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Atari 5200 prototype - Paul Comfort's Demo


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#1 Video 61

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Posted 02 September 2017 - 05:26 PM

This demo for the Atari 5200, we think, was to be used to test joystick movements for the Atari 5200 controllers, as the joystick fire buttons serve no purpose in the function of the demo.

 

 

 

 

 

 

thanks for viewing,

 

lance

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#2 kamakazi20012

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Posted 02 September 2017 - 10:54 PM

Interesting demo.  However, Lance, the ROMs are reversed from the 8-bit line of carts.  On the 5200 the right side of that cart board is for Lo memory locations  starting at $4000 and the right side is for high memory locations starting at $8000.  That chip is actually in the lo position not the high position.  Just thought I would let you know.


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#3 Video 61

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Posted 03 September 2017 - 12:32 AM

Interesting demo.  However, Lance, the ROMs are reversed from the 8-bit line of carts.  On the 5200 the right side of that cart board is for Lo memory locations  starting at $4000 and the right side is for high memory locations starting at $8000.  That chip is actually in the lo position not the high position.  Just thought I would let you know.

 man, i thought i had it right. i need to try that again with venture. but on other protos i have, there are e-proms saying low on the left side. i will give venture a whirl and let you know.

 

lance

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#4 Ballblaɀer

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Posted 03 September 2017 - 11:42 AM

Interesting that this carries a 1984 copyright date; the demo currently in circulation ("Yellow Sub Demo", which appears to be identical to this one) has a 1983 date on the Fuji screen.

 

Some internal mail from Atari's Vax servers in the Home Computer Division indicate that Paul Comfort was in "Component Test Engineering", and around this time (early February 1984) HCD was looking at an issue in the SALLY chip in A8 computers -- something to do with the data bus and the CLC (Clear Carry Flag) opcode failing in a high percentage of chips when operated at high temperatures.  I know very little about 6502 programming but I gather that the CLC opcode *does* get used in some sprite positioning routines.  I'm gonna guess that this demo wasn't related to that specific issue (I'm not even sure if the 5200 used the same SALLY revision that was being tested at the time), but it seems like the kind of quick-n-dirty cart that a test group might put together to put an IC through specific paces.

 

Thanks for sharing this with the community!


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#5 Video 61

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Posted 03 September 2017 - 12:16 PM

Interesting that this carries a 1984 copyright date; the demo currently in circulation ("Yellow Sub Demo", which appears to be identical to this one) has a 1983 date on the Fuji screen.

 

Some internal mail from Atari's Vax servers in the Home Computer Division indicate that Paul Comfort was in "Component Test Engineering", and around this time (early February 1984) HCD was looking at an issue in the SALLY chip in A8 computers -- something to do with the data bus and the CLC (Clear Carry Flag) opcode failing in a high percentage of chips when operated at high temperatures.  I know very little about 6502 programming but I gather that the CLC opcode *does* get used in some sprite positioning routines.  I'm gonna guess that this demo wasn't related to that specific issue (I'm not even sure if the 5200 used the same SALLY revision that was being tested at the time), but it seems like the kind of quick-n-dirty cart that a test group might put together to put an IC through specific paces.

 

Thanks for sharing this with the community!

 ah, that could explain why the sprite just moves around, no need to test other functions of the stick. although, its a great test for joystick movement. and you are welcome.

 

lance

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#6 Clint Thompson

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Posted 04 September 2017 - 03:07 AM

Very cool! So it's actually a sub and not a shark? I couldn't help but feel this could've been a great JAWS game but I have an imagination I suppose... 


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#7 Video 61

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Posted 04 September 2017 - 06:59 PM

Very cool! So it's actually a sub and not a shark? I couldn't help but feel this could've been a great JAWS game but I have an imagination I suppose... 

 and that is what 8/16 bit gaming is all about, the usage of your imagination. i love it.

 

lance

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