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Atari 2600 Homebrews


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The great thing about the VCS (this may sound like a diss but it’s not I swear) is that it’s so low tech! The chipset is very well documented and understood and there’s not much to get in the way of exploiting every inch of it. If you write code that works on a Sunnyvale sixer it should work on 99.9% of 2600 variants out there, even clone systems and backward compatible devices. Just a half decade later things were already stupidly complicated. You’d think a Famicom game would work on any other Famicom but the more times they redesigned it to manufacture it more cheaply the more incompatibilities cropped up. Clone systems have exacerbated it. How many people can’t play a NES home brew because it only works right on 80’s chipsets? It’s not everyone but it does happen. Sometimes you can’t even play regular retail games like Castlevania 3. The VCS is great because it’s virtually the same every time. 

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The most important thing to run on real hardware is to strictly abide by the NTSC and PAL frame specifications. Emulators are tolerant of that, so you may not see a problem there. On CRTs the picture can roll, on modern TVs you might not get a picture at all. The second box of "Scn Ln" in Stella debugger will go brownish-red if you deviate from the standards.

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1 hour ago, Atari_Master said:

Are there any special requirements to make 2600 homebrew games work on an original 2600?  Also, is there a list showing which 2600 homebrew games don't work on the 2600? 

Are you asking because you want to program one? Or because you want to buy some and want to be sure they're going to work?

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I've not heard of a homebrew ROM that doesn't work if given the proper physical cart and board.

 

Some games might better on either a real TV or LCD panel.  For instance: Some games flicker the left 8 pixels of a sprite then the right 8 pixels of that sprite.  So, you see only half the sprite at any one time.  Depending on using a CRT TV or LCD monitor it may look hard to see.

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1 hour ago, Nathan Strum said:

Are you asking because you want to program one? Or because you want to buy some and want to be sure they're going to work?

I just wanted to buy a homebrew game and see if it would work on the original console.  I would assume that you insert the game and that's it.  I'm not sure about the compatibility though on which games will work.

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1 hour ago, Atari_Master said:

I just wanted to buy a homebrew game and see if it would work on the original console.  I would assume that you insert the game and that's it.  I'm not sure about the compatibility though on which games will work.

All homebrews in cartridge format will work just fine on an original console.

Yes, you just "plug 'n play" :)

The only "incompatibility" is you need a cartridge for your country's TV format - NTSC in the USA. PAL in Europe/Oz.

So, just make sure you are buying a PAL or NTSC version depending on what your TV displays.

Many modern homebrews are switchable and compatible with both.

 

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1 hour ago, Atari_Master said:

I just wanted to buy a homebrew game and see if it would work on the original console.  I would assume that you insert the game and that's it.  I'm not sure about the compatibility though on which games will work.

Any 2600 homebrew sold in the AtariAge Store should work on any original 2600 console that's in working condition. The games are tested thoroughly on a variety of 2600's to make sure they'll work on as many variants as possible. On the rare occasion an issue does crop up, it's fixed pretty quickly and anyone with an affected game can get their copy replaced.

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10 hours ago, Andrew Davie said:

All homebrews in cartridge format will work just fine on an original console.

Yes, you just "plug 'n play" :)

The only "incompatibility" is you need a cartridge for your country's TV format - NTSC in the USA. PAL in Europe/Oz.

So, just make sure you are buying a PAL or NTSC version depending on what your TV displays.

Many modern homebrews are switchable and compatible with both.

 

Okay.  Good to know.  Thank you!

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10 hours ago, Nathan Strum said:

Any 2600 homebrew sold in the AtariAge Store should work on any original 2600 console that's in working condition. The games are tested thoroughly on a variety of 2600's to make sure they'll work on as many variants as possible. On the rare occasion an issue does crop up, it's fixed pretty quickly and anyone with an affected game can get their copy replaced.

Yes, I figured they would work fine on original hardware.  I just wanted to make sure ahead of time.  Thanks!

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15 hours ago, p1FqO3 said:

The second box of "Scn Ln" in Stella debugger will go brownish-red if you deviate from the standards.

 

The fields on the debugger screen change to that color if they changed since the last time you looked at the debugger screen.  If that box went red then the scanline count is not consistent over time, which will cause the screen to jitter and/or roll.

 

Scanlines should be 262 for NTSC or 312 for PAL.  Air Raid is 290 scanlines when the game is not being played, so not correct for either NTSC or PAL, but it's not displayed in red*.

 

377451148_ScreenShot2019-12-12at8_58_32AM.thumb.png.815186bfcf05ffb806d7ddc8eaa160e4.png

 

Start a game and it changes to 291 scan lines, so turns red

 

1351631639_ScreenShot2019-12-12at8_58_41AM.thumb.png.a2132a9b0391a751fce339efba7f735f.png

 

It mostly stays at 291, so the red goes away

 

948726853_ScreenShot2019-12-12at8_58_46AM.thumb.png.9f6aef9039fc8f3578570c8c2c799a61.png

 

but occasionally jumps to 292, which causes the red to return

 

1115253855_ScreenShot2019-12-12at9_02_59AM.thumb.png.0bf7b5eb02b053033b0e0eb756c5cc18.png

 

* except for the first time you enter the debugger as everything's considered changed so everything's red

1802755539_ScreenShot2019-12-12at9_04_45AM.thumb.png.4840bd1aa42745b5396739ac3b2bf9a1.png

 

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  • 3 weeks later...
On 12/11/2019 at 3:59 PM, Atari_Master said:

Are there any special requirements to make 2600 homebrew games work on an original 2600?  Also, is there a list showing which 2600 homebrew games don't work on the 2600? 

All games work on original hardware. You can use my "List" to find any title.

https://tiny.cc/Atari2600Homebrew

 

 

 

 

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Hello everybody. I am 32 and just got my first Atari 2600 for Christmas. I had bought 12 Atariage homebrews back in September during the sale. I am now playing them and 2 of them don't work correctly. I was wondering if anybody knows any issues with these games or any other reason they may not work.

 

Scramble - The game plays and scrolls right but you cannot see your ship or any enemies on the ground. It is just the terrain scrolling right and my invisible ship crashes and game over.

 

Wall Jump Ninja - the game barely runs. The title screen comes up but skips and resets on its own. When I start the game, if it starts, the screen jolts and tears and very quickly resets back to title screen.

 

Old games from the 70s and 80s work fine on my 4 switch console and so do the other 10 homebrew games I have.

 

Any ideas what is wrong or what I should do?

 

Thank you

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Hi Chris,

 

I've sent you a PM so I can get replacement carts to you.  Obviously they should not behave as you described.  And the four-switch consoles tend to have the fewest issues running games in my experience (this includes some original games from Atari that are hit and miss on some of their consoles). 

 

 ..Al

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