Atari 800 XL Remake

[reifsnyderb]

Hello,

 

This all started as a project to add chroma back to the Atari 800 XL main board. While I added it back and have the KiCad project for it, I figured I’d go a bit farther and “modernize” it a little. Reducing component count and removing/replacing special chips with a modern equivalent was also done. As with any project, feature creep became an issue as I decided to add support for many common upgrades so I looked through the comments on the Atari 130XE remake and added support for some mentioned upgrades.

 

Does anyone else have any thoughts as to anything else that would be helpful?  If there is anything I missed I'd like to add it before getting a board made.

 

If anyone knows the proper hole positions  and sizes to mount the Ultimate 1MB and Sophia that would be great!

 

Changes:

 

General:

1. Surface Mount Components where practical.

2. 4 layer circuit board. (Ground on second layer.)

3. Removed filtering components not present on 1088 XEL project.

4. Integrated JTAG connection for each ATF1502 CPLD.

5. Fewer components.

6. Atari chips required: GTIA, ANTIC, POKEY, OS ROM, & BASIC ROM.

 

Processor:

1. Uses W65C02S (Based off of circuitry by The Byte Attic.)

 

Memory:

1. 512kb SDRAM (Not all accessible...will depend upon banking strategy.)

2. Control circuitry replaced by ATF1502 CPLD.

3. PORTB bits 2,3,4,5, & 6 connected to ATF1502 CPLD for memory banking.

 

Memory Management Unit:

1. U2 and U3 replaced by ATF1502 CPLD.

 

Power:

1. Simplified power circuitry.

 

Video:

1. Chroma added to monitor port.

2. UAV support with jumpers and headers.

3. Video improvements based off of Robert de Boer’s Atari 600 XL S-video &

composite clean video upgrade.

4. If proper crystals are installed, switching between NTSC and PAL can be

accomplished with jumpers.

5. U20 socket and chip left as DIP so as to facilitate UAV upgrade.

 

Ultimate 1MB Upgrade:

1. Headers added for HLT, R/W, PHI2, & RST.

2. Socket available for MMU.

3. Jumper added to configure ATF1502 CPLD for Ultimate 1MB Upgrade

 

Simple Stereo:

1. Headers added for “Bell” and A4.

2. Capacitors moved so as to not interfere.

 

Concerns:

1. Mount points for Sophia? (How to mount and where?)

2. Mount points for Ultimate 1MB? (How to mount and where?)

 

 

Thanks!

 

 

[+MrFish]

1 hour ago, reifsnyderb said:

Does anyone else have any thoughts as to anything else that would be helpful?  If there is anything I missed I'd like to add it before getting a board made.

 

5 volt on PBI

 

[+kheller2]

Add 5v to pbi. 

[reifsnyderb]

18 minutes ago, MrFish said:

 

5 volt on PBI

 

Thanks!  I just added the 5VDC on pins 47 and 48 of the parallel bus.    ?

 

Edited November 10, 2021 by reifsnyderb

[adam242]

It would be pretty sweet to make all this fit into the smaller footprint of a 600XL... looks like there's plenty of open space on the board to allow for further size reduction.

 

Just saying..

[reifsnyderb]

41 minutes ago, adam242 said:

It would be pretty sweet to make all this fit into the smaller footprint of a 600XL... looks like there's plenty of open space on the board to allow for further size reduction.

 

Just saying..

I think it would work nicely.  More space can be saved by soldering the CPLD's directly to the board and not using sockets for them.  

[reifsnyderb]

I was looking through DigiKey for connectors, such as the power connector, and couldn't find one with the original footprint.  I am thinking it would be a good idea, where possible, to replace the connectors with modern variants that fit the original cable with the same pinouts.  (Some, such as the SIO, aren't possible...of course.)

 

[Sugarland]

Looks very nice!! Yes can it be made to fit both cases?  Seems that the joystick ports on them are different distances from the back of the board, however the board could be made with ports in both locations for each respective case...?

[reifsnyderb]

8 hours ago, Sugarland said:

Looks very nice!! Yes can it be made to fit both cases?  Seems that the joystick ports on them are different distances from the back of the board, however the board could be made with ports in both locations for each respective case...?

That's an awesome idea!  I was just looking at pictures of both the 800xl board and 600xl board and found a picture comparing the backs of the machines.  (http://dunfield.classiccmp.org/atarixl/h/back.jpg)  Having 2 locations for joystick ports would be possible if there wasn't any serious conflicts between the holes.  But the SIO and parallel ports are also at different locations.  With the parallel port conflict I'd say the answer would be no, unless the parallel port were to be omitted.  Then it would be a "maybe" as more work would need to be done to see if everything else could be made to match up.

[+ZuluGula]

You could add second keyboard connector. More people design new, mechanical keyboards with FFC ribbon cable.

 

[+kheller2]

I'm waiting for the 1200XL remake thread!

 

[reifsnyderb]

25 minutes ago, ZuluGula said:

You could add second keyboard connector. More people design new, mechanical keyboards with FFC ribbon cable.

 

 

 

That would help to add an option for another connector that isn't available.  I think one of these could be added easily:

 

https://www.digikey.com/en/products/detail/molex/0528082470/3263053

 

 

 

[reifsnyderb]

8 minutes ago, kheller2 said:

I'm waiting for the 1200XL remake thread!

 

That would be cool.  Once the 800XL is working it would be just a matter of making up another board with minor modifications to the schematic.  (The same could be done for the 600XL, too.)  Currently I have access to an Atari 2600, 5200, 800, and 800XL.

[mimo]

13 hours ago, reifsnyderb said:

Concerns:

1. Mount points for Sophia? (How to mount and where?)

Sophia2 just replaces the gtia chip, so as long as you have enough space around it (which it looks like you do) then no problems

[reifsnyderb]

12 minutes ago, mimo said:

Sophia2 just replaces the gtia chip, so as long as you have enough space around it (which it looks like you do) then no problems

I was looking at this article:   https://en.devzine.pl/2019/09/23/how-to-upgrade-your-atari-with-ultimate-1mb-stereo-and-sophia-dvi/

 

On #6, he mentions making a "stand" using header pins to mount Sophia2.  Is this normal?  Should holes be added?

 

Thanks!

 

[+ZuluGula]

Sophia has separate board with DVI connector that replaces modulator. You could skip it and place the DVI connector directly on your pcb with matching connector to the Sophia board.

 

If you ever decide to make version for every Atari 8 bit case (maybe with exception for 400/800), why don't make the design modular? One common pcb with all Atari chips and another one with all the connectors that is specific for each XL and XE case.

 

Something similar to this project

 

 

Edited November 10, 2021 by ZuluGula

[_The Doctor__]

15 minutes ago, reifsnyderb said:

I was looking at this article:   https://en.devzine.pl/2019/09/23/how-to-upgrade-your-atari-with-ultimate-1mb-stereo-and-sophia-dvi/

 

On #6, he mentions making a "stand" using header pins to mount Sophia2.  Is this normal?  Should holes be added?

 

Thanks!

 

most of the issues are simple fraction of an inch/mm/whatever-unit-you-are-using interference by electrolytic cap etc. ever so slight movement or low profile alternatives on a new pcb would avoid the issues.... slight placement adjustments are all that are needed in most instances.

Edited November 10, 2021 by _The Doctor__

[tjlazer]

I was gonna say, make it 128K atleast!  That would be awesome to have 512k.

[mimo]

21 minutes ago, reifsnyderb said:

I was looking at this article:   https://en.devzine.pl/2019/09/23/how-to-upgrade-your-atari-with-ultimate-1mb-stereo-and-sophia-dvi/

 

On #6, he mentions making a "stand" using header pins to mount Sophia2.  Is this normal?  Should holes be added?

 

Thanks!

 

those are instructions for the older version of Sophia (Sophia DVI), the new one (Sophia 2) is much more compact and does not need any support

[+Spancho]

I don’t know if it is possible to cater additionally for a DIN13 at the same spot where the DIN5 for video sits.

That would be great for those running Sophia via RGB. You could run as well the DVI connections through the DIN13, so that there is no need to modify the case. Just a special adapter cable needed to get the DVI connector.

 

If not possible let’s have a DIN8 with the option to easily change the pin assignment via bridges.

 

just my thoughts.

[reifsnyderb]

5 minutes ago, Spancho said:

I don’t know if it is possible to cater additionally for a DIN13 at the same spot where the DIN5 for video sits.

That would be great for those running Sophia via RGB. You could run as well the DVI connections through the DIN13, so that there is no need to modify the case. Just a special adapter cable needed to get the DVI connector.

 

If not possible let’s have a DIN8 with the option to easily change the pin assignment via bridges.

 

just my thoughts.

The Atari DIN 5 and a DIN 8 don't have the same pin configuration, unfortunately.  (https://en.wikipedia.org/wiki/DIN_connector)  I'll check to see if a DIN 5 and DIN 8 uses a similar footprint so that either could be soldered in place.  I doubt a DIN13 would have a close enough footprint.  I do like the idea of avoiding case modifications.

[reifsnyderb]

1 hour ago, ZuluGula said:

Sophia has separate board with DVI connector that replaces modulator. You could skip it and place the DVI connector directly on your pcb with matching connector to the Sophia board.

 

If you ever decide to make version for every Atari 8 bit case (maybe with exception for 400/800), why don't make the design modular? One common pcb with all Atari chips and another one with all the connectors that is specific for each XL and XE case.

 

 

The modular idea is nice.  I am not sure how practical given space considerations, though.  I like the idea and will give it some thought.  The Atari 800 did have somewhat of a modular design....

 

I'll look into placing the DVI connector onto the board similar to the 130 XE remake project.

 

 

 

[reifsnyderb]

3 hours ago, ZuluGula said:

You could add second keyboard connector. More people design new, mechanical keyboards with FFC ribbon cable.

 

 

I just added a second keyboard connector.  Assuming I got the footprint right as the datasheet could have been a little better, it uses a Molex 0526102472 or similar.

 

 

 

[_The Doctor__]

The XE remake made perfect sense in that the XE machines have power path issues as well as poor quality thin traces... XL's don't have these issues. If it's just something to do that's cool. Many people can handle working on the XL's just fine but destroy their XE as soon as they touch it with an iron.

[+Spancho]

42 minutes ago, reifsnyderb said:

The Atari DIN 5 and a DIN 8 don't have the same pin configuration, unfortunately.  (https://en.wikipedia.org/wiki/DIN_connector)  I'll check to see if a DIN 5 and DIN 8 uses a similar footprint so that either could be soldered in place.  I doubt a DIN13 would have a close enough footprint.  I do like the idea of avoiding case modifications.

I think DIN8 shares the same 5 pins as DIN5.

DIN13 has nothing in common so that would be a change not compatible with the current connector.

But can be remedied with an adapter cable.

 

In my opinion, we should go the DIN13 route to avoid case modding to use the new fancy stuff easily preserving the cases.

I believe who ever builds himself this board can do as well the adapter cable.