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Curt Vendel

7800 Expansion Module

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Hey guys! Aside from programmers, how would this be of interest to the "average" 7800 user?

 

Thanks!!!

 

AdeptRapier

 

:)

For a person that is not a programmer like myself, this would be an interest due to the following reasons:

 

1.) Programmers can program games on Atari 7800 Expansion Module that would be difficult to do without an expansion module.

 

That means an "Average" 7800 user wouldn't be able to have a chance to play or buy some future Atari 7800 games without having an Atari 7800 Expansion Module.

.

2.) Pokey in Expansion Module means gamers don't have to pay extra with a cartridge with a Pokey sound chip. Beef Drop is proof of a game that cost more with a Pokey sound chip.

 

3.) Gamers don't have to complain about "future homebrew releases" sounding as bad as Donkey Kong for an example.

Edited by 8th lutz

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Answers:

 

1. Any game that is coded to work with the High Score Cart

2. Better sound for any games that are programmed to use the Pokey

3. More memory support for larger potential future programs, I/O lines for potential future keyboards, use of XL computer peripherals and so forth - if programmed.

 

Curt

 

So in non-pin/slot/jumper/eprom/ram terms does this mean:

 

1. The ability to save our score for -any- game?

2. Better sound for -all- games?

3. Other? (Simple terms)

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That should'nt be affected, only the RF interface would be affected by the increased square wave activity on the system bus.

 

 

Curt

 

My only concern is that once you start connecting keyboard lines and SIO lines to this and channeling it through the cartridge slot, that thing is going to generate some really nasty RFI which might in the end, make the video signal from the 7800 look really choppy.

 

Even with an A/V mod?

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BTW - this is what I am proposing (the piggyback module, not the keyboard), I have the mechanicals for this and have been talking with the original Atari ID designer who created it so recreating the original plastics will not be an issue.

 

 

 

post-23-1244918023.jpg

 

 

Curt

 

 

 

That should'nt be affected, only the RF interface would be affected by the increased square wave activity on the system bus.

 

 

Curt

 

My only concern is that once you start connecting keyboard lines and SIO lines to this and channeling it through the cartridge slot, that thing is going to generate some really nasty RFI which might in the end, make the video signal from the 7800 look really choppy.

 

Even with an A/V mod?

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So this would just be a box that plugs into the I/O port that would have an SIO connector and some kind of keyboard connector on it plus a number of things built into such as more RAM, High-score 'cart', Pokey, etc? With the picture I'm now a little confused where this box would connect to. My first impression was that it would be inside the 7800 but now I'm confused.

 

Allan

 

 

BTW - this is what I am proposing (the piggyback module, not the keyboard), I have the mechanicals for this and have been talking with the original Atari ID designer who created it so recreating the original plastics will not be an issue.

 

 

 

post-23-1244918023.jpg

 

 

Curt

 

 

 

That should'nt be affected, only the RF interface would be affected by the increased square wave activity on the system bus.

 

 

Curt

 

My only concern is that once you start connecting keyboard lines and SIO lines to this and channeling it through the cartridge slot, that thing is going to generate some really nasty RFI which might in the end, make the video signal from the 7800 look really choppy.

 

Even with an A/V mod?

Edited by Allan

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So this would just be a box that plugs into the I/O port that would have an SIO connector and some kind of keyboard connector on it plus a number of things built into such as more RAM, High-score 'cart', Pokey, etc?

Look closer at the picture (see the outline of the 7800 beneath it). Looks like it would be expensiveish to make though.

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Hey guys! Aside from programmers, how would this be of interest to the "average" 7800 user?

 

Thanks!!!

 

AdeptRapier

 

:)

For a person that is not a programmer like myself, this would be an interest due to the following reasons:

 

1.) Programmers can program games on Atari 7800 Expansion Module that would be difficult to do without an expansion module.

 

That means an "Average" 7800 user wouldn't be able to have a chance to play or buy some future Atari 7800 games without having an Atari 7800 Expansion Module.

.

2.) Pokey in Expansion Module means gamers don't have to pay extra with a cartridge with a Pokey sound chip. Beef Drop is proof of a game that cost more with a Pokey sound chip.

 

3.) Gamers don't have to complain about "future homebrew releases" sounding as bad as Donkey Kong for an example.

 

Hi!

 

Thanks for the answers! So if I understand this correctly, a game that would output sound for the Pokey would automatically "know" that this thing is plugged in? In otherwords, my copy of "Beef Drop" would work with one of these without me having to buy a different version that is specially coded for the expansion module?

 

Also,

 

This is my personal "take" on the whole "expansion module thing". I have always had real love/hate feelings towards things like this. On the one hand, it sounds cool and everything, but on the other hand I would sure hate to see an expensive add-on that "kills' the "unexpanded 7800" homebrew scene. I mean, if this thing turns out to be great and everyone who programs the homebrews ONLY programs games for the "expanded" 7800, then that sort of sucks for the rest of the 7800 users.

 

Anyways, that's just my 2 cents..hopefully "if" the expansion thing happens it doesn't prompt all the homebrew programmers into ONLY supporting it with their games.

 

Adept Rapier

 

:)

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With the Pokey you could conceivable interface a keyboard to it, you could also interface Atari SIO devices -- you'll have to address the pokey of course. As for controller ports, why would you need more then 2 ?

 

 

Curt

 

I do have a question. Could that module support additional controller ports?

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You sir win a cookie! Yes, the HSC would be built into it, that was actually how the whole thing started originally, adding the memory and pokey just seemed a logical approach.

 

 

Curt

 

So do I read correct that the expansion module will have a HSC built in it?

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The plastics are the only costly part to it. If I could keep the price down to around $99-$119 and do 500 or so units I could recoup the plastics tooling cost.

 

 

 

Curt

 

 

So this would just be a box that plugs into the I/O port that would have an SIO connector and some kind of keyboard connector on it plus a number of things built into such as more RAM, High-score 'cart', Pokey, etc?

Look closer at the picture (see the outline of the 7800 beneath it). Looks like it would be expensiveish to make though.

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You bring up some very good points Adept...

 

However, at some point every must ask themselves - do we want to take the console further and really push its capabilities?

 

The HSC functionality... any game will work whether it see's an HSC plugged in or not, so that is a non-issue.

I know Ballblazer MUST see a Pokey to work, however games like Commando don't, I can't speak for Beef Drop and whether it requires a Pokey to work or not....

 

However, if coders are prudent enough to code their games to have a simple routine to look for a feature (high score cart, or Pokey) then flag a variable on to make use of that enhancement when present, otherwise run normally without it, then that clears the games and the players from being required to have to have such a device.

 

You could squeeze a 2K, maybe even an 8k SRAM into a cartridge and give it onboard memory for more expanded game designs, this increases the per unit cost of course, but the buyer - whether they bought that game or the expansion module would have to outlay the cash for the enhanced gameplay, with the expansion module - the cost would be a one time expense and if enough games came out that now needed added memory then that expense would be further absorbed, its just a matter of the games being written and how many - that is all a guess of course.

 

 

Curt

 

Hey guys! Aside from programmers, how would this be of interest to the "average" 7800 user?

 

Thanks!!!

 

AdeptRapier

 

:)

For a person that is not a programmer like myself, this would be an interest due to the following reasons:

 

1.) Programmers can program games on Atari 7800 Expansion Module that would be difficult to do without an expansion module.

 

That means an "Average" 7800 user wouldn't be able to have a chance to play or buy some future Atari 7800 games without having an Atari 7800 Expansion Module.

.

2.) Pokey in Expansion Module means gamers don't have to pay extra with a cartridge with a Pokey sound chip. Beef Drop is proof of a game that cost more with a Pokey sound chip.

 

3.) Gamers don't have to complain about "future homebrew releases" sounding as bad as Donkey Kong for an example.

 

Hi!

 

Thanks for the answers! So if I understand this correctly, a game that would output sound for the Pokey would automatically "know" that this thing is plugged in? In otherwords, my copy of "Beef Drop" would work with one of these without me having to buy a different version that is specially coded for the expansion module?

 

Also,

 

This is my personal "take" on the whole "expansion module thing". I have always had real love/hate feelings towards things like this. On the one hand, it sounds cool and everything, but on the other hand I would sure hate to see an expensive add-on that "kills' the "unexpanded 7800" homebrew scene. I mean, if this thing turns out to be great and everyone who programs the homebrews ONLY programs games for the "expanded" 7800, then that sort of sucks for the rest of the 7800 users.

 

Anyways, that's just my 2 cents..hopefully "if" the expansion thing happens it doesn't prompt all the homebrew programmers into ONLY supporting it with their games.

 

Adept Rapier

 

:)

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I gotta run, but one last comment for today...

 

Since the module would have a lot of potential, if I put footprints and plastic knockouts to accomodate an SIO connector and a DB9 or DB15 connector (for a potential future keyboard add-on) onto the pcb and behind each, put a grid of through holes for doing prototyping and perhaps leave an open sock footprint for potential mcu like a PIC, AVR or even a 8048 perhaps, putting in some future proofing to the design... however I don't want to go overboard, it may also be prudent to put a footprint for a standard wall wart type power connector on the pcb with a jumper select for internal/external power...

 

Having all these additional chips and discrete logic is going to add a lot of additional load to the 7800 P/S and I don't want to create an overheat issue with the 7805 regulator or the actual 7800 Power supply itself...

 

Which reminds me, if I never mentioned this, here is a tip for anyone with a 7800 power supply that has died...

 

The Atari Lynx a/c power adapters (9vdc 1a) are the same and if you cut off the connectors and swap them, you can make a Lynx p/s into a 7800 p/s

 

 

 

Curt

Edited by Curt Vendel

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I'm not sure why it would have any such limitation. Maybe it's too slow for the Maria structures, but I doubt it. It's a modern surface mounted 128KB SRAM chip so I assume it's at least as fast as the 80's RAM in the console.

 

That all might be true but if I remember correctly(as it was a while ago),I asked the developer of the unit if it could use

the extra as Maria ram and I believe he told me it was to emulte ROM only. Perhaps he did not hookup the write line

to the 7800.

 

Of course the RAM is bankswitched in a 16KB window, so the Maria wouldn't be able to see any more than that at once.

I have an XBoard but haven't been able to experiment with it yet, as I can't seem to get it to work. I'll probably post a thread about that when I get things more organized.

 

Right now you only have 4k. 16k ram would be absolutely wonderful if Maria could access it..

Remeber now, Maria does not use a ram buffer for its screen but instead draws each scanline

from a dll. However, using very large sprites one could very well use a few to build a 'screen

buffer'. I've already done this using an emulator, but unfortunately, A ) you can't really trust

an emulator and B ) I had to use ROM space as that was all the emulator would allow for. As

I said, you can't really trust what an emulator is doing.

 

This was using MESS btw. I have the ProSystem but still do not know how to tell it to make use

of that extra space a a RAM expansion. Once I figure this out, I can get back to coding Warbirds.

I will change that name eventually.

Edited by Gorf

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1. Any game that is coded to work with the High Score Cart

2. Better sound for any games that are programmed to use the Pokey

3. More memory support for larger potential future programs, I/O lines for potential future keyboards, use of XL computer peripherals and so forth - if programmed.

 

But again....will Maria be allowed access to the extended RAM? Did not see an answer to that...or did I miss it?

Edited by Gorf

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But again....will Maria be allowed access to the extended RAM? Did not see an answer to that...or did I miss it?

 

Maria would see ALL ram as rom iirc in that it does nothing but look up it's DLs and DLL and read what it points to. Odds are it would be able to see the extended RAM just fine, but since it'll do nothing but read, it's effectively "rom". Perhaps that's what they meant?

 

 

*additionally*

 

Besides which, there'd be no point of having the RAM there at all if it couldn't be accessed by either of the CPUs. (Sally or Maria)

And both of them see the exact same address space, so I can only assume that the RAM would be accessible. You likely won't be able to read DLs or DLLs off of it directly since those have to be in main ram due to speed issues iirc. But that doesn't stop you from building the DLs etc out there anyway and then copying them into main ram. (or outsourcing all non-DL info to the external ram to have space on main ram for the DLs.)

 

Either way, having 16k of ram to hold editable graphic data would probably simplify the DL construction somewhat.

Edited by Mord

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Now to address this directly. ;)

 

However, instead of a computer CPU this would be an expansion module, so far I will commit to the design the following features:

 

1. Built in High Score Cartridge capability (thanks to Pacmanplus and others, more and more games are now HSC enabled making this a more valuable feature to the system as a whole)

2. A 16K RAM upgrade

3. A Pokey Chip

 

The module is fairly roomy relatively speaking and there would be room for say an extra eprom and supporting discrete logic to have a built in game as well which would be over ridden when a cartridge was inserted a top of it.

 

Having all that would be awesome. For comments/other ideas:

 

1. Definitely make sure it's possible to test for the presence of the pokey so programmers will be able to use it, or fall back on alternate methods if it's not found.

 

2. If a built-in game is made, obviously it'll have to try to take full use of the expansion port's abilities!

 

3. Having an external port added for potential keyboard support in the future would be great, but perhaps another port that'll fit an Atarivox would be a good idea? Might be an idea to go for a customized atarivox version for the 7800 if that ends up happening, to allow the speakjet's sound get mixed in properly with the pokey etc. This could be used for save states etc possibly on the 7800.

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Atarivox already connects to a 2600, or 7800 through the 2nd joystick port.

 

 

Curt

 

Now to address this directly. ;)

 

However, instead of a computer CPU this would be an expansion module, so far I will commit to the design the following features:

 

1. Built in High Score Cartridge capability (thanks to Pacmanplus and others, more and more games are now HSC enabled making this a more valuable feature to the system as a whole)

2. A 16K RAM upgrade

3. A Pokey Chip

 

The module is fairly roomy relatively speaking and there would be room for say an extra eprom and supporting discrete logic to have a built in game as well which would be over ridden when a cartridge was inserted a top of it.

 

Having all that would be awesome. For comments/other ideas:

 

1. Definitely make sure it's possible to test for the presence of the pokey so programmers will be able to use it, or fall back on alternate methods if it's not found.

 

2. If a built-in game is made, obviously it'll have to try to take full use of the expansion port's abilities!

 

3. Having an external port added for potential keyboard support in the future would be great, but perhaps another port that'll fit an Atarivox would be a good idea? Might be an idea to go for a customized atarivox version for the 7800 if that ends up happening, to allow the speakjet's sound get mixed in properly with the pokey etc. This could be used for save states etc possibly on the 7800.

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Atarivox already connects to a 2600, or 7800 through the 2nd joystick port.

 

 

That it does - eating up the second controller port in the process for two player games and forcing the use of external speakers to use the speakjet. Two things that could be improved on potentially. :) But it's just food for thought.

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So this would just be a box that plugs into the I/O port that would have an SIO connector and some kind of keyboard connector on it plus a number of things built into such as more RAM, High-score 'cart', Pokey, etc?

Look closer at the picture (see the outline of the 7800 beneath it). Looks like it would be expensiveish to make though.

Oh, Dua. Thanks, Kenfused.

 

Allan

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Atarivox already connects to a 2600, or 7800 through the 2nd joystick port.

 

 

That it does - eating up the second controller port in the process for two player games and forcing the use of external speakers to use the speakjet. Two things that could be improved on potentially. :) But it's just food for thought.

 

This is why brought the idea for the extra controller ports.

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The expansion module sounds like a great idea, Curt! I'm finally looking into 7800 development again myself after a long absence, and I've been having a little trouble lately with my HSC, so this would be the perfect solution. Having that and the POKEY/RAM functionality of the (apparently) stillborn XBoarD would be enough for me, so whether you decide to add additional features or not, definitely count me in for two or three units!

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That expansion module looks pretty cool. I like how it looks like a miniature 7800, although I was hoping it would be a little more flush to the 7800. When can we expect to see the finished product?

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That expansion module looks pretty cool. I like how it looks like a miniature 7800, although I was hoping it would be a little more flush to the 7800. When can we expect to see the finished product?

That's an excellent point! It gave me a flash-- how about a kit with just the innards with it so I or someone like me can do a custom case without sacrificing an original? Is this a tall order that may never happen??

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