Saving Custom Chip

KidVidiot

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Is there a way these days to save custom chips from disappearing into oblivion? Can you rip them or download them or something in order to burn new ones? Basically if the custom chip on my pcb is still working, is there anything I can do to create another one in case it ever stops working?
 
depending on the popularity of the game will determine if reproduction custom chips are made. they get the name custom chip because they were designed with unique circuitry that you couldn't get from an off the shelf chip.

I think Gorf's are being reproduced, and some of Galaga's (if not all, not sure, which means Dig Dug's too)

the Williams custom chips are beginning to fail now. Capcom's CPS1 hardware I'm guessing the failures are in their ASICs.
 
depending on the popularity of the game will determine if reproduction custom chips are made. they get the name custom chip because they were designed with unique circuitry that you couldn't get from an off the shelf chip.



I think Gorf's are being reproduced, and some of Galaga's (if not all, not sure, which means Dig Dug's too)



the Williams custom chips are beginning to fail now. Capcom's CPS1 hardware I'm guessing the failures are in their ASICs.



So it's not as simple as reading the data off the working chip and burning it onto new ones?
 
The older custom chips are ASICs. They are proprietorially designed ICs created by a company for a specific product or application. Unlike TTL and CMOS so-called standard ICs, their contents were not made public. However, like TTL/CMOS standard ICs, the custom ICs have hard logic inside them. They don't have a programming/reading interface at all. You cannot read them any more than you could read a TTL chip such as a 7400 Quad 2-input NAND gate.

In general, modern replacements are not actually copies of the original ASICs. They are not ASICs themselves. Producing such would be cost prohibitive at low volumes. Modern replacements are logical equivalents produced by programming a general purpose programmable array-style off-the-shelf IC to perform equivalent functions. In theory, these replacements could be read for the purposes of duplication, but as previously stated by someone else, they are usually locked to protect the originator's proprietary and/or intellectual property.

For example, if you could get your hands on the original masks for the Atari POKEY chip and if you could find a factory that can still produce ICs using the same processes used with those masks, then you could reproduce the POKEY ASIC. This would be a very expensive endeavor even if you could acquire the masks for free. A much cheaper solution would be to create equivalent functionality in a logical programming language such as Verilog or VHDL and use it to program a modern IC. You would mount that new IC onto a custom PCB to adapt it to physically fit into a DIP-40 socket. It's 98% safe to say that anyone who manages to create a perfectly functionally equivalent device after a massive investment of work will certainly lock it.

With respect to reverse-engineering a specific chip, there's lot of methods that can be applied but no single method will work on all targets. Some devices can be figured out easily. Some are immensely complex. Complex enough in fact that they may never be duplicated. While deciphering any particular IC isn't necessarily impossible, it might not be cost effective in terms of time and money to do so given the size of the target market that might benefit from doing so.

Bill B.
 
well, I would have to think with MAME emulating hardware, they have to have some knowledge of how a lot of these custom parts work. otherwise playing Atari, Street Fighter 2, Mortal Kombat, or Namco-based games would be impossible.
 
the Williams Custom Chip in particular is like a much larger application of the Special Chips that Joust and Robotron had in that it's addressing heavy quantities of rom data to interface with the ram. and that was 32-bit CPU hardware, so those have to be incredibly intricate.

considering I've had 2 NARC main boards with bad customs and another guy recently with a bad Smash TV custom, those are probably going to start fizzling out more.

the Namco customs from Galaga in particular have the legs just fall off. probably Gorf too, not sure why that had custom hardware, that was a straight Midway game.

we should enjoy this life while it lasts. in about 10 years it's going to be very ugly.
 
well, I would have to think with MAME emulating hardware, they have to have some knowledge of how a lot of these custom parts work. otherwise playing Atari, Street Fighter 2, Mortal Kombat, or Namco-based games would be impossible.

^ this. for those who say repro'n or fpga'n custom IC's is impossible... how the fsck did they do it with mame emulation?!
 
Not as simple as copying data.
You can not copy a "and gate", "Nand gate", "or gate" or "nor gate" and dump it into a EPROM.
You can not read a CPU Mpu dma pio or pia chip and dump it in a EPROM.

Can you duplicate custom chips? Yes but it not a cheap nor easy.

Maybe you can look at a clone board and see how they went around the custom ic chips.
 
well, I would have to think with MAME emulating hardware, they have to have some knowledge of how a lot of these custom parts work. otherwise playing Atari, Street Fighter 2, Mortal Kombat, or Namco-based games would be impossible.
^ this. for those who say repro'n or fpga'n custom IC's is impossible... how the fsck did they do it with mame emulation?!
The problem is that MAME doesn't necessarily emulate exactly how a custom chip runs. There's a huge difference between emulating the high level functionality of a chip vs. making it behave exactly the same as the chip, down to the every signal and clock cycle accuracy.

Take for example a custom graphics chip that has the capability to draw sprites, perform rotations, scaling, etc. MAME will simply look at the instruction written to the graphics chip and say that's a 90 degree rotation with 2x scale, so draw it to the MAME graphics framebuffer with those operations done.

To put that in an FPGA as a drop-in replacement, you'd need to first of all create the logic to do the scaling and rotation (instead of simply calling a function that uses your 3GHz PC CPU to calculate it), as well as doing all the memory addressing to draw it to the physical RAM chips, taking commands from the CPU, etc... and do it all with the exact same timing as the original chip. If something isn't quite perfect in MAME it runs just a bit faster, slower, lags, etc... on real hardware, the consequences of inaccurate timing will likely be much worse (collisions on the bus, data not getting written, operations happening out of order, etc).

If MAME was a circuit simulator instead of emulator, you could just take a piece of circuitry and drop it in real hardware... but then it'd be so slow that most games wouldn't be playable, and most pieces of hardware wouldn't be emulated, because of the difficulty to create circuit accurate emulations.

Custom or not, you can get an understanding of the hardware from MAME, but you won't necessarily get the details of the hardware implementation from it (i.e. even for something like a standard Z80, you couldn't generate a hardware replacement just from MAME).

DogP
 
Atari POKEY is "emulated". and I thought I saw AtariAge has the HOKEY POKEY replacement. but seemingly, no such monster exists. so we have to scalp 7800s for them, at $25 a piece.

what did I miss? :p
 
and some of Galaga's (if not all, not sure, which means Dig Dug's too)

I have repro's of all the Galaga customs, which are shared with Dig Dug and Bosconian. Bosco had just one type of extra custom (IIRC) plus pole position shared some of the same ICs.

- James
 
I Like it ! That's taking re-pinning seriously !

Fixed that chip in 2013, wrote up my work in 2014. Now, approaching 2017, Galaga still works. Sometimes there just isn't a replacement yet and we have no choice.

With that said, Jrok, you've been a great asset to the whole arcade the community. I've always admired the work you've done. Thank you.
 
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Not as simple as copying data.
Maybe you can look at a clone board and see how they went around the custom ic chips.

Yes, I've been working on repairing a few bootlegs recently and it's fascinating to see how those scary custom asics are often replicated with just a handful of 74 TTL chips. That said, designing replacements would be very difficult and time consuming.
 
Hard core chip repair. love it.

I haven't sen where a 6 foot circumfernece rubber band is used though.
I also didn't see pliers that were 3 inches wide (quarter of a foot) in use.
And I don't think I've ever seen a pair of needle nose pliers with 1.2 inch wide tips !

:) :) :)

Maybe you meant " instead of ' :)
 
Just a suggestion on the chip repair for the next time, I did the exact same sort of repair to a 40-pin custom IC, except that I soldered the re-pinned chip to the new socket before potting it. The epoxy that I used was JB-Weld (2-part) which gets a lot harder than translucent 5-min epoxy and gives you more time to work with it. It's also cheaper and smells a lot less. When JB-Weld is warmed up, it flows very well and allows the bubbles to get out. At 60°C, it cures in a about an hour as opposed to several hours at room temp. By potting it after assembly, the entire thing becomes one nice block. The natural color of JB-Weld is gray so I spray-painted the block black and then applied a laser-printed laminated label. It actually looked pretty nice afterward. Also, JB-Weld can be sanded or reworked easily and it bonds to metal and plastic very well. Now I wish I had pictures of it but I sold the machine years ago. I also did this repair once on a DIP-16 BPROM that I could not easily replace.

Thanks for presenting the repair technique in such detail. Very well done!

Bill B.
 
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