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AtariProtos.Com Update


Tempest

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I've made a few updates to my website. The biggest news is a new and almost complete version of Xevious, but there's also Morse Code Tutor and Elf Adventure.

 

Check it out: http://www.atariprotos.com/

 

I will release the rom for Morse Code Tutor soon, but Xevious will have to wait until I get permission. I'm working on that.

 

 

EDIT: I've attached the roms for Morse Code Tutor, Elf Adventure, and FM Synth Cart

protos.zip

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More contributions, Tempest. Excellent!

 

On your Protos page for Rubik's Cube, you say:

 

"While the game appears to be the same as the final release, this prototype is 8K. The final release was only 4K, so one has to wonder what they needed the extra space for?"

 

At PRGE 2013, Joe DeCuir said that while developing games for the 2600 AFTER Intellivision hit the market, to save money Atari bought defective 8k chips instead of good 4k chips because they were SIGNIFICANTLY cheaper, then utilized the functional 4k portions of the defective chips where possible. This may be the answer to your Rubik's Cube prototype question.

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Nice updates, Tempest! But as I let you know in a PM, I've been having a problem with some pages of your website not displaying properly. Here are some screenshots:

 

post-7728-0-76339300-1411075380_thumb.png

post-7728-0-67472500-1411075397_thumb.png

post-7728-0-01936700-1411075412_thumb.png

 

As you can see, all of those pages are expanding off the sides of the screen. All of the other pages that I have checked on your site display properly so it seems to be some kind of new formatting problem. Has anyone else noticed this?

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Matt, did you update the screen shots for Xevious as well? Seem different than I remember. More enemies and artwork. Wondering if the BEST Electronics prototype boards that were sold in the late 90's (were those the '83 version?) were a lower revision than that of the 1984 one you just posted?

 

Be nice to hear about how you stumbled on the latest "almost complete" version…

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Matt, did you update the screen shots for Xevious as well? Seem different than I remember. More enemies and artwork. Wondering if the BEST prototype boards that were sold in the late 90's (were those the '83 version?) were a lower revision than that of the 1984 one you just posted?

 

Be nice to hear about how you stumbled on the latest "almost complete" version…

Yes the main page now reflects the newer version of Xevious which is more or less complete. I'm guessing the Best proto is the 8-2-83 version as that is the most common proto of Xevious.

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More contributions, Tempest. Excellent!

 

On your Protos page for Rubik's Cube, you say:

 

"While the game appears to be the same as the final release, this prototype is 8K. The final release was only 4K, so one has to wonder what they needed the extra space for?"

 

At PRGE 2013, Joe DeCuir said that while developing games for the 2600 AFTER Intellivision hit the market, to save money Atari bought defective 8k chips instead of good 4k chips because they were SIGNIFICANTLY cheaper, then utilized the functional 4k portions of the defective chips where possible. This may be the answer to your Rubik's Cube prototype question.

 

Wow, that's more of a Commodore-type move than an Atari Inc. move...

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Stupid question perhaps, and feel free to point me somewhere to search, but is that newer Xevious binary available anywhere to download?

No, it's not available at this time. I'll let everyone know when/if it becomes available. Sorry about that.

 

 

 

In the meantime, enjoy these roms instead:

 

Morse Code Tutor - There may be more functionality in this rom than I can find. As I mentioned in my review, it's kind of hard to use.

 

FM Sound Tool - I haven't reviewed this one yet, but I'll post the rom anyway. This is an FM Sound generation tool that someone at Atari was working on in the early 80's. It uses the keypad controllers and generates no video (you just see some random garbage). The controls are as follows:

 

 

 

  • SELECT cycles through 4 sound generation algorithms called EXP (default), DUO, FM and RM
  • RESET changes some presets of the current algorithm

So in total you have 8 sound presets to chose from.

Within Stella (I have no keypads), on the keyboard, the outer 2 rows on the left and right keypad (1QAZ 2WSX and 8IK, 9OL.) play notes. The lowest pitch is on 8, the highest on X, so the keypads are swapped.

The D key (there should be another key on the right keypad which manipulates in reverse, but that seems not to work, at least not in Stella; if you have keypads, please try on hardware) manipulates the current sound:

  • if RD (right diff) = A and B/W, the attack time is decreased
  • if RD = A and COLOR, the decay time is decreased

    (for the meaning of attack, decay, which are part of the so called envelope, read here.)

  • if RD = B and LD = A the frequency is decreased
  • else (which is the default when you start Stella) a parameter called Depth is decreased, this only has effect on the sound presets EXP and FM. Cool effect, especially with FM!

 

The rom I've posted fixes some bugs. Enjoy!

protos.zip

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It's mind-blowing that the VCS is capable of FM synthesis! I'd imagine it's far too CPU-intensive for use in a game, but I can still think of a lot of things that could be done with it.

 

BTW is there any reason that the rightmost keypad column isn't active? At the moment only half of the notes in each octave are available as far as I can tell, but if the right column were active we could have 9/12 notes per octave.

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It's mind-blowing that the VCS is capable of FM synthesis! I'd imagine it's far too CPU-intensive for use in a game, but I can still think of a lot of things that could be done with it.

 

BTW is there any reason that the rightmost keypad column isn't active? At the moment only half of the notes in each octave are available as far as I can tell, but if the right column were active we could have 9/12 notes per octave.

No idea. I do know that the keypad code in the original proto was a bit broken so Thomas fixed it. Maybe he missed something or the proto never had any functionality for that?

 

Personally I wish that there was some display like the Atari Video Music so you can see some pulsating graphics along with your 'music'.

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On both keypads two columns are used for playing notes. From the 3rd column only one key each is used (and one was even broken).

 

The code looks like the developer tried to get it to work "somehow" and then just had started playing with some parameters. Probably he would have added more features if he hadn't abandoned it. Or maybe some later version exists somewhere.

Edited by Thomas Jentzsch
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What would it take to add that third column? I haven't looked at the code -- do we have source? -- but I assume that either a constant based on the twelfth root of two is being used to calculate the frequency relationships between the buttons on the fly, or they're using hardcoded lookup tables.

 

In any event, the output frequency ratio between buttons 1 and 2, 4 and 5, etc. should be ~1.0595, whereas the difference between 2 and 4 is (1.0595)^3. Hence that gapped, almost Arabic quality to the available notes. 1 on keypad 2 is also 1.0595x higher than 8 on keypad 1, so that's the one place a full chromatic scale is available.

 

Also, how is the FM effect being done to begin with? I know that you can potentially get any 5-bit waveform by setting AUDC0 to 0 and varying AUDV0, but how does that get turned into FM?

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It would probably be possible to utilize more keys for more notes. But probably a rewrite (based on the info from the current code) would be easier. The notes are hard coded, with an 8 bit resolution.

 

I haven't figured how exactly the sound is generated. There are quite a lot of parameters and sinus tables involved.

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What would it take to add that third column? I haven't looked at the code -- do we have source?

Yes we do, but I'd have to ask if that can be released. I was given permission to release the rom, but I never asked about the source (I assume it's ok, but better safe than sorry). It will be a few weeks before I can as the person I got it form is 'off the grid' for a bit.

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Dan Kramer found some 7800 EPROMs the other day and posted pics to our 7800 Facebook group.

 

He found "3600 Asteroids Part Rev 8 Checksum 37C4", the "AtariLab Temperature 6/1/84", one labeled just as "7800 A000/E000 5/11/84" and some PCBs labeled "32k EPROM Cartridge Prototype Rev 1".

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Wow neat! Is he going to dump these? Those sound really interesting.

 

Got a link to the group?

I'm on my phone right now so I can't copy/paste it but the group is named "Atari 7800 ProSystem Gamers". The tags are "Atari 7800" and "retro" so it should come up easily on a group search.

 

I checked your page for Asteroids but I couldn't tell if it was the same version. I thought this was the only known ROM of the 7800 version of the AtariLab cartridge but Curt has a pic of another one that was displayed at the 20th Anniversary 7800 party with the ex-GCC staff back in 2004. That version basically said it required the 7800

Keyboard.

 

Although Dan has lot of stuff and tools, I don't think he has a means of dumping (EP)ROMs.

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