What makes a Supercharger game... a Supercharger game?

[RetroFiends]

As far as I'm aware, it's not like we can just load up any old atari ROM onto a cassette then load that from the Supercharger.

What exactly does the super charger do? How is the data of the supercharger ROM converted to data readable by the unit? I did a google search for Starpath Supercharger homebrew, and came up with nothing other than claims that it existed.

 

In short, how does this thing work? Are there documents available or is this thing magic?

[+Gemintronic]

More RAM so you can make higher resolution games.

 

My thoughts are to make a standard 4k game and convert it to cassette using one of the utilities out in the wild. At least to get some new SuperCharger games out there. Cassettes can be had for nothing and even MP3 players are less than $6 dollars.

[linville]

"More RAM" is _why_, but I think that he is asking _how_...? I'd like to know too -- anyone have that info?

[RetroFiends]

Yep, how is the what I'm looking for. I mean, if we could somehow assemble games for use on a starcharger, this would give people another option when testing homebrew software, or even distributing said games. I know it's totally unnecessary since the Harmony Cart, but I love cassettes. The biggest benefit of course being super cheap to distribute. I mean, I can go to goodwill right now and I'll probably find at least one packgage of brand new cassettes for pocket change. And there is a multitude of media duplication services out there that also deal with cassettes for a more professional approach.

 

Unfortunately, I'm having a very difficult time finding anything on the details of how the thing actually works. Right now it's occult.

[+SpiceWare]

There's a program called MAKEWAV that converts the ROM file into a WAV file. The WAV can be burned to CD, saved to Tape, or even put on a device like an iPod. It will convert Supercharger specific games, as well as 4K games.

 

While a lot of 4K games will work just fine, some of them trigger the Supercharger's bankswitching and crash. A number of games have been patched to fix this problem. You can also modify the Supercharger to add a switch to disable the bankswitching, which lets those games play without needing to be patched.

[RetroFiends]

Excellent! So what it sounds like is that the ROMs themselves aren't actually anything special outside of conforming to what does and doesn't work with a Supercharger. Is there anything in particular that causes those 4k ROMs to not work? What triggers the bankswitching to occur in 4k games?

 

Edit:

That thread actually answered this question.

Any 2k/4k rom. You just need to avoid any program access from rom adresses $xFF8 on up. 2k by nature is no problem, since they only use 2k of the addressing space. 4k programs would need hacking if they do this.

 

So this is great news. 2k games are effectively ensured compatible, while 4k roms have additional considerations. With this in mind I might be making a Starpath game soon. I've been wanting to create a 2k game after the ridiculousness of this 32k game I've been working on.

Edited August 14, 2013 by RetroFiends

[raindog]

At least to get some new SuperCharger games out there. Cassettes can be had for nothing and even MP3 players are less than $6 dollars.

 

Unfortunately, as I learned when using my Cuttle Cart with several different mp3 players to get every Atari game and demo on one disc or SD card, even the highest quality MP3 compression settings still distort the audio enough to cause the load to fail most of the time.

 

If the $6 mp3 players will play lossless audio, though, that's a fun way to distribute games... at least to Supercharger and CC owners. Even sending a whole MP3 player out is probably cheaper than getting a cartridge made. But most of your users will need a cartridge or ROM image.

[+SpiceWare]

even the highest quality MP3 compression settings still distort the audio enough to cause the load to fail most of the time.

 

I used 128 bit AAC files on my iPod and it worked just fine. I remember having to use a higher bitrate to make an MP3 file work, but don't recall what I used.

 

I bet you were really having an issue with the volume setting. The Supercharger's are like Goldilocks - to too soft or too loud won't work, it has to be just right.

[raindog]

I would agree, except that the SGANB CD worked fine on the same MP3 CD player on which the MP3s failed, as did burning an audio CD of my own ROMs converted using makewav. (Also, I was using the CC, not the Supercharger.)

 

But it doesn't surprise me that AAC would fare significantly better.

[alex_79]

In theory even 2k games can crash: in a 2k cartridge there's an address pin missing (the A11 line), so the rom is mirrored twice in the 4k address space and if the program refers to addresses in the upper mirror ($x800-$xFFF), then there's the possibility to trigger the sc bankswitch. Address $x7F8 and $xFF8 both points to the same phisical address of the rom chip, but using the second one will crash the game on a supercharger.

 

I bet you were really having an issue with the volume setting. The Supercharger's are like Goldilocks - to too soft or too loud won't work, it has to be just right.

I agree. Before I bought my Harmony cart I used the supercharger a lot. I used 320 kb/s mp3 files on a cheap player and I don't remember ever having problems with that.

[+SvOlli]

What's interesting to me is the question: how was/is this done on the software side? A quick search didn't show up any example code. Would it be possible to write self-modifing code, for example?

[enthusi]

Writing into supercharger memory is a bit of a pain.

You can check the supercharger docs/BIOS for it.

There are also example snippets (aside from lots of splendid technical information) here:

http://blog.kevtris.org/blogfiles/Atari%202600%20Mappers.txt

Which is linked to here:

http://2600scene.net

[Thomas Jentzsch]

The biggest benefit of course being super cheap to distribute.

IMO that the biggest downfall. There are two (non-disjunct) groups of people:

1. The gamers, who just want to play the game. They just need a ROM and their Harmony cart.
    
   
2. The collectors, who want a great packaging, a real cart, extras etc.
   

A cheap cassette distribution would be somewhere in the middle and make no one really happy. There have been several attempts (e.g. by Glenn Saunders) for more than 10 years to motivate programmers to use the SC. And AFAIK all have failed.

[Mr SQL]

IMO that the biggest downfall. There are two (non-disjunct) groups of people:

1. The gamers, who just want to play the game. They just need a ROM and their Harmony cart.
    
   
2. The collectors, who want a great packaging, a real cart, extras etc.
   

A cheap cassette distribution would be somewhere in the middle and make no one really happy. There have been several attempts (e.g. by Glenn Saunders) for more than 10 years to motivate programmers to use the SC. And AFAIK all have failed.

 

I think if the packaging and look of the Starpath cassette games were replicated as is done with the cartridges they could be interesting to both collectors and gamers!

 

6K of RAM looks pretty developer friendly compared to the superchip, I think I'd like to give it a try; have you coded anything to the SC?

[enthusi]

It's not like you have 6K of RAM instead of 128 Byte.

Also I have to agree with Thomas, though for the C64-scene tapes work still pretty well, I doubt it would for the Supercharger.

Mostly due to the fact that hardly anyone owns AND uses a supercharger. Of those that do, probably only a small fraction actually loads from a tape-player rather than straight from CD or PC.

And distributing Audio-files as WAV or even MP3 would be just the same as binaries straight away.

That being said, I have plans for a game-project that might become larger than 4K

[Mr SQL]

It's not like you have 6K of RAM instead of 128 Byte.

Also I have to agree with Thomas, though for the C64-scene tapes work still pretty well, I doubt it would for the Supercharger.

Mostly due to the fact that hardly anyone owns AND uses a supercharger. Of those that do, probably only a small fraction actually loads from a tape-player rather than straight from CD or PC.

And distributing Audio-files as WAV or even MP3 would be just the same as binaries straight away.

That being said, I have plans for a game-project that might become larger than 4K

enthusi,

I didn't mean to imply the 6K of RAM was all available with this format, I haven't worked with it but I imagine one configuration possible would be two banks, each with 2K of "ROM" and 1K of RAM with seperate read/write addresses for a total of a 4K ROM game with 2K of RAM (obviously stored in 6K of RAM space).

That's a big step up from the extra 128 or 256 bytes you get with the superchip or CBS RAM; more graphics.

 

The game project sounds cool! Is it going to be for the supercharger?

Edited August 19, 2013 by Mr SQL

[alex_79]

[...] I haven't worked with it but I imagine one configuration possible would be two banks, each with 2K of "ROM" and 1K of RAM with seperate read/write addresses for a total of a 4K ROM game with 2K of RAM (obviously stored in 6K of RAM space).

 

There aren't separate addresses for read and write operations in the supercharger, so the entire cartridge address space can be configured as ram. Anyway, writing to ram is slow and a bit intricate.

Writing to SC ram is performed using just read operations (write instructions would cause bus contention): you first access an address in the first page of the 2600 cart space ($F000-$F0FF). This will start the SC write operation and the least significant byte of the address is the value that will be written. The supercharger will then write that value to the fift address which is accessed (if it's in cart space and in a bank configured as ram).

 

This is well explained in kevin Horton's document linked before and also in the Programmer's Section of the Cuttle Cart manual (There are scan's of it on AtariAge main site)

[RetroFiends]

IMO that the biggest downfall. There are two (non-disjunct) groups of people:

1. The gamers, who just want to play the game. They just need a ROM and their Harmony cart.
    
   
2. The collectors, who want a great packaging, a real cart, extras etc.
   

A cheap cassette distribution would be somewhere in the middle and make no one really happy. There have been several attempts (e.g. by Glenn Saunders) for more than 10 years to motivate programmers to use the SC. And AFAIK all have failed.

 

While I won't argue that a supercharger release wouldn't be an incredibly niche venture, that's not to say it isn't worth the venture. After all, everything we do here is incredibly niche in the first place. If I could release a supercharger game to even 5 people who end up happy with it, I would consider it a job well done. It's a matter of perspective, I suppose.

 

That said, and as has already been said in #14 in this thread, it's more than possible to make a beautiful cassette release. The amount of options to make your cassette stand out are listless and as I said before there are plenty of tape duplication services and even cassette manufacturers that will bend over backwards to produce what you need. You can get cassettes done in nearly any color, printed on in any number of ways, and of course the case inserts are just as doable as any other media format. (Albeit, inserts would have to be smaller unless you wanted a full box as Starpath games did.)

 

Additionally, there's no reason why we'd have to limit a game to supercharger release, it would simply be one more option available.

[+save2600]

Joe's DK VCS is coming along excellently, but imagine a well written Starpath DK Arcade experience! Level data so large that you could load each as you go, static non-scrolling levels, slanted girders, prizes, multicolored sprites, proper A.I., etc.

 

Burn the finished program to CD and include Buckner and Garcia's 'Do The Donkey Kong' on it to listen as you play the game.

[raindog]

Joe's DK VCS is coming along excellently, but imagine a well written Starpath DK Arcade experience! Level data so large that you could load each as you go, static non-scrolling levels, slanted girders, prizes, multicolored sprites, proper A.I., etc.

Er, that's assuming that a single level of Joe's masterpiece could fit into the Supercharger's 6K. I don't think that's a given at all. Also, that limits you to a single level order, you have load times between levels and every time you start a game after having beaten the first level, and eventually you'll even have to rewind the tape mid-game.

 

I still hope to see an epic Harmony-specific game someday that loads megs and megs of assets and level maps from the MicroSD card, the conclusion of the logical progression that started with the Supercharger and Pitfall 2. Given the size of the audience (smaller than that of the Supercharger) and the effort that would require, it seems unlikely to be more than a thought experiment. But it'd be fun to have, say, a demake of Knytt Underground, the enormous non-scrolling adventure platformer which itself is kind of like the conclusion of the logical progression that began with Pitfall.

Edited August 19, 2013 by raindog

[iesposta]

 

I still hope to see an epic Harmony-specific game someday that loads megs and megs of assets and level maps from the MicroSD card, the conclusion of the logical progression that started with the Supercharger and Pitfall 2. Given the size of the audience (smaller than that of the Supercharger) and the effort that would require, it seems unlikely to be more than a thought experiment. But it'd be fun to have, say, a demake of Knytt Underground, the enormous non-scrolling adventure platformer which itself is kind of like the conclusion of the logical progression that began with Pitfall.

I hope too. Especially when you read, "Melody board can be made with 128K of Flash memory and 64K of RAM; And if that's not enough, the Melody can be fitted with an optional EEPROM chip up to 4MB."

[RetroFiends]

I still hope to see an epic Harmony-specific game someday that loads megs and megs of assets and level maps from the MicroSD card, the conclusion of the logical progression that started with the Supercharger and Pitfall 2. Given the size of the audience (smaller than that of the Supercharger) and the effort that would require, it seems unlikely to be more than a thought experiment. But it'd be fun to have, say, a demake of Knytt Underground, the enormous non-scrolling adventure platformer which itself is kind of like the conclusion of the logical progression that began with Pitfall.

 

Well, the game I'm working on isn't nearly to the scale of that but it is relatively massive on a per screen account. This game is 32k and is looking like there will be little room to spare. Batari Basic is helping to make this whole process doable for someone new to the system, but of course there are limitations. Since playfield graphics are forced to the last bank and the game is already 29 screens with more on the way, I've made thorough use of playfield variables.

 

Needless to say, that ain't gonna fit on a cassette

 

Back to the topic at hand, I think people are being a little optimistic about what you can actually squeeze out of the SuperCharger. 6k of ram isn't a lot of ram at all once you understand that you're loading your entire rom into that ram. High resolution games will undoubtedly take a large portion of said ram, and then you have to fit all the game logic into it. The reality is that anything you would make would essentially be a beefy 4k game in quality.

[iesposta]

6K of RAM is RAM, not ROM.

RAM can be modified.

Look at Supercharger Suicide Mission, or the better prototype, Meteroids

That screen is done by changing the display in RAM.

Other "tricks" can be done when everything is RAM.

And Multi-Loading could have made some great expansive games.

You could do a Donkey Kong from tape or CD, one screen per load.

You have the whole tape/CD to work with!

Level 1,2,3,4, harder Level 1,2,3,4, even harder Level 1,2,3,4, hardest Level 1,2,3,4 and there would still be room left.

Back in the 80s I wouldn't have minded waiting for the next part to load, but today we have larger bank switch formats so Multi-loading isn't attempted.

[RetroFiends]

6K of RAM is RAM, not ROM.

I'm aware of that. But from my understanding the supercharger dumps the entire "ROM" (in this case, the audio file) into the Supercharger's RAM, meaning that at any point the only RAM you have is 6k - "Rom" size. Granted, yes with multi loading and some cleverness you could theoretically make some some massive games but after a point you're pretty much forced to mp3/CD use. Not because there isn't enough room on tape --there is, but because you're ultimately always working with 6k - ROM chunks and the only end-user - friendly arrangement would require flipping the tape - Something you can only do so many times. Without a tape counter and the immediate attention of the player (stopping the tape right when you're given the que) you can only get so sophisticated.

 

So, here you have end user limitations, plus 6k RAM - ROM. Higher resolution graphics cut out what you can do with game logic tremendously with your game logic in any given 6k chunk, and then of course also needs to be room for multi-load handlers. Sure, theoretically you could make some pretty massive games, but when you're switching audio files every 10 screens it's not at all practical. Nonetheless, I wouldn't mind seeing someone go absolutely mad at the expense of the end user just to see how far a Starpath game can go.

[raindog]

If someone can show me a proof of concept in the form of a title screen plus the first level of a Donkey Kong that's as good as what Joe did, but fitting into a single Supercharger load, I will believe the "one load per level" idea is at least possible. Even if it is, though, I still think a Harmony/Melody solution would be able to reach more players and be a better experience for them, even if they consider using modern data storage or DPC+ to be "cheating".

 

6K of RAM is RAM, not ROM.

RAM can be modified.

 

As others have noted, Supercharger RAM is slower to write to than other forms of expanded RAM, and even then, you still have only 6K for all of your game code plus at least one level of game data, a title screen if you want one, and whatever you want to do with the RAM. Meteroids/Suicide Mission is pretty much the only production example of the Supercharger RAM being put to good use, and that is a far, far simpler game than Donkey Kong.

 

I look forward to seeing what you come up with.