New Personality Board for the A800

[santosp]

A few months ago a good friend here from AA sent me an Atari 800 NTSC in excellent condition. Before he left there I asked him to find (at my expense) the personality and processor boards in the PAL edition. So it happened.

 

After its arrival here and the change of the necessary components for its operation in a PAL system, I started to notice some weaknesses.

 

First of all on the personality board. If someone wanted to change or add another OS or MATH, it was almost impossible due to the hard-to-find customized roms, in hardware level also. 2* CS on ic for the OS roms and 3*CS on ic for the MATH rom.

In my case I wanted initially to change the OSA to OSB, but after I was wonder why not be possible to add fast math rom or complementary OS's like Omnimon etc.

 

Secondly, the problem regarding someone to have expansion memory. If someone wants to add one of the existing older (hard to find-expensive) implementations or even the newer ones, they should definitely have at least two from the original pcb memories from Atari. In my case this was not a problem, but then another thought came to my mind. Back then, all expansion memory manufacturers built their implementations using dynamic RAM, the only memory chip available at the time. Today, however, static memory has prevailed, so today's implementations are all done with it. I don't like the idea that my Atari will work having a mix of these, although many will say that there is no problem with their computer's operation. I'm just stating my opinion.

 

Third, searching on web I came across a implementation of hard disk for the A800 by Mr. Atari. Yes, he had made a unique such object back then 14 years ago! I really couldn't believe my eyes, since until then I thought that something like this was possible only for the next Atari series. On the other hand, no mention anywhere if it works and how or not, as opposed to MyIDE Internal designed for the next generations XL/XE

 

Somewhere there I got the idea if it is possible to build a board that includes all the above, with the smallest possible cost, and a necessary condition that the user does not need to make the slightest modification to his Atari. Not even a simple cable!

 

As it is understood, in order to do this, I would have to fully simulate all the functions of the personality board. It seemed huge. I initially asked ClausB for help regarding the implementation of main memory using static memory. He sent me a drawing which helped me very from enough.

 

Then I read somewhere about the operation of the 48/52K and at first I tried to implement it without success, but also without understanding that this is due to the existense of the two buffers which control the data bits between CPU the memory and the peripheral ic's. Something that exist only in the A800 not the A400.

 

Then it was time for the extra memory. There I found that some other member had successfully made an implementation of ATHLON using static memory. I decided to follow it. Although it was easy to change the logic to have 1024KB, the 512k was enough for me.

 

Finally, I implemented the MyIDE internal using of course the Clue rom version. Today's needs require the use of a CF card of course, so that happened. I was very stressed about to finding a correct schematic for the IDE to CF conversion. Finally, after reading a lot on web, I think I succeeded.

 

Well, I was fine with everything above, but until that time I had in my mind that any option settings would be made with dip switches. Kind of annoying don't you think? When I got to the end I wondered if this could be done electronically? Of course, this would require the existence of some program to be able to handle it.

The issue was that there was a big problem. The CPLD's are passive components and do not have internal memory so that someone can save registers.

With the help of the same friend who had sent me the Atari and we were collaborating from the beginning on this project, a new idea was born. The use of a tiny microcontroller (8 pins) just for this function. That is, it would store the registers when asked to do that and would return them to the CPLD permanently in the same order every time the Atari was started.

 

After many tests and thanks to him in this we succeeded. It was really the most difficult piece that I implemented in the architecture of CPLD.

So now someone can preset the following functions of this board by loading an executable .xex file almost instantly.

 

1. 48/52K Base Memory (Selectable)

2. 512KB AXLON Memory (Enable / Disable)

3. 1 to 8 OS's and Maths (Selectables)

 

 

In case someone wonders about any of the following, I hope that these answers to cover him.

 

Q. Can I install it on an A400?

A. No because there is no way to avoid the Atari modification.

 

Q. Can the change of OS's and Maths in the 8 free positions be done by writing to these through the Atari?

A. No, because I'm not a programmer, nor do I have the know-how and maybe free space/pins in the CPLD to do it.

 

Q. Would not be more convenient someone to call the routine of changing the settings from within the Atari during boot by pressing a key, than to need to load a .xex file?

A. Even though I have except the 8 slots and 1 extra MBit available, I haven't been able to "catch" an "Non Maskable Interupt" key and a reboot after that in order to lock the rom in address A17, so that it is possible to load the routine from there.

 

Q. I see places for components for RTC circuit implementation on the back of the board.

 

A. I actually added it as a last minute thing. It is based on THE logic designed by tf-hh member here. Although I don't have the required ic to test it, yes it could work. The issue is how useful something like this is, since most current implementations of SDX have it built in.

 

Q. Can I bought one?

 

A. I have only some few pcb's here available. If we come to an agree between us I can assemble one for you.

Why not more from that? Because with the other beast (Incognito) out there I am sure that not many interestsed on this.

At the end was a great experience for me as to where can someone to arrive...

 

I would like to thanks as I did on the pcb for their designs or ideas the below members in alphabetical order.

 

ClausB

Mr.Atari

panther (Special thank note on the pcb)

retrocanada76

tf-hh

 

 

Pictures

[Mclaneinc]

It's not for me, but congratulations on updating this old hardware, you devs keep this hobby ticking over with innovation and group mentality.

 

Be it software or hardware, it's all great..

 

Thank you..

[TGB1718]

Very nice job ?

[Britishcar]

Very interested. Please PM me or point me to another location with more detail. Thank you.

[reifsnyderb]

Very nice!  I like that you don't have to modify the Atari 800.

Edited July 11, 2022 by reifsnyderb

[santosp]

1 hour ago, Britishcar said:

Very interested. Please PM me or point me to another location with more detail. Thank you.

Hi Britishcar, thank you for the interest.

 

Right now the only I have to show about the implementation is on this page.

As I said, this is a build for someone who has a working A800, and would like to have on a Personality card, the 48/52K, 512K Ahlon, 8 OS & Maths, and the early implementation of MyIDE internal(special written for A800). All the above proven works well, and at this moment any settings on the board are done by an external executable .xex file written by a member here the "panther".

 

The second small pcb which look in the pictures, is for the extra signals who need on this project to work. It placed in the memory slot 2 and send in the main pcb the D0 till D7 memory data signals, R/W_L, A13, S2 and S3.

What is forgot to say in my first post is that the main pcb feed all the points which previously have the "RAS" signal with the more compatible "PHI2" signal. So the known modification below the Cartridge slots isn't needed anymore.

 

Regarding the OS's, you will need to tell me in advance what you want so that I can write them in the eeprom. But if you need to write something new, you will need to have access to an external programmer. I can help on this giving the necessary information regarding addresses in the eeprom etc.

 

Additionally, anyone more experienced than me in the field who would like to participate in, let's say in a compatibility test of this board, I will gladly accept their suggestions regarding what additional software to I test.

 

The cost for one of these assembled is 50 euro plus shipping. Due to the known lack of components worldwide, with difficulty I have only managed to have stock for a total of 4 of them, of which two are already reserved by me and the panther.

[santosp]

An update.

Omniview and Omnimon now can run on this board as roms in any empty place.

I did the needed modifications and now the board can handle the rom content at the needed address locations C000-CFFF as to work with these.

[sup8pdct]

There are no atari PAL osB roms. There is one Some one did kicking round on these pages somewhere I think should pass salt version check.

 

James

[santosp]

Control menu picture. An option thanks to the member panther. ?

 

 

[+KlasO]

On 7/14/2022 at 9:22 AM, sup8pdct said:

There are no atari PAL osB roms. There is one Some one did kicking round on these pages somewhere I think should pass salt version check.

 

James

Not sure if I'm misreading this, but I have a PAL 800 and I fairly sure that is has OSB.

[sup8pdct]

Dump and upload. Quick check is the part numbers printed on the roms . Please quote what they are.

 

James

[+KlasO]

7 hours ago, sup8pdct said:

Dump and upload. Quick check is the part numbers printed on the roms . Please quote what they are.

 

James

It's stored in a box, not exactly inaccessible but might take a few days before I can do this. 

[+KlasO]

On 7/20/2022 at 7:39 PM, KlasO said:

It's stored in a box, not exactly inaccessible but might take a few days before I can do this. 

I checked the 800 but it was OS A. Sorry for getting anyone's hopes up.

[sup8pdct]

18 hours ago, KlasO said:

I checked the 800 but it was OS A. Sorry for getting anyone's hopes up.

I threw a celebration party, much dancing and drinking.......?

Now i have to say sorry to all who attended.... ??   ?

[santosp]

Thanks to panther!?

 

 

Edited July 28, 2022 by santosp

[reifsnyderb]

Does the CF card work?  Also, does this personality board have a delay line for WRITIME and a RASTIME output?

 

[santosp]

@reifsnyderb

1. Yes exact as described here, except from the images. I don't know how to do these although I can see the initial load page if I choose it. . Therefore as it is now after you select the dedicated OS of Mr. Atari from the selection menu, and you have the CF placed in slot,  Atari boots directly to DOS. From there I can copy/load DOS and .xex files. 

 

2.In the RASTIME I have pass directly the PHI2 signal so the new user no need to do the well known modd on its Atari!

 

3. Why you need this 2ms delay line? Do you have any program in mind that needs this delay so to I check for incompatibility?

[reifsnyderb]

5 minutes ago, santosp said:

@reifsnyderb

1. Yes exact as described here, except from the images. I don't know how to do these although I can see the initial load page if I choose it. . Therefore as it is now after you select the dedicated OS of Mr. Atari from the selection menu, and you have the CF placed in slot,  Atari boots directly to DOS. From there I can copy/load DOS and .xex files. 

Very nice.  Good schematic, too.

 

5 minutes ago, santosp said:

2.In the RASTIME I have pass directly the PHI2 signal so the new user no need to do the well known modd on its Atari!

 

Makes sense.

 

5 minutes ago, santosp said:

 

3. Why you need this 2ms delay line? Do you have any program in mind that needs this delay so to I check for incompatibility?

Since you are replacing all of the normal RAM cards you probably don't need it.  I was just curious as I didn't see anything on the board pictures that looked like the delay line.

 

 

Also I am curious as to if there any thought about using an SD card as opposed to the CF card and/or why the CF card was chosen?

 

Either way, it looks like a great board!  Are you going to make more of them?

 

[santosp]

Just now, reifsnyderb said:

Also I am curious as to if there any thought about using an SD card as opposed to the CF card and/or why the CF card was chosen?

 

Either way, it looks like a great board!  Are you going to make more of them?

I don't have the technical training to do something like this on my own. So I was use the schematic as exact I found it. It work flawlessly,  just it disappointing because I thought that others will had made it also, (even in more simple implementations), so I would have found some more information. In reality, even its inventor has forgotten that he made it! He actually did it once,  many years ago! 

 

I have some pcb's rest but not assembled.
I did it just to prove to myself that I can do it. Not for sales.
The bet was if a construction could be made with the smallest cost, the available components at this time in the middle of worldwide electronic crisis and without any modification on the part of the user.
Plug and play.

 

I inspired and used in my board by your small pcb (jumper board) the outline design! It is so clever indeed. ?

[reifsnyderb]

30 minutes ago, santosp said:

I don't have the technical training to do something like this on my own. So I was use the schematic as exact I found it. It work flawlessly,  just it disappointing because I thought that others will had made it also, (even in more simple implementations), so I would have found some more information. In reality, even its inventor has forgotten that he made it! He actually did it once,  many years ago! 

 

I have some pcb's rest but not assembled.
I did it just to prove to myself that I can do it. Not for sales.
The bet was if a construction could be made with the smallest cost, the available components at this time in the middle of worldwide electronic crisis and without any modification on the part of the user.
Plug and play.

 

I inspired and used in my board by your small pcb (jumper board) the outline design! It is so clever indeed. ?

That jumper board does look familiar.    ?

 

Your thread got my interest because I was trying to do an upgrade board to add BASIC to it as well as add some other features.  I came to the conclusion that other board slots would have to be used then set the idea aside.  Every now and then I look over the idea and see if I can get any farther along.  I'd love to be able to change my 800's so that without any modifications, and by only swapping boards, that they would act more like an XL with BASIC coming up instead of the memo pad and have plenty of extended memory.  One problem was that I didn't know that my burner could flash modern flash rom chips.  So I had no idea how to make the ROMs with this chip shortage.  You have some of the features I was looking for.   ?

 

 

[Panther]

Adding cartridges wouldn't be difficult at all...Panos, next version!  ?

[reifsnyderb]

@santosp:  Does your board handle the /exsel signal from RAM slot 3?

 

Edited July 29, 2022 by reifsnyderb

[santosp]

You mean if produce the !exsel signal to feed the RAM slot 3?!

Yes it produce it.

 

 

Edited July 30, 2022 by santosp

[santosp]

18 hours ago, santosp said:

You mean if produce the !exsel signal to feed the RAM slot 3?!

Yes it produce it.

 

 

Anyway, it's very strange!

Although I have read and elsewhere that the specific signal is an input with the purpose of doing what it does when it goes in low state, in the Atari schematics it appears as an output that can control external hardware. Either through memory slot 3 or through the hidden expansion connector.

I'm just saying that I read in the plans from Atari!

In my pcb implementation it doing exact this, but is very easy for me to change the equation and this to be an input like the most people believe.

[reifsnyderb]

10 minutes ago, santosp said:

Anyway, it's very strange!

Although I have read and elsewhere that the specific signal is an input with the purpose of doing what it does when it goes in low state, in the Atari schematics it appears as an output that can control external hardware. Either through memory slot 3 or through the hidden expansion connector.

I'm just saying that I read in the plans from Atari!

In my pcb implementation it doing exact this, but is very easy for me to change the equation and this to be an input like the most people believe.

The way Atari has it's schematics it is deceiving.  The schematics show /Exsel as having an arrow pointing out.  This is incorrect.  But it's not the only mistake in the schematics.  (You should see all of the descriptive mistakes with the XL's PBI.   lol   )

 

From my interpretation of the schematics the /exsel is an input to the personality board.  /Exsel is normally held high by R402.  When /exsel is pulled low (grounded) by the logic of a board in RAM slot 3, the following happens:

 

1.  Pin 13 of Z403C is set low resulting in pin T on the personality board being set low.

2.  Pin 2 of Z402A is set low resulting in pin 15 on the personality board being set high.

3.  On the motherboard, both 74LS243's are set to disconnect the data bus from the personality board and everything "behind" it.  In addition to disconnecting the personality board, the cartridge slots, POKEY, and PIA are all disconnected from the data bus.

 

/exsel (and it's attached circuitry) is normally held high by  R402.  Also, Z403 is open collector output so that Z403 will only ground the outputs...R402 holds those outputs high.

 

Also, Atari has Pin 15 of the personality board mislabeled.  Pin 15 should be /GAB.  (I found this out by looking up the datasheet on a 74LS243.)