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CPS2 PAL (BGSA5)

mathewbeall

mathewbeall

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Hi Folks!

I need one of these chips - to get my CPS2 A board up and working again. I am having trouble finding anything out about this chip - is it a EPROM that I can program?

Matt
 
I'm not sure that I've fully understood the question - sorry If Im telling you stuff you already know.

Good background here
https://www.arcade-projects.com/threads/can-someone-school-me-on-pals-and-gals.4029/page-3

PAL and GAL are in my mind like mask rom and EPROM (I think in real life its more complicated) but the point is if you want to write your own you'll need a dump of the PAL converted to a a suitably formatted .jed file, that can be written to a GAL chip
https://www.digikey.co.nz/en/products/detail/microchip-technology/ATF16V8B-15PU/1118926

So think BGS-A5 is going to equate to PAL-A

The revision (5) shouldn't matter as far as I know, but if it must be A5 page here
https://wiki.pldarchive.co.uk/index.php?title=BGS-A5

Which has been recreated by the awesome @WydD and can be downloaded here
https://wiki.pldarchive.co.uk/index.php?title=Alien_vs_Predator

So if it were me I'd be downloading the converted .jed file for the GAL that suited my needs, and writing it to a PAL like ATS16V8B
 

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hatmoose said:
I'm not sure that I've fully understood the question - sorry If Im telling you stuff you already know.

Good background here
https://www.arcade-projects.com/threads/can-someone-school-me-on-pals-and-gals.4029/page-3

PAL and GAL are in my mind like mask rom and EPROM (I think in real life its more complicated) but the point is if you want to write your own you'll need a dump of the PAL converted to a a suitably formatted .jed file, that can be written to a GAL chip
https://www.digikey.co.nz/en/products/detail/microchip-technology/ATF16V8B-15PU/1118926

So think BGS-A5 is going to equate to PAL-A

The revision (5) shouldn't matter as far as I know, but if it must be A5 page here
https://wiki.pldarchive.co.uk/index.php?title=BGS-A5

Which has been recreated by the awesome @WydD and can be downloaded here
https://wiki.pldarchive.co.uk/index.php?title=Alien_vs_Predator

So if it were me I'd be downloading the converted .jed file for the GAL that suited my needs, and writing it to a PAL like ATS16V8B
Click to expand...
As I need a PAL-G for a CPS2 B-Board, looking at Digikey there is ATF16V8B-15PU and also ATF16V8BQL-15PU
Is there a difference with the one which has the QL?
Or which should be the correct to program the PAL-G .jed to?
 
I didn't really know the answer to this either, have never worked with the "QL" variant, I didn't actually know that it existed until you mentioned it.

Why would someone pay 50 cents more for a seemingly identical chip? Fun (for me) data sheet detective time.

Atmel were in terminal decline by 2014 and were bought out by microchip just a few years later, and the data sheet for ATF16V8BQL is a great example of how to write Worse Than Useless documentation.
https://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-0364-PLD-ATF16V8B-8BQ-8BQL-Datasheet.pdf
But there was a fun little engineering teaser in there saying that the BQ had been discontinued and replaced by the B and BQL. Normally when engineers go out of their way to present a factoid like that its because they are trying to help.

And they were! The BQ data sheet is an absolute gold-mine of useful information, basically our anonymous engineer was saying "this new datasheet is garbage, check out the older one for all the useful stuff"

And here it is, lovingly crafted, carefully thought out, beautifully explained. I suspect that the guy who invented this product wrote the datasheet - its an expression of love
https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/2493/ATF16V8B, BQ, BQL.pdf

So from the older data sheet I learned that the QL variant is for low power consumption, and specifically low standby power applications.
Can we use a BQL in place of the standard B? Absolutely yes.
Is it worth paying an extra 50 cents for? Not in any way whatsoever

So TL;DR id be using the ATF16V8B-15PU for this application

If you need an easy download link for the PAL-G the awesome Porchy has recreated here
https://wiki.pldarchive.co.uk/index.php?title=Street_Fighter_Alpha/Zero_3
 
hatmoose said:
If you need an easy download link for the PAL-G the awesome Porchy has recreated here
https://wiki.pldarchive.co.uk/index.php?title=Street_Fighter_Alpha/Zero_3
Click to expand...

That should be the same as the dump for the PAL-G in this ZIP you uploaded here right?

hatmoose

Post in thread 'CPS2 PAL (BGSA5)'

I'm not sure that I've fully understood the question - sorry If Im telling you stuff you already know.

Good background here
https://www.arcade-projects.com/threads/can-someone-school-me-on-pals-and-gals.4029/page-3

PAL and GAL are in my mind like mask rom and EPROM (I think in real life its more complicated) but the point is if you want to write your own you'll need a dump of the PAL converted to a a suitably formatted .jed file, that can be written to a GAL chip
https://www.digikey.co.nz/en/products/detail/microchip-technology/ATF16V8B-15PU/1118926

So think BGS-A5 is...
  • Like
 
Functionally identical yes - there is a philosophical difference between a dump and a brute-force reimplementation. I've never done a dif on the files to see if they are actually byte-for-byte identical, but yes, for practical purposes they are the same.
 
hatmoose said:
Functionally identical yes - there is a philosophical difference between a dump and a brute-force reimplementation. I've never done a dif on the files to see if they are actually byte-for-byte identical, but yes, for practical purposes they are the same.
Click to expand...
I compared them in ChatGPT and response was they are byte-perfect
 
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