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How rare are Atari 8-bit custom chips getting these days?

ANTIC GTIA POKEY SALLY & PIA

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#1 ACML OFFLINE  

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Posted Tue Aug 8, 2017 9:58 PM

There are four main custom chips in the Atari 8-bit family.  The ANTIC, GTIA, SALLY and POKEY.  The PIA was a common industry chip.  My question is, in 2017, how readily available are these to buy without having to buy a whole computer and canalizing it for parts?  I've notice that either B&C and/or Best is pulling the POKEYs off boards and selling them at a premium (~$20).  ANTICs in the 400/800/1200XL are 7 bitters and the 600/800XL/XE have 8 bitters.  GTIA appears to be unchanged.  As for the SALLY (6502C), those were found in the 400/800/XLs/XEs. The 400/800 CPU boards with SALLYs have a different PCB with less chips.  I see them on eBay, but are we getting close like so many other Atari parts to exhausting the supplies?  There are a lot of parts for the 400/800 and XLs that are no longer readily available and there typically is no warning.  Just an update from Best saying (SOLD OUT).       



#2 Kyle22 OFFLINE  

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Posted Tue Aug 8, 2017 10:59 PM

I don't know exact numbers on the actual custom chips, but I would like to add that C014806C (Sally) Isn't really that "custom". It has some logic integrated to halt the CPU to allow ANTIC to do bus master DMA.  This can be easily recreated with a PAL/GAL or a few simple TTL chips and a regular 65(x)xxx chip.  6502, 65C02, 65C802, and with small changes 65C816.

 

Sally is no problem.



#3 ACML OFFLINE  

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Posted Tue Aug 8, 2017 11:22 PM

Sally is no problem.

Yes, but if I just want to R&R a SALLY on a 1200XL, I can't do that with a 6502 or 6502B.  You have to have a 6502C in an XL or XE.  

 

To add to the discussion, what other smaller package chips on the 400/800 and 1200XL are custom to Atari.  I know the ROMs and MMU are, but are the rest generic industry parts?



#4 Keatah OFFLINE  

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Posted Wed Aug 9, 2017 3:43 AM

The question of when we're going to run out is moot. It will happen and that's all that need be known. More importantly, what replacements are available? And what replacements need to be produced? If direct replacements are never going to be made, what about small FPGA daughterboards that fit the 40 pin sockets for those custom chips?



#5 Level42 OFFLINE  

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Posted Wed Aug 9, 2017 4:24 AM

Don't forget that the last XE's (800XE I think) had faulty GTIA's which doesn't help the stock situation.

 

I'm actually still amazed by the number of POKEY's available. I think on one hand they don't die that easily (never saw a dead one, neither on my A8's or my arcade machines, and I used to own a Star Wars and several PCB sets for it, all containing 4 POKEYs).

The 7800 carts with POKEY's in them sure helped the supply situation too.

 

I simply have enough XL's with socketed stuff around to last me till my last breath. Also have a dead 130XE PCB only on which I'd like to remove every chip by "mass desoldering" and see if there are still working ones between them.

FPGA is the way to go, preferably single chips. 



#6 Keatah OFFLINE  

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Posted Wed Aug 9, 2017 4:44 AM

FPGAs will likely need to be on a daugherboard, which can be single-chip-sized, because they'll need some interface and support circuitry.

 

Some people like to say that you can get any custom chip made. So. Then. Get them made!



#7 flashjazzcat ONLINE  

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Posted Wed Aug 9, 2017 5:25 AM

I'm definitely short of POKEYs. :)

#8 DrVenkman OFFLINE  

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Posted Wed Aug 9, 2017 5:44 AM

POKEY chips can definitely die. I’ve had one go bad on a 1200XL. That said, Curt Vendel mentioned on Facebook recently that he has the films to have more made, assuming #1) Any company can still make custom chips with that technology from actual films; and 2) Someone had the high six figures to fund it.

#9 Level42 OFFLINE  

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Posted Wed Aug 9, 2017 5:52 AM

Yes of course they can die. Come to think of it I had once a XE that produced the self-test tune fine in channel 1 and 2 but went completely of key with the other two channels. It amazed me as I always thought that test was kind of a "lame" test :)

 

A year or two ago I bought some newly made DAC chips from China for a vector arcade game. Those DACs had risen in price insanely because they became so rare.

The company who originally developed them noticed this and smelled money.

 

They restarted production and asked a crazy price for them.

 

Of course, the Chinese smelled money too and started there "own" production. Cost was about 5% of the original. Bought the Chinese ones and they worked brilliantly.

 

For todays standards, those kind of chips are easy to make without production problems so even a "dodgy" Chinese factory can do it.



#10 Grover Torbel OFFLINE  

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Posted Wed Aug 9, 2017 6:35 AM

The timing of this topic blows me away. Just yesterday I ended up ordering two GTIAs and an ANTIC from Brad at Best. One GTIA is going into a malfunctionibg 5200, but the other two chips are spares. Maybe I should have picked up a POKEY and SALLY too.

#11 Grover Torbel OFFLINE  

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Posted Wed Aug 9, 2017 6:38 AM

1) Any company can still make custom chips with that technology from actual films; and 2) Someone had the high six figures to fund it.

Sounds like a good crowdfunding project. We could give away some sort of hat with a sufficient sized donation.

#12 Bryan OFFLINE  

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Posted Wed Aug 9, 2017 6:38 AM

I just watch for really beat up machines going cheap on ebay. It's much less expensive than ordering the chips.



#13 Tempest OFFLINE  

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Posted Wed Aug 9, 2017 7:21 AM

Lets hope that none of these chips ever get as expensive as working SID chips.  Those are getting rare enough that the Chinese are counterfeiting them!



#14 flashjazzcat ONLINE  

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Posted Wed Aug 9, 2017 7:22 AM

I just watch for really beat up machines going cheap on ebay. It's much less expensive than ordering the chips.


Yep. Paying 10GBP plus P&P per chip kind of goes against the grain. :)

#15 Bryan OFFLINE  

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Posted Wed Aug 9, 2017 7:46 AM

Yep. Paying 10GBP plus P&P per chip kind of goes against the grain. :)

BTW, I saw your endorsement of the UAV on YouTube. Thanks!

 

The future is going to be FPGA modules or whatever the future equivalent is. What would be cooler is home-printed IC's.



#16 Rybags OFFLINE  

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Posted Wed Aug 9, 2017 8:47 AM

The way I see it...

 

Pokey - I've got a dozen or more laying around courtesy of NTSC 7800 Ballblazer carts.  Probably a healthy surplus of Pokey's around but a stereo mod means 2 in one machine, arcade guys want them too and some people use them in distinct projects not involving control by an actual Atari piece of hardware.  Inner workings known well enough that a faithful modern day reproduction totally feasible.

 

PIA - probably not overly common but probably the second easiest to replicate using modern tech (after the MMU).

 

GTIA - modern day remakes and partial emulation in VBXE, probably overall less complex than Antic by a good deal so shouldn't be a problem in future.

 

6502C - as mentioned, if they became scarce a daughterboard adaptor project could be made to use an alternative.

 

MMU - already existing solutions to replace with GALs.

 

Delay Line - supposedly these guys are just off-the-shelf parts with Atari stampings and unused pins removed.  Probably not hard to replicate, and not needed in systems that use Freddie.

 

Freddie - a largely glue/logic type chip, wouldn't be hard to replicate the functions.

 

Antic - IMO probably the hardest custom chip to reproduce.  Probably not a lot of stocks around esp as they are in demand to convert machines to the other video system.  Luckily thanks to decap and research from various people the inner workings are probably known well enough to produce a faithful reproduction.



#17 Kyle22 OFFLINE  

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Posted Wed Aug 9, 2017 8:54 AM

The PIA is very common, and WDC still makes them.

 

http://www.westernde...65c21s-chip.cfm



#18 Bryan OFFLINE  

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Posted Wed Aug 9, 2017 9:02 AM

The delay line could be easily replaced by a small circuit board and even made tune-able for RAM upgrade stability.



#19 mytekcontrols OFFLINE  

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Posted Wed Aug 9, 2017 9:07 AM

I just watch for really beat up machines going cheap on ebay. It's much less expensive than ordering the chips.


With POKEY's going for $20 a piece, buying old machines as donors certainly became the 'better deal'. But I've noticed that it's getting harder to find motherboards or beat up machines as cheap as I did just a year or so back. And if that trend continues, which it likely will, then that cheaper alternative will soon disappear.

Pokey is and always has been the one in high demand, due to the popularity of stereo upgrades, and for people restoring arcade machines which use 4 at a pop in some cases.

We've heard about replacing this with an FPGA for years, as in the Hokey chip, but this is never fully realized. I think it is a $$$ making opportunity for an enterprising individual and a good use of a Kickstarter campaign to perhaps bring this into reality, either as an FPGA 40 pin carrier board, or better yet as a Chinese knock off of the real thing.

- Michael

#20 Bryan OFFLINE  

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Posted Wed Aug 9, 2017 9:24 AM

We've heard about replacing this with an FPGA for years, as in the Hokey chip, but this is never fully realized. I think it is a $$$ making opportunity for an enterprising individual and a good use of a Kickstarter campaign to perhaps bring this into reality, either as an FPGA 40 pin carrier board, or better yet as a Chinese knock off of the real thing.

The thing that scares me about Pokey alternatives is that we are still finding ways of using the chip that may not work unless 100% compatibility is maintained. I think there are still a lot of Pokeys out there since they were used by all divisions of Atari and were put into cartridges. It wouldn't surprise me if a warehouse of 7800 Ballblazers turned up some day. 



#21 ijor OFFLINE  

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Posted Wed Aug 9, 2017 9:34 AM

Pokey is IMHO the easiest of the chipset to reproduce accurately. Perhaps the most difficult part is the analog logic.

 

I am quite confident that we have all the information to reproduce the whole chipset with 100% cycle accuracy. It is certainly possible to reproduce individual chips with programmable logic. And if somebody needs some help from my decap research, just let me know.

 

But ... if you are going to replace the whole chipset with compatible reproductions in modern hardware, wouldn't be much better to go all the way and replace the whole board?

 



#22 mytekcontrols OFFLINE  

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Posted Wed Aug 9, 2017 9:34 AM

The thing that scares me about Pokey alternatives is that we are still finding ways of using the chip that may not work unless 100% compatibility is maintained. I think there are still a lot of Pokeys out there since they were used by all divisions of Atari and were put into cartridges. It wouldn't surprise me if a warehouse of 7800 Ballblazers turned up some day.


Agreed on the unknown compatibility issues that an FPGA version could suffer from. But not so much a problem if new chips can be fabricated from the original plans.

NOS surfacing in large numbers could also be a game changer. I'm just hoping if that happens people aren't greedy and the price per chip comes down to a more reasonable level like $5 a piece, or perhaps a discount when buying 2 or more.

- Michael

Edited by mytekcontrols, Wed Aug 9, 2017 9:35 AM.


#23 GlowingGhoul OFFLINE  

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Posted Wed Aug 9, 2017 10:02 AM

LOL, if Brad at Best sees this thread, expect prices to double immediately!



#24 mytekcontrols OFFLINE  

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Posted Wed Aug 9, 2017 10:37 AM

LOL, if Brad at Best sees this thread, expect prices to double immediately!

 

Rumor has it that Brad just found a bunch more Pokeys in his warehouse recently, that he didn't know he had.

 

- Michael



#25 ricortes OFFLINE  

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Posted Wed Aug 9, 2017 11:01 AM

Pretty much any solution will be a kludge. Problem among many problems is 5 volt is going obsolete. That means everything from glue logic to existing chips that are no longer manufactured like the MMU will all need logic level conversion. When I say 5 volts is becoming obsolete, I'm as serious as a broken leg. I just went through a round of 3.3 volt regulators and logic level shifter chips on my latest project to mix 5 volt and 3.3 volt operating levels. Everything you say about POKEY chips running out will eventually be said for 5 volt FPGA. 






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