New CBM-II discoveries

[Steve Gray]

Hi all,

Anyone interested in CBM-II stuff, we've had a couple interesting discoveries and I've posted them on my CBM-II webpage.

Both of these items were known to have been in the commodore labs, but until now have been lost:

1) The Z80 co-processor board. Mentioned in sales literature but never seen. We have schematics that seem to indicate it was close to production. The interesting thing about this board is it was to work on both the P and B series. We don't know how close it was, and we don't have any firmware.

2) The Hires Color Grafik board. This is similar to the PET/CBM High-speed Graphik (HSG) board, using the same Thomson EF chip, but with RGB colour! The schematics shows it to be complete but lacking a part# so again we don't know how far along these were.

Very interesting stuff!

http://www.6502.org/users/sjgray/computer/cbm2/index.html

Steve

[Steve Gray]

Oh, I forgot to mention. Thanks go to Bil Herd for the Hires card schematics, and to Frank Hughes for the Z80 schematics!

Steve

---

From: Steve Gray <[hidden email]>
To: CBM Hackers List <[hidden email]>
Sent: Friday, June 22, 2018 5:01 PM
Subject: New CBM-II discoveries

Hi all,

Anyone interested in CBM-II stuff, we've had a couple interesting discoveries and I've posted them on my CBM-II webpage.

Both of these items were known to have been in the commodore labs, but until now have been lost:

1) The Z80 co-processor board. Mentioned in sales literature but never seen. We have schematics that seem to indicate it was close to production. The interesting thing about this board is it was to work on both the P and B series. We don't know how close it was, and we don't have any firmware.

2) The Hires Color Grafik board. This is similar to the PET/CBM High-speed Graphik (HSG) board, using the same Thomson EF chip, but with RGB colour! The schematics shows it to be complete but lacking a part# so again we don't know how far along these were.

Very interesting stuff!

http://www.6502.org/users/sjgray/computer/cbm2/index.html

Steve

[Christian Dirks]

Am 22.06.2018 um 23:40 schrieb Steve Gray:

> 1) The Z80 co-processor board.
> 2) The Hires Color Grafik board.

Great stuff!
I wonder if there will be firm-/software to make these useable...


--
Christian Dirks
[hidden email]
Vorster Str. 66
47918 Tönsivorst

2. Stellv. Vorsitzender
Verein zum Erhalt klassischer Computer e.V.
http://www.classic-computing.de/

[Steve Gray]

Well, hopefully the roms can be found, even if in a printout somewhere. Otherwise, we'll need to make our own.

The Z80 processor is probably close enough to the 8088 board that adapting the CBM-side code would be possible.Someone would need to adapt a CP/M bios.

The Hires board can probably use the HSG firmware with only small changes.There are 3 bitplanes instead of one, so to do colour we probably have to figure out how to select the proper bitplane before issuing a draw command. you probably need to repeat the same draw command with a different plane selected corresponding to the on bits of the desired colour. I started disassembling the HRG firmware a few years ago but never finished. 

Steve

---

From: Christian Dirks <[hidden email]>
To: [hidden email]
Sent: Saturday, June 23, 2018 5:31 AM
Subject: Re: New CBM-II discoveries

Am 22.06.2018 um 23:40 schrieb Steve Gray:

> 1) The Z80 co-processor board.
> 2) The Hires Color Grafik board.

Great stuff!
I wonder if there will be firm-/software to make these useable...


--
Christian Dirks
[hidden email]
Vorster Str. 66
47918 Tönsivorst

2. Stellv. Vorsitzender
Verein zum Erhalt klassischer Computer e.V.
http://www.classic-computing.de/

[smf]

On 24/06/2018 02:32, Steve Gray wrote:

> you probably need to repeat the same draw command with a different plane selected corresponding to the on bits of the desired colour.

Using one port on the 6523 you can select which (any or all) of the
drams will receive write strobes.

The data in on each chip has an or gate, which is fed by another 6523 port.

There is some RMW stuff going on that I don't understand.

It is likely you can draw colour in one operation.

[Bill Degnan]

On Mon, Jun 25, 2018 at 4:25 AM smf <[hidden email]> wrote:

On 24/06/2018 02:32, Steve Gray wrote:

> you probably need to repeat the same draw command with a different plane selected corresponding to the on bits of the desired colour.

Using one port on the 6523 you can select which (any or all) of the
drams will receive write strobes.

The data in on each chip has an or gate, which is fed by another 6523 port.

There is some RMW stuff going on that I don't understand.

It is likely you can draw colour in one operation.

Will it be 160 x 100 hi-res mode? black, blue, green, cyan, red, magenta, yellow, and white...64 color combos.  There is I read for the 8032 color that never launched a 32K Screen Edit ROM.  Works with BASIC 4 and if this ROM exists may be convertable to be used in the CBM-II

b 

[Steve Gray]

The hires card uses the thomson ef series vdp chips. There are several variations which have different resolutions from 512*256, 512*512, to 1024*512. These are strictly bitmap mode chips so no need to modify the screen editor code. Output will be to a separate monitor.

Steve

On Jun 25, 2018, at 8:38 AM, Bill Degnan <[hidden email]> wrote:

On Mon, Jun 25, 2018 at 4:25 AM smf <[hidden email]> wrote:

On 24/06/2018 02:32, Steve Gray wrote:

> you probably need to repeat the same draw command with a different plane selected corresponding to the on bits of the desired colour.

Using one port on the 6523 you can select which (any or all) of the
drams will receive write strobes.

The data in on each chip has an or gate, which is fed by another 6523 port.

There is some RMW stuff going on that I don't understand.

It is likely you can draw colour in one operation.

Will it be 160 x 100 hi-res mode? black, blue, green, cyan, red, magenta, yellow, and white...64 color combos.  There is I read for the 8032 color that never launched a 32K Screen Edit ROM.  Works with BASIC 4 and if this ROM exists may be convertable to be used in the CBM-II

b 

[Steve Gray]

I'm looking at the schematic, trying to understand it.

Each bitplane uses eight 64Kx1 drams and the hardware can address a single bit from each plane.

I agree... It can then write the colour in a single operation. That colour is set via the 6523 Port A - 3 bits for the colour and 3 bits enable writing. I'm not sure why you wouldn't always write the 3 colour bits but maybe I just haven't figured that out yet.

It looks like we CAN'T replace the 64Kx1 drams with 64Kx8 due to the method used by the EF chip to select individual bits. So not much chance of reducing the parts count. In fact it would be trivial to ADD additional bitplanes to make it support more colours. Imagine having 8 bitplanes and doing 512x512 pixels with 256 colours per pixel !

Steve

---

From: smf <[hidden email]>
To: [hidden email]
Sent: Monday, June 25, 2018 4:24 AM
Subject: Re: New CBM-II discoveries

On 24/06/2018 02:32, Steve Gray wrote:

> you probably need to repeat the same draw command with a different plane selected corresponding to the on bits of the desired colour.

Using one port on the 6523 you can select which (any or all) of the
drams will receive write strobes.

The data in on each chip has an or gate, which is fed by another 6523 port.

There is some RMW stuff going on that I don't understand.

It is likely you can draw colour in one operation.

[vossi]

A problem is the 6523 - Its very hard to find.
It is only available from mos!



-----
greets
Christian
--
Sent from: http://cbm-hackers.2304266.n4.nabble.com/

[Michał Pleban]

vossi wrote:

> A problem is the 6523 - Its very hard to find.
> It is only available from mos!

I suppose it's time somebody built a replacement :-) Without the
interrupt logic of the 6525, it should be fairly easy.

Regards,
Michau.

[MiaM]

Den Tue, 26 Jun 2018 11:24:44 +0200 skrev Michał Pleban
<[hidden email]>:
> vossi wrote:
>
> > A problem is the 6523 - Its very hard to find.
> > It is only available from mos!
>
> I suppose it's time somebody built a replacement :-) Without the
> interrupt logic of the 6525, it should be fairly easy.

Agree, but it might be worth the effort to have a look at emulation the
interrupt logic too, if it's not too much trouble.

Afaik the interrupt logic is only used in one place in the CBM-II
series and nowhere else, so if we are short on cells in some kind of
programmable logic it might be okay to just emulate enough to make the
CBM-II work with the existing kernal, if that even can save something.

(It would probably be a saving to hard code the replacements as 6523's
or 6525 with interrupt controller always enabled).

--
(\_/) Copy the bunny to your mails to help
(O.o) him achieve world domination.
(> <) Come join the dark side.
/_|_\ We have cookies.

[smf]

On 26/06/2018 05:46, Steve Gray wrote:
> It looks like we CAN'T replace the 64Kx1 drams with 64Kx8 due to the method used by the EF chip to select individual bits.

You could use faster ram and perform a read, insert the bit and then
write back the modified byte. You'd probably want to store each plane in
a 64kx8 dram though, so you'd need 3 copies of that logic.

When outputting you get 8 pixels for each memory read & with this scheme
you'd continue to do so, if instead you use the extra bits in the ram
chip for individual planes then you'll need memory that is 8 times faster.

[smf]

On 26/06/2018 05:52, vossi wrote:
> A problem is the 6523 - Its very hard to find.
> It is only available from mos!

The EF9365 is only available from thomson.

I'd be tempted to try to build one that is 1:1 based on the schematic,
write software for it and then if there is demand for more then just use
a cpld/fpga containing everything.

[Gerrit Heitsch]

On 06/26/2018 06:52 AM, vossi wrote:
> A problem is the 6523 - Its very hard to find.
> It is only available from mos!

Anyone have a datasheet for the 6523? I still think it might be possible
to use 2 6522 plus some extra logic to recreate the register map of a 6523.

  Gerrit

[smf]

http://archive.6502.org/datasheets/mos_6523_tpi_preliminary.pdf

On 26/06/2018 15:59, Gerrit Heitsch wrote:

> On 06/26/2018 06:52 AM, vossi wrote:
>> A problem is the 6523 - Its very hard to find.
>> It is only available from mos!
>
> Anyone have a datasheet for the 6523? I still think it might be
> possible to use 2 6522 plus some extra logic to recreate the register
> map of a 6523.
>
>  Gerrit
>
>

[Gerrit Heitsch]

On 06/26/2018 06:05 PM, smf wrote:

> http://archive.6502.org/datasheets/mos_6523_tpi_preliminary.pdf
>
> On 26/06/2018 15:59, Gerrit Heitsch wrote:
>> On 06/26/2018 06:52 AM, vossi wrote:
>>> A problem is the 6523 - Its very hard to find.
>>> It is only available from mos!
>>
>> Anyone have a datasheet for the 6523? I still think it might be
>> possible to use 2 6522 plus some extra logic to recreate the register
>> map of a 6523.
>>
>>  Gerrit
>>
>>
>

Ok, so the 6523 is just 3 direction registers and 3 data registers. That
should be possible with two 6522 and some logic that adjusts the /CS and
RS signals for them properly.

  Gerrit

[Jim Brain]

On 6/26/2018 4:24 AM, Michał Pleban wrote:

vossi wrote:

A problem is the 6523 - Its very hard to find.
It is only available from mos!

I suppose it's time somebody built a replacement :-) Without the
interrupt logic of the 6525, it should be fairly easy.

Regards,
Michau.

I'll upload an untested 6523 Verilog implementation this evening.  I was working on it for you and Rob, but have not tested it.  Maybe someone else can get to it before me.

Jim

[Steve Gray]

The schematic says 6523 or 6525. Can you not replace these with the D8255 chip like was done on the 8088 card?

I agree, we should clone it first then modify.

Steve

---

From: smf <[hidden email]>
To: [hidden email]
Sent: Tuesday, June 26, 2018 8:01 AM
Subject: Re: New CBM-II discoveries

On 26/06/2018 05:52, vossi wrote:

> A problem is the 6523 - Its very hard to find.
> It is only available from mos!

The EF9365 is only available from thomson.

I'd be tempted to try to build one that is 1:1 based on the schematic,
write software for it and then if there is demand for more then just use
a cpld/fpga containing everything.

[smf]

On 26/06/2018 19:55, Steve Gray wrote:
> The schematic says 6523 or 6525. Can you not replace these with the D8255 chip like was done on the 8088 card?

I dislike that idea because disk loaded software can't access the
hardware directly unless it supports both the 8255 and 6523.

I'd prefer to see the 8088 card changed back.

[Michał Pleban]

Hello!

smf wrote:

> I dislike that idea because disk loaded software can't access the
> hardware directly unless it supports both the 8255 and 6523.
> I'd prefer to see the 8088 card changed back.

Why? No disk loaded software accesses the 6523 or 8255 on the 8088 card.
It is only accessed by the card's BIOS, which is modified appropriately
to work with original disk-loaded software (tested with MS-DOS 1.25 and
CP/M 1.1).

Regards,
Michau.