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View topic - FCRs, Bankswitching and The Ninja...

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  • Joined: 21 Apr 2000
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FCRs, Bankswitching and The Ninja...
Post Posted: Sat May 27, 2000 6:02 pm



I've already posted to the main forum about this, but Zoop pointed out it may be more relevant here...

I discovered that my copy of The Ninja has a standard ROM with a separate IC, the 315-5208, to handle bank-switching. I was therefore able to modify the cartridge to take a standard 1MBit EPROM onto which I can put any 128k game.

Commercial games seem to be fine; I've tried Heliophobe's Tetris demo, though, and it will only work on a Game Gear or Mega Drive, not a real Master System. The SMS will always default to the built-in game (Alex Kidd). A BIOS issue presumably?

I should point out that my Ninja cartridge is an old one (with the standard Philips screws) - it's possible that the newer ones contain a single, bankswitched ROM instead. It's certainly worth a look, though! It may be that all games of a similar vintage have the same arrangement.

Mike


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Post Posted: Sat May 27, 2000 9:03 pm

Quote
> I discovered that my copy of The Ninja has a standard ROM with a separate IC, the 315-5208, to handle bank-switching. I was therefore able to modify the cartridge to take a standard 1MBit EPROM onto which I can put any 128k game.

This is interesting, I have a copy of Action Fighter that is
identical to the picture you posted. I never thought anything
about it, because the ROM chip is the same as the kind found
in other single chip games.

Could you explain what changes need to be made so the board
accepts EPROM's? I don't even have an EPROM programmer, (I'd
imagine they are terribly expensive) but I'd do anything to
run some test programs on a real SMS or Mega Drive.


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Post Posted: Sat May 27, 2000 9:36 pm
Quote
> This is interesting, I have a copy of Action Fighter that is
> identical to the picture you posted. I never thought anything
> about it, because the ROM chip is the same as the kind found
> in other single chip games.

Hmm... my Action Fighter is a single chip cart (dated 1991) - perhaps only the earlier copies of these games have a separate chip for bankswitching?

Just out of interest - does your copy of Action Fighter have normal (Philips type) screws or the more common Sega security screws?

As for the ROMs, I've noticed that "The Ninja" ROM has the part no. 831000. All the other 28 pin SMS ROMs I've seen (including my copy of Action Fighter) say 831001. Make of that what you will :)

Quote
> Could you explain what changes need to be made so the board
> accepts EPROM's? I don't even have an EPROM programmer, (I'd
> imagine they are terribly expensive) but I'd do anything to
> run some test programs on a real SMS or Mega Drive.

EPROM programmers need not be expensive - how does 15 pounds (UK) sound? Have a look at my DIY EPROM projects page :)

As for the changes, here's how to map the 28 pin 831000 ROM socket to a 32 pin 1 MBit EPROM, which is what I've done...

ROM pin EPROM pin
1-14 3-16
15-21 17-23
23-28 25-30
22 2

Connect pin 24 of the EPROM to GROUND, and pins 1, 31 and 32 of the EPROM to +5v.

Mike

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EPROM pins
Post Posted: Sat May 27, 2000 9:47 pm
Ah. Apologies if that wasn't terribly clear:

ROM pins 1-14 go to EPROM pins 3-16.
ROM pins 15-21 go to EPROM pins 17-23.
ROM pins 23-28 go to EPROM pins 25-30.
ROM pin 22 goes to EPROM pin 2.

Mike :)
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Post Posted: Sat May 27, 2000 11:14 pm

Quote
> Hmm... my Action Fighter is a single chip cart (dated 1991) - perhaps only the earlier copies of these games have a separate chip for bankswitching?

This could very well be the case - my Action Fighter is dated 1986.

Quote
> Just out of interest - does your copy of Action Fighter have normal (Philips type) screws or the more common Sega security screws?

It has normal screws. In fact, all US SMS games I've seen, even more recent
ones like Strider and Golden Axe Warrior, use them.

Quote
> As for the ROMs, I've noticed that "The Ninja" ROM has the part no. 831000. All the other 28 pin SMS ROMs I've seen (including my copy of Action Fighter) say 831001. Make of that what you will :)

The Action Fighter ROM is also part # 831000. Probably other old games are the same.

Quote
> EPROM programmers need not be expensive - how does 15 pounds (UK) sound? Have a look at my DIY EPROM projects page :)

That's my kind of pricing. :)

Is supporting a 1 Mbit EPROM as simple as hooking up the
extra lines from the high counter to the address lines on the
EPROM socket? I noticed the ones at zws.com supported
only 16k/32k/64k sizes.

Quote
> As for the changes, here's how to map the 28 pin 831000 ROM socket to a 32 pin 1 MBit EPROM, which is what I've done...

Alright, sounds simple enough. Action Fighter is a pretty
terrible game, so if I destroy the cart in the process, I'm
not losing anything. ;)



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Post Posted: Sun May 28, 2000 9:59 am



Quote
>
> > Hmm... my Action Fighter is a single chip cart (dated 1991) - perhaps only the earlier copies of these games have a separate chip for bankswitching?

> This could very well be the case - my Action Fighter is dated 1986.

> > Just out of interest - does your copy of Action Fighter have normal (Philips type) screws or the more common Sega security screws?

> It has normal screws. In fact, all US SMS games I've seen, even more recent
> ones like Strider and Golden Axe Warrior, use them.

That's disappointing! But there may be another way to tell, without actually opening up the cartridge. Take a look at the picture above, and at the edge connector of your Action Fighter cart. Most SMS carts I've seen have the brown coloured PCB pictured right, but my Ninja cart has a whitish coloured PCB. This may be an indicator of an older (dual chipped) cartridge.

Quote
> > EPROM programmers need not be expensive - how does 15 pounds (UK) sound? Have a look at my DIY EPROM projects page :)

> That's my kind of pricing. :)

> Is supporting a 1 Mbit EPROM as simple as hooking up the
> extra lines from the high counter to the address lines on the
> EPROM socket? I noticed the ones at zws.com supported
> only 16k/32k/64k sizes.

ZWS's EPROMr2 actually supports 8kbyte through 512kbyte devices - the 27010 (a 128k EPROM) is the one to use (or 27c1001, a close equivalent).

My project was simply to add 1Mbyte EPROM support to the EPROMr2, in order to burn firmware for my DVD player. This isn't needed for the SMS, obviously (max cart size is 512k), so the original EPROMr2 design and software is fine. There's a link to it below.

Quote
> > As for the changes, here's how to map the 28 pin 831000 ROM socket to a 32 pin 1 MBit EPROM, which is what I've done...

> Alright, sounds simple enough. Action Fighter is a pretty
> terrible game, so if I destroy the cart in the process, I'm
> not losing anything. ;)

Heh, fair enough :) I'd have some misgivings if it was a Phantasy Star though...

Mike



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Pinout for 315-5208 paging chip
Post Posted: Sun May 28, 2000 5:19 pm



This is what I've figured to be the pinout of the 315-5208 I've found in my Ninja cartridge. Bad news is it would seem that 128k is the limit for this particular chip... but perhaps 256k and 512k variants exist?

I'll also have a look at the second chip inside my Bubble Bobble cart, but I suspect that's something entirely different.

Mike
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Post Posted: Sun May 28, 2000 6:26 pm

Quote
> That's disappointing! But there may be another way to tell, without actually opening up the cartridge. Take a look at the picture above, and at the edge connector of your Action Fighter cart. Most SMS carts I've seen have the brown coloured PCB pictured right, but my Ninja cart has a whitish coloured PCB. This may be an indicator of an older (dual chipped) cartridge.

You're absolutely right. My Action Fighter cart has a lighter
colored area under the edge connectors, and the other single
chip carts are more brownish.

I also noticed that my Penguin Land cart, dated 1987, is like
this. It has a 28 pin ROM just like Action Fighter, but
a *much* larger chip to handle bankswitching (315-5235), and
then another one that is most likely the battery backed RAM.

Also, one of the Phantasy Star carts I have uses the same
chip for bankswitching, has an apparently normal ROM, but
is on the brown kind of board you mentioned. Go figure.
It was dated 1987 too.

Quote
> ZWS's EPROMr2 actually supports 8kbyte through 512kbyte devices - the 27010 (a 128k EPROM) is the one to use (or 27c1001, a close equivalent).

I just so happen to have two 128k EPROM's labled '27C10000', is that a close enough match or not really?


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Post Posted: Sun May 28, 2000 7:08 pm
Quote
>
> > That's disappointing! But there may be another way to tell, without actually opening up the cartridge. Take a look at the picture above, and at the edge connector of your Action Fighter cart. Most SMS carts I've seen have the brown coloured PCB pictured right, but my Ninja cart has a whitish coloured PCB. This may be an indicator of an older (dual chipped) cartridge.

> You're absolutely right. My Action Fighter cart has a lighter
> colored area under the edge connectors, and the other single
> chip carts are more brownish.

> I also noticed that my Penguin Land cart, dated 1987, is like
> this. It has a 28 pin ROM just like Action Fighter, but
> a *much* larger chip to handle bankswitching (315-5235), and
> then another one that is most likely the battery backed RAM.

> Also, one of the Phantasy Star carts I have uses the same
> chip for bankswitching, has an apparently normal ROM, but
> is on the brown kind of board you mentioned. Go figure.
> It was dated 1987 too.

Hmm... I'd like to see these boards as well!

My theory on the chip you mentioned is that it can handle bankswitching for 128k of ROM in addition to battery backed RAM. This is the configuration of Penguin Land. It's possible that your Phantasy Star has a bankswitched ROM and just uses this chip to page in the battery backed RAM.

If the chip can handle paging for 512k ROM as well as battery backed RAM, on the other hand, then it's a lot more versatile than the one used in The Ninja, etc!

What does your other copy (or copies) of Phantasy Star look like?

Another "strange" chip I've seen is the 315-5365, which is used in Bubble Bobble. I doubt that this has anything to do with bank-switching, but I'd like to find out what it does!

Quote
> > ZWS's EPROMr2 actually supports 8kbyte through 512kbyte devices - the 27010 (a 128k EPROM) is the one to use (or 27c1001, a close equivalent).

> I just so happen to have two 128k EPROM's labled '27C10000', is that a close enough match or not really?

Yep, they should be fine - all 27 and 27c variants should be supported. Ones to avoid are 27vXXX - the v signifying a low voltage variant.

Mike
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Post Posted: Sun May 28, 2000 9:23 pm

Quote
> If the chip can handle paging for 512k ROM as well as battery backed RAM, on the other hand, then it's a lot more versatile than the one used in The Ninja, etc!

This could be the case. The chip has 42 pins, most all of
which are used. Also, the ROM's in both cartridges don't
have the same markings that the ones with built-in paging
hardware do, so perhaps they use normal ROM's.

Quote
> What does your other copy (or copies) of Phantasy Star look like?

There's a newer one marked 1988 with the battery mounted on
the back, for some reason, and not at the two slots where
the battery should go. The other one is older, and I think
had a slightly different orientation of the chips, but I don't
have it handy to check at the moment. Gameplay was identical
in both versions.

One other neat thing - it turns out the 315-5235, which
both Penguin Land and Phantasy Star use, is also listed as
being in the 'Mega Tech' arcade hardware. So maybe there are
other SMS based arcade games besides the System E board.

Quote
> Yep, they should be fine - all 27 and 27c variants should be supported. Ones to avoid are 27vXXX - the v signifying a low voltage variant.

Great, guess I saved myself some money then. :)


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Post Posted: Mon May 29, 2000 8:37 am
Quote
>
> > If the chip can handle paging for 512k ROM as well as battery backed RAM, on the other hand, then it's a lot more versatile than the one used in The Ninja, etc!

> This could be the case. The chip has 42 pins, most all of
> which are used. Also, the ROM's in both cartridges don't
> have the same markings that the ones with built-in paging
> hardware do, so perhaps they use normal ROM's.

If this is the case, that's a great find! I have to find myself a copy of Penguin Land and check it out for myself :)

Incidentally, the chip in Bubble Bobble is a 42-pin as well, but I don't know if it's related. I'll try to extract the ROM and read it.

Mike
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Brian
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Post Posted: Mon May 29, 2000 5:04 pm
Do you think you could write some kind of tutorial on how to set this stuff up from the beginning?

I'd be interested in having a system set up like that, but I really wouldn't know where to start, and exactly what to do.

Brian
 
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Post Posted: Tue May 30, 2000 5:47 pm
Quote
> Do you think you could write some kind of tutorial on how to set this stuff up from the beginning?

> I'd be interested in having a system set up like that, but I really wouldn't know where to start, and exactly what to do.

I'm working on it. :)

Mike
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drpepper
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Post Posted: Sat Jun 03, 2000 4:36 am
Thank you so much! I'll be looking forward to reading that.

Quote
> > Do you think you could write some kind of tutorial on how to set this stuff up from the beginning?

> > I'd be interested in having a system set up like that, but I really wouldn't know where to start, and exactly what to do.

> I'm working on it. :)

> Mike
 
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