this all for Rodolfo's version
(constructing schematic and board with Eagle and creating PNGs
for publishing them on my web space).

Reply all
Reply to author
Forward
0 new messages