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 Post subject: SA1 without SRAM?
PostPosted: Mon Jul 30, 2018 8:09 pm 
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Does somebody know something about SA1 without SRAM? Or have a PCB photo for such carts?

Asking because this post viewtopic.php?f=12&t=17600#p222292 mentions "Pachi-Slot Monogatari - PAL Kougyou Special" having a special "FX-KSS" chip, and I've never heard about any such chip.

As far as I know the game is using a SA1 chip (it is writing to SA-1 ports at address 22xxh) (but don't know if it's using the SA1 cpu anywhere).

The special thing about the game appears to be SRAM related. The cart header contains [FFD6h]=36h which would mean "ROM+SA1+Battery" (=without SRAM/BWRAM). So I guess that it's using battery-backed IRAM (book2 mentions that being possible).

Seeing PCB front+back sides might help to confirm if it's using IRAM with battery. I guess one of the VCC pins (or one of the unused pins) is wired to battery on such carts.


Last edited by nocash on Mon Jul 30, 2018 9:44 pm, edited 1 time in total.

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 Post subject: Re: SA-1 without SRAM?
PostPosted: Mon Jul 30, 2018 8:26 pm 
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I have most of the special chips. I wrote the list. Here is the picture of the board:
Image


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 Post subject: Re: SA-1 without SRAM?
PostPosted: Mon Jul 30, 2018 8:56 pm 
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Thanks! Hmmm, the picture quality is a bit imperfect. I can decipher the SHVC-1L0B-01 board name, but not much more.
MM1026 pin6 should output the battery voltage to one of the SA-1 pins. Can you see where it's connected to?
If I should guess, when adjusting the brightness, there might be a ghostly shadow of a wire that might go from MM1026 pin6 through CB and C5, and then somewhere near SA-1 pin100.


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 Post subject: Re: SA-1 without SRAM?
PostPosted: Mon Jul 30, 2018 9:13 pm 
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Joined: Mon Mar 25, 2013 1:53 am
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Location: Finland
Sorry for the blurry image, its still early morning in here. I got some better pictures with more light now.
It is a bit hard to trace the power with eye, but i measured it and it goes to pin 101 of the SA-1 from C5 (MM1026AF pin 7), and to pin 100 of the SA-1 from pin 6 on MM1026AF (via jump trace under the board).
Thanks for the correction! I will take full responsibility on all the errors on the list. Its mainly copy paste knowledge from various sources.
I'm not expert on Japanese, or any of the code side of this stuff.. :D
Image
Image
(Edit, pin out confusion, still drinking my morning coffee..)


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 Post subject: Re: SA1 without SRAM?
PostPosted: Mon Jul 30, 2018 9:46 pm 
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Thanks for the new photos! So it's SA1 pin101 being the supply input for IRAM (on other carts it's wired to VCC, and they do instead have an additional battery backed external SRAM chip).


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 Post subject: Re: SA1 without SRAM?
PostPosted: Mon Jul 30, 2018 10:31 pm 
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Joined: Mon Mar 25, 2013 1:53 am
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Location: Finland
Sound and seems all good, but its still a bit gibberish for my current understanding :D
Is it OK if i list it under its own section something like this:

Quote:
SA-1 (without SRAM):
==================
Pachi-Slot Monogatari - PAL Kougyou Special - Pachisuro Palusupe (Pachislo Story) (J) Pachinco game.

*The game is using a SA1 chip. It is writing to SA-1 ports at address 22xxh.
But it's not using the SA1 cpu anywhere. The special thing about the game appears to be SRAM related.
The cart header contains [FFD6h]=36h which would mean "ROM+SA1+Battery" (=without SRAM/BWRAM).
So it's using battery-backed IRAM. "SNES Development Manual - Book 2" mentions that being possible
(https://archive.org/details/SNESDevManual).
On other carts it's wired to VCC, and they do instead have an additional battery backed external SRAM chip.


I can also add credits of the info if you want?


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 Post subject: Re: SA1 without SRAM?
PostPosted: Tue Jul 31, 2018 7:15 am 
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That's an interesting board. At a glance the game really doesn't appear to be using any actual SA-1 features at all, so what was the point of using it instead of just a regular SRAM board?


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 Post subject: Re: SA1 without SRAM?
PostPosted: Wed Aug 01, 2018 9:21 am 
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I might suggest two possibilities. The first is copy protection, plain and simple. Does the game run or save when you change the header to a normal cart? The second is that they planned on using the SA-1, but an order of boards in, but they did not have time to implement their intended features for the chip or wound up not needing the features after all. But they were stuck with the board.

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 Post subject: Re: SA1 without SRAM?
PostPosted: Wed Aug 01, 2018 9:33 am 
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As far as I can tell it does run fine without RAM (bsnes-plus' heuristics originally detected it as a regular LoROM cart without SRAM or battery), though I didn't play with it long enough to see exactly how or when it uses the SA-1 IRAM. I don't think there are any gameplay issues aside from likely lack of saving ability.


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 Post subject: Re: SA1 without SRAM?
PostPosted: Thu Aug 02, 2018 9:20 am 
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I added the game to the "official" list on wikipedia with a link to this forum for verification.

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 Post subject: Re: SA1 without SRAM?
PostPosted: Sun Aug 05, 2018 5:14 am 
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Well, the most obvious possibility would be that the SA1 was originally used for the THINK button. And then the game quickly started to wonder why you were playing it - and the developer blocked the AI from using the SA1 functionality in order to prevent it from doing that.

Other theory would be that the PCBs were manufactured for another/unreleased game, and that they got the boards for cheap because nobody else wanted to have them. Or vice-versa: Maybe the coder had shamelessly charged double payment for making a specialist game with coprocessor functions ; )

I's really a bit weird, the SA1 CPU seems to be actually left unused, as well as the variable-length Variable-Length decompression hardware (which would require using the SA1 CPU). One thing that is used is IRAM for the SAVE button (saving seems to be ignored at game start, but going to another building, spending money there, and finding a way to leave the building/menues, returning to home building, and then saving does unlock the Continue option).


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