29 replies to this topic

[Shaggy the Atarian]

Hello all! With the sponsorship of AtariAge, Atari7800.com, Jaguar Sector 2, and StaticGamer.com, I'd like to announce the Atari 7800 "Homebrewerpalooza" Contest. With this being the 20th year anniversary from when the 7800 was supposed to be released, it's time for more games to be made on the 7800!

The contest 'officially' begins tomorrow and ends on 6/5/05. Winners will be announced on June 27th, 2005.

Prizes include a 'Vader' ProLine joystick, and the winner will receive his game in cartridge form from AtariAge. They will also be able to have the title published by AA, like is done with 2600 and 5200 games now.

Here's a page you can visit to find out more if you're interested in participating in the contest.

http://www.staticgamer.com/modules.php?mod...ri_7800_contest

Good luck and have fun! :wink:

[Robert M]

I don't understand the reasoning behind this rule in the contest:

"File Size must not be smaller than 8kb. Anything above that that the 7800 can handle is fine. "

I mean, is it an emulator issue, or a manufacturing issue? Plus. are we penalized if our program is only 6K bytes and we pad the reamining 2K bytes with zeros?

Cheers!

[Shaggy the Atarian]

No the purpose was more to have slightly more to the games than what you can have on the 2600. But if you guys feel like that's a silly rule I'd be more than happy to change it. I'm more than willing to be flexible.

[Shaggy the Atarian]

OK, I've adjusted that little 'rule' there. As long as it can fit on a 7800 PCB, it's just fine.

[Cybergoth]

Hi there!

Sounds good to me. Except the trademark/copyright thing. Can't you change that into "use at own risk" or so?

Greetings,
Manuel

[Cybergoth]

Hi there!

Shaggy the Atarian said:

OK, I've adjusted that little 'rule' there. As long as it can fit on a 7800 PCB, it's just fine.

Ok, that raises another question about the specs of available PCB(s).
What are the recommended/available ROM sizes (and eventually supported BS schemes)?

Greetings,
Manuel

[Mitch]

Cybergoth said:

Hi there!

Shaggy the Atarian said:

OK, I've adjusted that little 'rule' there. As long as it can fit on a 7800 PCB, it's just fine.

Ok, that raises another question about the specs of available PCB(s).
What are the recommended/available ROM sizes (and eventually supported BS schemes)?

Greetings,
Manuel

The smallest 7800 PCB was 16K, the largest 144K (also a 512K one that was made but never used). For bankswitching info see Eckhard's 7800 bankswitching guide.

Mitch

[Cybergoth]

Hi there!

Mitch said:

Cybergoth said:

Ok, that raises another question about the specs of available PCB(s).
What are the recommended/available ROM sizes (and eventually supported BS schemes)?

The smallest 7800 PCB was 16K, the largest 144K (also a 512K one that was made but never used). For bankswitching info see Eckhard's 7800 bankswitching guide.

I was more asking what is recommended to use now for the contest, rather than what things had been done in the past. I'd guess writing a game assuming a POKEY chip on the PCB would out of scope for example?

More or less I'm interested what cartridges can AA produce? Just unswitched 7808, 7816, 7832 and 7848 cartridges or switched cartridges with more ROM as well?
(Best would certainly be if SG with 8 16K ROM banks would be supported.)

Greetings,
Manuel

[Shaggy the Atarian]

Cybergoth said:

Hi there!

Mitch said:

Cybergoth said:

Ok, that raises another question about the specs of available PCB(s).
What are the recommended/available ROM sizes (and eventually supported BS schemes)?

The smallest 7800 PCB was 16K, the largest 144K (also a 512K one that was made but never used). For bankswitching info see Eckhard's 7800 bankswitching guide.

I was more asking what is recommended to use now for the contest, rather than what things had been done in the past. I'd guess writing a game assuming a POKEY chip on the PCB would out of scope for example?

More or less I'm interested what cartridges can AA produce? Just unswitched 7808, 7816, 7832 and 7848 cartridges or switched cartridges with more ROM as well?
(Best would certainly be if SG with 8 16K ROM banks would be supported.)

Greetings,
Manuel

While we can't give a direct answer (yet), we'd like to support POKEY and games larger than 144k. So if you do write something along those lines, it's not out of the question for the contest. When there is a definentive answer for this question, I'll be sure to let you know. :wink:

[Mitch]

If they can build 2600 bankswitched boards I don't see a problem with building 7800 bankswitched boards. They aren't that complex.

Mitch

[Bruce Tomlin]

Robert M said:

I don't understand the reasoning behind this rule in the contest:

"File Size must not be smaller than 8kb. Anything above that that the 7800 can handle is fine. "

I mean, is it an emulator issue, or a manufacturing issue?   Plus. are we penalized if our program is only 6K bytes and we pad the reamining 2K bytes with zeros?    

Cheers!

Actually, it's pretty hard to make a 7800 game smaller than 8K, because the extremely useful "holey DMA" mode of the Maria only works on 8K or 16K boundaries. You could get away with 4K if you didn't need sprites straddling two zones. Any less than that, and things get tricky. It might be possible with 4-line zones, but that would be more trouble than it was worth.

It would also be interesting for people to try writing code that uses the TIA chip either in expanded 2600 mode (using a 7800 cart) or full 7800 mode (with the 7800 memory mapping). This requires proper manipulation of $01 to switch video, but should allow 32K of total addressing space, in all the odd 4K blocks. This is equivalent to how a typical bank-switched cart is developed, only without the need for bank switching. You would need a digital signature to use the 7800 memory addressing mode, but expanded 2600 mode only requires a 7800 cartridge board.

What could YOU do with 2600 code that had 4K of fully usable SRAM?

[Bruce Tomlin]

Cybergoth said:

More or less I'm interested what cartridges can AA produce? Just unswitched 7808, 7816, 7832 and 7848 cartridges or switched cartridges with more ROM as well?  
(Best would certainly be if SG with 8 16K ROM banks would be supported.)

I wasn't aware that anybody had any kind of 7800 cartridge boards. Right now the only way is to open up a cartridge with the desired board, desolder the chip(s) from it, then add a 7404 (for non-supercart boards) and your own EPROM.

(And please, if they do decide to do some, ask me for suggestions!)

[Albert]

Bruce Tomlin said:

Cybergoth said:

More or less I'm interested what cartridges can AA produce? Just unswitched 7808, 7816, 7832 and 7848 cartridges or switched cartridges with more ROM as well?  
(Best would certainly be if SG with 8 16K ROM banks would be supported.)

I wasn't aware that anybody had any kind of 7800 cartridge boards. Right now the only way is to open up a cartridge with the desired board, desolder the chip(s) from it, then add a 7404 (for non-supercart boards) and your own EPROM.

(And please, if they do decide to do some, ask me for suggestions!)

We are currently investigating which type of 7800 board we should make. We want to support reasonably large games (the 512K board sure looks nice!) and an optional POKEY chip for homebrew authors who want to support that. Our intent is to make a board that will support games in any size up to the maximum, with or without the POKEY. Unfortunately, we do not have any 512K boards to examine, since no games ever came out to support them.

..Al

[ubersaurus]

Albert said:

Bruce Tomlin said:

Cybergoth said:

More or less I'm interested what cartridges can AA produce? Just unswitched 7808, 7816, 7832 and 7848 cartridges or switched cartridges with more ROM as well?  
(Best would certainly be if SG with 8 16K ROM banks would be supported.)

I wasn't aware that anybody had any kind of 7800 cartridge boards. Right now the only way is to open up a cartridge with the desired board, desolder the chip(s) from it, then add a 7404 (for non-supercart boards) and your own EPROM.

(And please, if they do decide to do some, ask me for suggestions!)

We are currently investigating which type of 7800 board we should make. We want to support reasonably large games (the 512K board sure looks nice!) and an optional POKEY chip for homebrew authors who want to support that. Our intent is to make a board that will support games in any size up to the maximum, with or without the POKEY. Unfortunately, we do not have any 512K boards to examine, since no games ever came out to support them.

..Al

Just make sure it supports onboard RAM

[Albert]

ubersaurus said:

Just make sure it supports onboard RAM  

How many 7800 games took advantage of carts with onboard RAM? Adding RAM to a board makes them more complicated and more expensive to produce. How much onboard RAM does the 7800 have?

..Al

[CPUWIZ]

Albert said:

How much onboard RAM does the 7800 have?

..Al

TheGodDamned F.A.Q. on AA said:

RAM: 4K, high speed (mostly VRAM)

[Mitch]

Albert said:

Bruce Tomlin said:

Cybergoth said:

More or less I'm interested what cartridges can AA produce? Just unswitched 7808, 7816, 7832 and 7848 cartridges or switched cartridges with more ROM as well?  
(Best would certainly be if SG with 8 16K ROM banks would be supported.)

I wasn't aware that anybody had any kind of 7800 cartridge boards. Right now the only way is to open up a cartridge with the desired board, desolder the chip(s) from it, then add a 7404 (for non-supercart boards) and your own EPROM.

(And please, if they do decide to do some, ask me for suggestions!)

We are currently investigating which type of 7800 board we should make. We want to support reasonably large games (the 512K board sure looks nice!) and an optional POKEY chip for homebrew authors who want to support that. Our intent is to make a board that will support games in any size up to the maximum, with or without the POKEY. Unfortunately, we do not have any 512K boards to examine, since no games ever came out to support them.

..Al

Actualy there is, Commando is on a 512 board with a Pokey chip though the game itself is only 128KB. You can check out the board schematics on Dan's site.
Hmm, it looks like the link to the PDF is broken on that page. I guess you can email Dan for it, actually I downloaded it as well so I can send it to anyone that wants it.

Mitch

[Feralstorm]

Don't know if it's welcome or not, but if any home-brewer is looking for someone to help with game graphics and the like. I'd (probably) be willing. I'd just need to learn the basics/limits of 7800 graphics/sprites first.

[Eckhard Stolberg]

Albert said:

How many 7800 games took advantage of carts with onboard RAM?  Adding RAM to a board makes them more complicated and more expensive to produce.  How much onboard RAM does the 7800 have?

There were five games released with RAM in the cartridge. The three games by Epyx (Impossible Mission, Summer Games and Winter Games) and the two games by US Gold (Jinks and Tower Toppler) had 8K or 16K in the same address space as the POKEY in Ballblazer and Commando. Also the Rescue on Fractalus prototype has a weird 2K RAM setup. The 7800 itself only had 4K of RAM build in.

Adding RAM to the cartridge is probably a little cheaper and simpler than adding the POKEY, because the chips are smaller and easier to find. Only if you wanted to have POKEY and RAM on a board, things might become a little complicated. You might need to add a jumper to select between both setups. But you probably might need jumpers anyway, if you wanted to support many different ROM setups with the same board. Atari's bankswitching boards were like this, so you might be able to learn from their design.

And if you wanted to support the POKEY and RAM in the same game, you could easily map the POKEY into a different free spot in the 7800's memory map. There are plenty of spaces where the 16 registers of the POKEY would fit in. Since no homebrew games with POKEY support were finished yet, it probably wouldn't be a problem if the registers were moved to different addresses than in Atari's own games.


Ciao, Eckhard Stolberg

[Eckhard Stolberg]

Bruce Tomlin said:

It would also be interesting for people to try writing code that uses the TIA chip either in expanded 2600 mode (using a 7800 cart) or full 7800 mode (with the 7800 memory mapping).  This requires proper manipulation of $01 to switch video, but should allow 32K of total addressing space, in all the odd 4K blocks.  This is equivalent to how a typical bank-switched cart is developed, only without the need for bank switching.  You would need a digital signature to use the 7800 memory addressing mode, but expanded 2600 mode only requires a 7800 cartridge board.

What could YOU do with 2600 code that had 4K of fully usable SRAM?

While it would be possible for a 2600 game on a 7800 board to use 32K of somewhat linear ROM or even a large amount of linear extra RAM on the cartridge, I don't think it would be that easy to use the 7800's system RAM from a TIA game. If you enable the 7800's system RAM, you'll also enable the MARIA registers. And those will overlap with some of the TIA graphics registers. Therefore you'd have to be really carefull with what you write to the TIA registers to not trigger some unwanted interference from the MARIA DMA. Also the RAM support enables the faster CPU speed, which slows down for every access to the TIA. Therefore cycle counting your TIA accesses in the display kernel would become quite difficult.


Ciao, Eckhard Stolberg

[Cybergoth]

Hi there!

Eckhard Stolberg said:

Ciao, Eckhard Stolberg

So do your answers in this thread indicate your triumphant return as game programmer?

Greetings,
Manuel

[Shaggy the Atarian]

Feralstorm said:

Don't know if it's welcome or not, but if any home-brewer is looking for someone to help with game graphics and the like. I'd (probably) be willing. I'd just need to learn the basics/limits of 7800 graphics/sprites first.

Hello!

Curt posted a 7800 animation program for use on Atari STs in this thread that you may be interested in and can use. I've played around with it a little bit but I haven't had the time to really figure it out. Hopefully it could be of some use to you.

[Feralstorm]

That would likely be useful, assuming I can find a way (as an Amiga and Pegasos 2 user) to make use of it. I'll have to see what I can track down in emulators, and/or friends with ST's.

[Eckhard Stolberg]

Cybergoth said:

So do your answers in this thread indicate your triumphant return as game programmer?

Probably not. And if I did, I guess my return wouldn't be that triumphant anyway, because it seems that I would have to be competing with you.


Ciao, Eckhard Stolberg

[Cybergoth]

Hi there!

Eckhard Stolberg said:

Cybergoth said:

So do your answers in this thread indicate your triumphant return as game programmer?

Probably not. And if I did, I guess my return wouldn't be that triumphant anyway, because it seems that I would have to be competing with you.

Greetings,
Manuel