Commodore 8296GD

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Commodore 8296GD

Michał Pleban
Dear all,

>From time to time I collect 8296D computers at eBay, mostly to strip
internal drives from them for my 700's :-)

Today I repaired one 700, so I went to a 8296D which has been sitting
idle for many months to strip the drive. Upon opening it, I saw an
additional board attached to the motherboard, piggybacked on the CRTC
and character ROM.

>From a short mention on Andre Fachat's website I reckon it must be the
8296GD cariant, with a hi-res graphics adapter. The "adapter" is
actually just a small board with a 6545, EPROM, 8 TTL chips and 4
DIP-switches.

There are these ROMs in this machine:

324243-04 8296D DIN
324993-02 HiRes BASIC
324992-02 HiRes Emulator
824242-01 DIN8296/8296D (in the video board)

The computer powers up, emitting strange beeps from the buzzer, and
displays standard BASIC 4.0 welcome message. The keyboard has some keys
missing unfortunately.

I haven't been able to find any documentation on this graphics card and
I don't know how to utilize it from the BASIC. I will dump the ROMs and
try to look at them, but maybe someone has documentation scanned which I
could look at?

Regards,
Michau.


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gal programming on windows 7.

Didier Derny
Lattice has release recently a version of ispLever classic 1.6 (august 2012)
It also support GALs (obsolete components check box in device selection)

It might be easier than dos based software.

Not fully tested but I'll try it soon.

--
Didier





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Re: Commodore 8296GD

Michał Pleban
In reply to this post by Michał Pleban
OK, after a quick look ath the ROM dump (had to download it via CBMLINK,
as my programmer does not read 2532's), I was able to play with the board.

First, the board needs to be initialized by:

SYS 36864

Then, all the standard commands from other PET/CBM-II graphics bards
work, i.e. DISPLAY, PLOT, MAP and so on.

The board has 512x256 resolution.

Regards,
Michau


Michał Pleban wrote:

> Dear all,
>
>>From time to time I collect 8296D computers at eBay, mostly to strip
> internal drives from them for my 700's :-)
>
> Today I repaired one 700, so I went to a 8296D which has been sitting
> idle for many months to strip the drive. Upon opening it, I saw an
> additional board attached to the motherboard, piggybacked on the CRTC
> and character ROM.
>
>>From a short mention on Andre Fachat's website I reckon it must be the
> 8296GD cariant, with a hi-res graphics adapter. The "adapter" is
> actually just a small board with a 6545, EPROM, 8 TTL chips and 4
> DIP-switches.
>
> There are these ROMs in this machine:
>
> 324243-04 8296D DIN
> 324993-02 HiRes BASIC
> 324992-02 HiRes Emulator
> 824242-01 DIN8296/8296D (in the video board)
>
> The computer powers up, emitting strange beeps from the buzzer, and
> displays standard BASIC 4.0 welcome message. The keyboard has some keys
> missing unfortunately.
>
> I haven't been able to find any documentation on this graphics card and
> I don't know how to utilize it from the BASIC. I will dump the ROMs and
> try to look at them, but maybe someone has documentation scanned which I
> could look at?
>
> Regards,
> Michau.
>
>
>        Message was sent through the cbm-hackers mailing list
>


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Re: Commodore 8296GD

Rhialto
On Sat 29 Sep 2012 at 20:14:08 +0200, Micha? Pleban wrote:
> OK, after a quick look ath the ROM dump (had to download it via CBMLINK,
> as my programmer does not read 2532's), I was able to play with the board.

Well, as the board seems simpler than the HSG board... (somebody wrote
that the chip on that was rather complicated to emulate)
if you find out enough details about this, I'd be happy to write an
emulation for it to include in VICE.

-Olaf.
--
___ Olaf 'Rhialto' Seibert  -- There's no point being grown-up if you
\X/ rhialto/at/xs4all.nl    -- can't be childish sometimes. -The 4th Doctor

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Re: Commodore 8296GD

Michał Pleban
Hello!

Rhialto wrote:

> Well, as the board seems simpler than the HSG board... (somebody wrote
> that the chip on that was rather complicated to emulate)
> if you find out enough details about this, I'd be happy to write an
> emulation for it to include in VICE.

Sure, I'll try to figure it out. As I can see, it just uses the original
CRTC chip by "faking" the character set somehow as hires graphics. The
bitmap to display most probably comes from the extra RAM. So far I was
able to write a simple bitmap displayer in BASIC ;-)

https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-snc6/222187_10151041489882026_2036796824_n.jpg

Regards,
Michau.


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Re: Commodore 8296GD

Rhialto
On Sat 29 Sep 2012 at 22:02:17 +0200, Micha? Pleban wrote:

>
> Rhialto wrote:
>
> > Well, as the board seems simpler than the HSG board... (somebody wrote
> > that the chip on that was rather complicated to emulate)
> > if you find out enough details about this, I'd be happy to write an
> > emulation for it to include in VICE.
>
> Sure, I'll try to figure it out. As I can see, it just uses the original
> CRTC chip by "faking" the character set somehow as hires graphics.

Sounds much like what the DWW board is doing. I posted about that in
this very mailing list. It has 8 banks of 1KB. It (most likely) used the
offset into character cell memory, as output by the CRTC, as index into
a 1 KB block of bitmap memory, combining it with the vertical offset
into the character (0-7) (also as output by the CRTC) to select which bank.
(Except that the DWW was designed before the CRTC was used, but I'm sure
the same counters were present in the design anyway)

> The
> bitmap to display most probably comes from the extra RAM.

Yes, that is what I read elsewhere too. The "extra 32K" aka the
"inaccessible 32K". Not that they're totally inaccessible: those 32 K
are the second part of the non-expansion RAM (the other 64 KB of the 128
KB are expansion RAM), and therefore would map from $8000-$FFFF if there
were not ROM and I/O there.

And in fact you can access parts of it: $8xxx is normal screen
(character cell) memory. $9xxx and $Axxxx can be easily jumpered to be
RAM as well (if you don't have EPROMs installed in the sockets of the
same address). And iirc there is also a 'jumper' option (but not so
easily accessible) to connect a user port line to the NOROM line and
make it possible to map out all ROMs, thereby uncovering even more of
that RAM).

Given this, the interesting issue gets to be: Where is the bitmap, and
how is it accessed by the CPU?

Given the resolution you mention (512 x 256) it would need 16 KB of
memory, or half of that 32 KB space. If normal text output would remain
working, and perhaps they thought it was nice if the $9xxx and $Axxx
would keep working as it was, it should be at $C000-$FFFF. Somehow.

I wonder why that resolution was chosen, and not 640 x 200 (which is 8 x
(80 x 25)). That would make it much more compatible with the text
screen.

> So far I was
> able to write a simple bitmap displayer in BASIC ;-)
>
> https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-snc6/222187_10151041489882026_2036796824_n.jpg

Looks good!

> Regards,
> Michau.
>
>
>        Message was sent through the cbm-hackers mailing list

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Re: Commodore 8296GD

Michał Pleban
Hello!

Rhialto wrote:

> Sounds much like what the DWW board is doing. I posted about that in
> this very mailing list. It has 8 banks of 1KB. It (most likely) used the
> offset into character cell memory, as output by the CRTC, as index into
> a 1 KB block of bitmap memory, combining it with the vertical offset
> into the character (0-7) (also as output by the CRTC) to select which bank.
> (Except that the DWW was designed before the CRTC was used, but I'm sure
> the same counters were present in the design anyway)

Yes. However, this board is even more simple - no PIA, no I/O chips
whatsoever, just some TTL glue logic. Maybe it uses some CRTC address
outputs as signal lines (like the CBM-II does) because otherwise I don't
know how it would even turn the graphics on.

> Yes, that is what I read elsewhere too. The "extra 32K" aka the
> "inaccessible 32K". Not that they're totally inaccessible: those 32 K
> are the second part of the non-expansion RAM (the other 64 KB of the 128
> KB are expansion RAM), and therefore would map from $8000-$FFFF if there
> were not ROM and I/O there.

Yes, this is probable. So far I looked at the initialization code at
$9000, and the first thing it does, it copies some routines to RAM at
$8800. So most probably the bitmap data is in the extra RAM, and the
graphics operations require banking out the ROMs - thus the routines
itself must be copied to that RAM. I still do not know how it banks them
out, though.

> And in fact you can access parts of it: $8xxx is normal screen
> (character cell) memory. $9xxx and $Axxxx can be easily jumpered to be
> RAM as well (if you don't have EPROMs installed in the sockets of the
> same address). And iirc there is also a 'jumper' option (but not so
> easily accessible) to connect a user port line to the NOROM line and
> make it possible to map out all ROMs, thereby uncovering even more of
> that RAM).

Well, there are ROMs at $9000 and $A000 of course, the HiRes routines
and BASIC extension :-)

> Given this, the interesting issue gets to be: Where is the bitmap, and
> how is it accessed by the CPU?

Yes, that's what I'm trying to figure out :-)

> Given the resolution you mention (512 x 256) it would need 16 KB of
> memory, or half of that 32 KB space. If normal text output would remain
> working, and perhaps they thought it was nice if the $9xxx and $Axxx
> would keep working as it was, it should be at $C000-$FFFF. Somehow.

My guess too. And yes, the normal screen still works independently of
the graphics - if you turn out the graphics, the text screen remains as
it was (and vice versa).

> I wonder why that resolution was chosen, and not 640 x 200 (which is 8 x
> (80 x 25)). That would make it much more compatible with the text
> screen.

Maybe to retain compatibility with boards based on the Thomson chip,
which used that resolution?

Regards,
Michau.

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Re: Commodore 8296GD

Steve Gray
In reply to this post by Michał Pleban
I got some high-res pictures of this board from someone on forum64.de and I was hoping to reverse engineer this board as part of my "UltraPET" project (http://www.6502.org/users/sjgray/projects/ultrapet/index.html). I mention this board on my page.
 
Anyway, this board is refered to as the HRE or High-Res Emulator as it is supposed to be software compatible to the Commodore HSG (High Speed Graphik) board.
 
Perhaps you can try some of the demos I typed in and confirm if they work or not on the HRE board!
 
The CRTC chip can be reprogrammed and I assume that the HRE board bypasses the character set rom and shifts out the actual memory byte as-is. If the character cell height is set to 1 pixel then you effectively have a "graphics" mode.
If the video memory is somehow diverted to the expansion memory that would explain how the normal screen is untouched, and makes sense. It sounds like a cool board.
 
I'd love to get this board cloned!
 
Steve
From: Michał Pleban <[hidden email]>
To: "[hidden email]" <[hidden email]>
Sent: Saturday, September 29, 2012 8:59:45 AM
Subject: Commodore 8296GD

Dear all,

>From time to time I collect 8296D computers at eBay, mostly to strip
internal drives from them for my 700's :-)

Today I repaired one 700, so I went to a 8296D which has been sitting
idle for many months to strip the drive. Upon opening it, I saw an
additional board attached to the motherboard, piggybacked on the CRTC
and character ROM.

>From a short mention on Andre Fachat's website I reckon it must be the
8296GD cariant, with a hi-res graphics adapter. The "adapter" is
actually just a small board with a 6545, EPROM, 8 TTL chips and 4
DIP-switches.

There are these ROMs in this machine:

324243-04 8296D DIN
324993-02 HiRes BASIC
324992-02 HiRes Emulator
824242-01 DIN8296/8296D (in the video board)

The computer powers up, emitting strange beeps from the buzzer, and
displays standard BASIC 4.0 welcome message. The keyboard has some keys
missing unfortunately.

I haven't been able to find any documentation on this graphics card and
I don't know how to utilize it from the BASIC. I will dump the ROMs and
try to look at them, but maybe someone has documentation scanned which I
could look at?

Regards,
Michau.


      Message was sent through the cbm-hackers mailing list


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Re: Commodore 8296GD

Rhialto
On Sun 30 Sep 2012 at 10:05:55 -0700, Steve Gray wrote:
> I got some high-res pictures of this board from someone on forum64.de and I was hoping to reverse engineer this board as part of my "UltraPET" project (http://www.6502.org/users/sjgray/projects/ultrapet/index.html). I mention this board on my page.

VICE currently doesn't allow SuperPET and 8x96 memory expansions at the
same time. My first impression about that was that that would probably
be because the expansion connector is incompatible between 8032 and 8296
machines, and/or you can't connect 2 boards to that connector at once.
But the SuperPET board(s) don't connect via that connector, so that is a
moot point.

I didn't try it, but if the restriction were simply removed from VICE
with no other changes, I expect that the 8x96 memory would override the
SuperPET memory. I.e. if you enable one of the 8x96 expansion banks in
the $8000-$C000 range, you would no longer have access to the SuperPET
memory at $9000-$A000.

In reality, I'd expect the SuperPET memory to override though, since it
is "closer" to the CPU (the CPU is moved to the expansion board).

I'd think that the former way would be more useful, since keeping the
SuperPET memory block visible at all times would make it impossible to
access 2 x 4KB of 8x96 memory (4 KB in each of 2 banks).

-Olaf.
--
___ Olaf 'Rhialto' Seibert  -- There's no point being grown-up if you
\X/ rhialto/at/xs4all.nl    -- can't be childish sometimes. -The 4th Doctor

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Re: Commodore 8296GD

André Fachat
I implemented this either-or because I didn't think that was a realistic combination.

I am not sure what happens when you really do it, it depends on whether the superpet assigns the norom line (on the cpu socket on an nc pin, pin 5 iirc). Otherwise there would be an address conflict

In vice I would like to see the real world behaviour, at least as default...

André



Rhialto <[hidden email]> schrieb:
On Sun 30 Sep 2012 at 10:05:55 -0700, Steve Gray wrote:
I got some high-res pictures of this board from someone on forum64.de and I was hoping to reverse engineer this board as part of my "UltraPET" project (http://www.6502.org/users/sjgray/projects/ultrapet/index.html). I mention this board on my page.

VICE currently doesn't allow SuperPET and 8x96 memory expansions at the
same time. My first impression about that was that that would probably
be because the expansion connector is incompatible between 8032 and 8296
machines, and/or you can't connect 2 boards to that connector at once.
But the SuperPET board(s) don' t connect via that connector, so that is a
moot point.

I didn't try it, but if the restriction were simply removed from VICE
with no other changes, I expect that the 8x96 memory would override the
SuperPET memory. I.e. if you enable one of the 8x96 expansion banks in
the $8000-$C000 range, you would no longer have access to the SuperPET
memory at $9000-$A000.

In reality, I'd expect the SuperPET memory to override though, since it
is "closer" to the CPU (the CPU is moved to the expansion board).

I'd think that the former way would be more useful, since keeping the
SuperPET memory block visible at all times would make it impossible to
access 2 x 4KB of 8x96 memory (4 KB in each of 2 banks).

-Olaf.

--
Diese Nachricht wurde von meinem Android-Mobiltelefon mit K-9 Mail gesendet.
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Re: Commodore 8296GD

Michał Pleban
In reply to this post by Steve Gray
Hello!

Steve Gray wrote:

> Anyway, this board is refered to as the HRE or High-Res Emulator as it
> is supposed to be software compatible to the Commodore HSG (High Speed
> Graphik) board.
> I have a web page for the HSG here:
> http://www.6502.org/users/sjgray/computer/hsg/index.html
>  
> Perhaps you can try some of the demos I typed in and confirm if they
> work or not on the HRE board!

I would like to try them, but I see yu posted them as a 4040 image - I
don't have a drive capable of burning such image :-) Only 8250LP's and
1001's. Can you repost them in a different format?

> I'd love to get this board cloned!

If some good soul offers to reverse-engineer it, I could send it over
given that it is then shipped back to me.

Regards,
Michau.

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Re: Commodore 8296GD

Anders Carlsson
Michał Pleban wrote:

> I would like to try them, but I see yu posted them as a 4040 image - I
> don't have a drive capable of burning such image :-) Only 8250LP's and
> 1001's. Can you repost them in a different format?

I think Marko's cbmconvert (among other command line and GUI oriented tools)
will be useful when extracting files between different disk image formats.
While I didn't expect this image, I suppose it doesn't contain any random
access sectors or something else that would be difficult to convert.

Best regards

Anders Carlsson


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Re: Commodore 8296GD

Steve Gray
In reply to this post by Michał Pleban
 Michał ,
 
I can re-post a 8250 format disk for you. It just happened that I had an MSD drive available when I typed them.
 
would love to reverse engineer that board. If you don't mind lending it to me for a couple months... you can see I don't work too fast ;-)
 
Steve

 
From: Michał Pleban <[hidden email]>
To: [hidden email]
Sent: Monday, October 1, 2012 3:47:47 AM
Subject: Re: Commodore 8296GD

Hello!

Steve Gray wrote:

> Anyway, this board is refered to as the HRE or High-Res Emulator as it
> is supposed to be software compatible to the Commodore HSG (High Speed
> Graphik) board.
> I have a web page for the HSG here:
> http://www.6502.org/users/sjgray/computer/hsg/index.html

> Perhaps you can try some of the demos I typed in and confirm if they
> work or not on the HRE board!

I would like to try them, but I see yu posted them as a 4040 image - I
don't have a drive capable of burning such image :-) Only 8250LP's and
1001's. Can you repost them in a different format?

> I'd love to get this board cloned!

If some good soul offers to reverse-engineer it, I could send it over
given that it is then shipped back to me.

Regards,
Michau.

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Re: Commodore 8296GD

Michał Pleban
Hello!

Steve Gray wrote:

> I can re-post a 8250 format disk for you. It just happened that I had an
> MSD drive available when I typed them.

Please do.

> would love to reverse engineer that board. If you don't mind lending it
> to me for a couple months... you can see I don't work too fast ;-)

Sure, no problem, I am slow nowadays myself with all the company stuff
on my head... How's your P500 by the way? ;-)

Regards,
Michau.



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Re: Commodore 8296GD

MikeS
In reply to this post by Steve Gray

If Michau sends it to you I'm willing to help out any way I can; a worthy project indeed!
 
mike
----- Original Message -----
Sent: Monday, October 01, 2012 11:16 AM
Subject: Re: Commodore 8296GD

 Michał ,
 
I can re-post a 8250 format disk for you. It just happened that I had an MSD drive available when I typed them.
 
would love to reverse engineer that board. If you don't mind lending it to me for a couple months... you can see I don't work too fast ;-)
 
Steve

 
From: Michał Pleban <[hidden email]>
To: [hidden email]
Sent: Monday, October 1, 2012 3:47:47 AM
Subject: Re: Commodore 8296GD

Hello!

Steve Gray wrote:

> Anyway, this board is refered to as the HRE or High-Res Emulator as it
> is supposed to be software compatible to the Commodore HSG (High Speed
> Graphik) board.
> I have a web page for the HSG here:
> http://www.6502.org/users/sjgray/computer/hsg/index.html

> Perhaps you can try some of the demos I typed in and confirm if they
> work or not on the HRE board!

I would like to try them, but I see yu posted them as a 4040 image - I
don't have a drive capable of burning such image :-) Only 8250LP's and
1001's. Can you repost them in a different format?

> I'd love to get this board cloned!

If some good soul offers to reverse-engineer it, I could send it over
given that it is then shipped back to me.

Regards,
Michau.

      Message was sent through the cbm-hackers mailing list


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Re: Commodore 8296GD

Rhialto
In reply to this post by Michał Pleban
On Mon 01 Oct 2012 at 17:44:03 +0200, Micha? Pleban wrote:
> Sure, no problem, I am slow nowadays myself with all the company stuff
> on my head...

I double-checked in the "8296 Addendum" and it is actually a line called
/RAM_ON which can be connected to the userport, selectable by a jumper.

There are also 2 more jumpers for /RAMSEL_9 and /RAMSEL_A.

If you close those, you can programmatically read all of the "missing"
32 KB of RAM.  It may well be that the installation instructions of the
card include a step to close these jumpers.

For writing, there is a write-through the ROMs to RAM - except in the
I/O area. If it weren't for this, you could write a hi-res picture
without these tricks.

For reference, see
http://www.zimmers.net/anonftp/pub/cbm/pet/manuals/8296supplement/8296supplement.html
pages 4 and 5:

2.3. Modifications to the main memory system

By contrast with the CBM 8032, each address in the 64 k main
memory is covered by RAM. A write command into any address (apart
from I/O) causes the corresponding RAM address to be written at,
and a read command reads from RAM between $0000 and $8FFF; above
$9000 from the empty [EP]ROM sockets, from the ROM or from the I/O
devices.

RAM $0000 - $FFFF
Empty socket $9000 - $AFFF
ROM $B000 - $FFFF. except $E8XX
I/O $E800 - $E8FF

The memory system for CPU read accesses can be modified by means of
the signals /RAM SEL 9, /RAM SEL A, and /RAM ON (J4, Pins 12, 13, 14)
in accordance with the following table:


[The first line represents the normal config.  In my machine I have
jumpered J4 (the expansion bus) pins 12 and 13 to ground which gives me
8K of additional RAM which is not cleared on reset. Ground pins are
available in the adjecent row.]


[/NO ROM = 1; see page 12 for more cases]
+-----+--------+------------+-------------------------------------------------+
|     |Control |            |                                                 |
|     |Register|            |      main memory $8000 - $FFFF        [UB1-UB8] |
|     |        |            |      [$0000 - $7FFF is always RAM from UB1-UB8] |
|     |$FFF0   |            |                                                 |
+-----+--------+------------+-------------------------------------------------+
|     |    I/O |___ ___ ___ |              E000                               |
| ___ |    peek|RAM RAM RAM | E800  F000  -E7FF  B000  A000  9000  8000       |
| NO_ |    thr.|___ ___ ___ |              E900                               |
| ROM |CR7 CR6 |ON  S.9 S.A |-E8FF -FFFF  -EFFF -DFFF -AFFF -9FFF -8FFF       |
+-----+--------+------------+-------------------------------------------------+
|     |        |            |                                                 |
|  1  | 0   X  | 1   1   1  | I/O  Kernal Editor BASIC EPROM EPROM SCREEN     |
|     |        |            |                                                 |
|  1  | 0   X  | 1   1   0  | I/O  Kernal Editor BASIC  RAM  EPROM SCREEN     |
|     |        |            |                               +-----+           |
|  1  | 0   X  | 1   0   1  | I/O  Kernal Editor BASIC EPROM  RAM  SCREEN     |
|     |        |            |                         +-----+                 |
|  1  | 0   X  | 1   0   0  | I/O  Kernal Editor BASIC  RAM   RAM  SCREEN     |
|     |        |            |                   +-----+                       |
|  1  | 0   X  | 0   1   1  | I/O  Kernal Editor  RAM   RAM   RAM  SCREEN     |
|     |        |            |            +------+                             |
|  1  | 0   X  | 0   0   1  | I/O  Kernal  RAM    RAM   RAM   RAM  SCREEN     |
|     |        |            |     +------+                                    |
|  1  | 0   1  | 0   X   0  | I/O   RAM    RAM    RAM   RAM   RAM  SCREEN     |
|     |        |            |+----+                                           |
|  1  | 0   0  | 0   X   0  | RAM   RAM    RAM    RAM   RAM   RAM  SCREEN     |
|     |        |            |                                                 |
+-----+--------+------------+-------------------------------------------------+
SCREEN: 2000 bytes for screen memory, and 2096 bytes of available RAM.



  - 4 -


2.4. User Jumper

These three signals can be either fixed or programmable via
user jumpers. Bits 0, 1 and 2 are used for control under program
control.

[In my machine these jumpers are not true jumpers.  You must solder two
very tiny locations on the motherboard together to close the jumpers.
Also these locations are rather far apart in the midst of various other
tiny traces. I opted to use J4 instead which has JU1 and JU2 effectively
accessible.]

Jumper      Description of function

            _________
 JU1        RAM SEL A = LOW
            _________
 JU2        RAM SEL 9 = LOW
            _________
 JU3        RAM SEL A to Port A0
            _________
 JU4        RAM SEL 9 to Port A1
            ______
 JU5        RAM ON    to Port A2


To use the user jumpers JU3 to JU5, Pins 0, 1 and 2 of the user
port must be programmed to output.

DR = 59459 ($E843)
DA = 59471 ($E84F)

POKE DR, PEEK (DR) OR 7

The desired combination of bits (0 ... 7) can then be poked into
the port register DA.

N.B. When using JU3, JU4 and JU5, make sure that the user port is
     not written at accidentally. This can happen for instance in
     a number of text processing programs, which emulate a
     Centronics interface via the user port.

                ______
     The signal RAM ON must be high at the start, as it is not
     otherwise possible to complete the POWER ON routine in the ROM.

                                - 5 -


-Olaf.
--
___ Olaf 'Rhialto' Seibert  -- There's no point being grown-up if you
\X/ rhialto/at/xs4all.nl    -- can't be childish sometimes. -The 4th Doctor

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Re: Commodore 8296GD

Steve Gray
In reply to this post by Michał Pleban
I will try to post a D82 for you tonight, but no promises :)
Thanks! I'll see if Mike can help with the reverse engineering or perhaps building a wirewrap version.
 
My P500 is not happy. I've tested all the socketed main chips and they are ok. The voltages look ok. There seems to be activity in the system but I'm not sure where it's going bad. I suspect the 6525 might be bad but it's soldered in, and since my eyes are going bad I haven't been too keen on soldering these days. A also need to convert it from PAL to NTSC, which again will need some soldering.
 
Steve
From: Michał Pleban <[hidden email]>
To: [hidden email]
Sent: Monday, October 1, 2012 11:44:03 AM
Subject: Re: Commodore 8296GD

Hello!

Steve Gray wrote:

> I can re-post a 8250 format disk for you. It just happened that I had an
> MSD drive available when I typed them.

Please do.

> would love to reverse engineer that board. If you don't mind lending it
> to me for a couple months... you can see I don't work too fast ;-)

Sure, no problem, I am slow nowadays myself with all the company stuff
on my head... How's your P500 by the way? ;-)

Regards,
Michau.



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Re: Commodore 8296GD

Steve Gray
In reply to this post by Michał Pleban
I posted a picture of the board here:
 
It looks like it would be pretty easy to figure out...
Steve

From: Michał Pleban <[hidden email]>
To: [hidden email]
Sent: Monday, October 1, 2012 11:44:03 AM
Subject: Re: Commodore 8296GD

Hello!

Steve Gray wrote:

> I can re-post a 8250 format disk for you. It just happened that I had an
> MSD drive available when I typed them.

Please do.

> would love to reverse engineer that board. If you don't mind lending it
> to me for a couple months... you can see I don't work too fast ;-)

Sure, no problem, I am slow nowadays myself with all the company stuff
on my head... How's your P500 by the way? ;-)

Regards,
Michau.



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Re: Commodore 8296GD

Rhialto
On Mon 01 Oct 2012 at 13:02:16 -0700, Steve Gray wrote:
> I posted a picture of the board here:
> http://www.6502.org/users/sjgray/temp/HRGE_Front.jpg
>  
> It looks like it would be pretty easy to figure out...
> Steve

Great picture!

The first post mentioned that it was piggybacked onto the character
generator ROM and the CRTC... and so the one on the board is a *second*
CRTC? Interesting...

(Or does it merely go into the socket of the CRTC and the one we see in
the picture is the one that used to be there?)

-Olaf.
--
___ Olaf 'Rhialto' Seibert  -- There's no point being grown-up if you
\X/ rhialto/at/xs4all.nl    -- can't be childish sometimes. -The 4th Doctor

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Re: Commodore 8296GD

Steve Gray
No, the original CRTC chip and CHARROM are transplanted to this board.
Here's the back of the board:
 
However, there IS a DIFFERENT graphics card for PET that contains it's own CRTC chip. Perhaps for another discussion later:
 
Steve

From: Rhialto <[hidden email]>
To: [hidden email]
Sent: Monday, October 1, 2012 6:18:26 PM
Subject: Re: Commodore 8296GD

On Mon 01 Oct 2012 at 13:02:16 -0700, Steve Gray wrote:
> I posted a picture of the board here:
> http://www.6502.org/users/sjgray/temp/HRGE_Front.jpg
>  
> It looks like it would be pretty easy to figure out...
> Steve

Great picture!

The first post mentioned that it was piggybacked onto the character
generator ROM and the CRTC... and so the one on the board is a *second*
CRTC? Interesting...

(Or does it merely go into the socket of the CRTC and the one we see in
the picture is the one that used to be there?)

-Olaf.
--
___ Olaf 'Rhialto' Seibert  -- There's no point being grown-up if you
\X/ rhialto/at/xs4all.nl    -- can't be childish sometimes. -The 4th Doctor

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