about paprium

Discussion of development of software for any "obsolete" computer or video game system.
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aquasnake
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about paprium

Post by aquasnake » Wed Sep 25, 2019 12:34 am

paprium is a home-brew game on sega genesis platform, but never released till now.

i believe that its prototype has been already finished and can run on some emulator pretty well.

but there is something wrong while mass producing, most of cart providers can not design a set of hardware that supporting 80M address accessing.

i designed a full range address accessing expansion chip, supporting another 80M homebrew game of UMKT(ultimate mortal kombat trilogy). maybe can help original designers and let dream come true
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lidnariq
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Re: about paprium

Post by lidnariq » Wed Sep 25, 2019 9:41 am

The SMD 10MB map requires that the cartridge drive /DtAck=B20 when the game reads from memory in the $800000-$9FFFFF region.

However, I tried to build a cartridge that supported this (for UMKT) but it just crashed, so I clearly missed something else.

tepples
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Re: about paprium

Post by tepples » Wed Sep 25, 2019 10:03 am

The 10 MiB map also messes up if a 32X or Sega CD is present, so I would recommend against using it in new productions.

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NOOPr
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Re: about paprium

Post by NOOPr » Wed Sep 25, 2019 10:14 am

tepples wrote:The 10 MiB map also messes up if a 32X or Sega CD is present, so I would recommend against using it in new productions.
There's no way to bank the 10MiB to avoid conflicts with these peripheral addresses?

lidnariq
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Re: about paprium

Post by lidnariq » Wed Sep 25, 2019 10:21 am

Bankswitching is fine, yes. But the 10MB map is a flat map, not bankswitched, which sets it up to collide with the CD (in the $400000-$7FFFFF region) and the 32x (in the $800000-$9FFFFF region).

(edit #1: For example, the 8MB homebrew RPG Pier Solar uses unreasonably complicated bankswitching, dividing the 4MB dedicated for cart memory into eight 512KB individual banking regions)

(edit #2: I just want someone to explain how the UMKT 13MB map is supposed to work)
Last edited by lidnariq on Wed Sep 25, 2019 10:34 am, edited 2 times in total.

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Fisher
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Re: about paprium

Post by Fisher » Wed Sep 25, 2019 10:23 am

Can Megadrive use bankswitching techniques as simple as a latch or a flip flop?
How usefull would that be?

lidnariq
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Re: about paprium

Post by lidnariq » Wed Sep 25, 2019 10:24 am

Yes, some pirate multicarts did.

tepples
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Re: about paprium

Post by tepples » Wed Sep 25, 2019 10:45 am

lidnariq wrote:the 8MB homebrew RPG Pier Solar uses unreasonably complicated bankswitching, dividing the 4MB dedicated for cart memory into eight 512KB individual banking regions)
I was under the impression that Sega's official mapper, used by Capcom's Super Street Fighter II, supported the same "unreasonably complicated" window set despite SSF2 using only a portion of its functionality. According to this description of Sega's mapper, the first window (containing reset vectors among other things) is fixed and the other 7 switchable.

aquasnake
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Re: about paprium

Post by aquasnake » Wed Sep 25, 2019 9:06 pm

PSolar devide 32Mb into 8 banks. init them 0 to 7 after reset

bank0-4 are fixed.

bank5-7 are swapable.

strat
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Re: about paprium

Post by strat » Thu Sep 26, 2019 8:15 pm

lidnariq wrote:Bankswitching is fine, yes. But the 10MB map is a flat map, not bankswitched, which sets it up to collide with the CD (in the $400000-$7FFFFF region) and the 32x (in the $800000-$9FFFFF region).
And apparently the reason GEN Virtua Racing doesn't work with a 32-X attached, though looking at these docs the clash doesn't jump out at me.

https://notaz.gp2x.de/docs/svpdoc.txt
http://devster.monkeeh.com/sega/32xguide1.txt

lidnariq
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Re: about paprium

Post by lidnariq » Thu Sep 26, 2019 8:42 pm

Maaaaaybe either the 32X or the SVP don't treat /DtAck as the open-collector input to the 68k that it should be? (Needed for the 32X in $800000-$9FFFFF range; needed for the SVP in $A15000-$A15FFF range?) So they get in a fight, one of them wins by pulling it up when it shouldn't, and the 68k thus hangs waiting forever for the data bus to become ready?

If this is what's wrong, you should be able to fix it by putting a diode in between the Genesis and the relevant poorly-behaved coprocessor.

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TmEE
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Re: about paprium

Post by TmEE » Fri Sep 27, 2019 6:20 am

32X doesn't pass top slot !DTACK and that's why SVP/Virtua Racing doesn't work, a simple mod will restore compatibility.

aquasnake
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Re: about paprium

Post by aquasnake » Thu Oct 17, 2019 6:58 pm

DO NOT PURCHASE THIS CART FROM ALIEXPRESS

its fake and inferior.


for some reason, some fakes dont support the consoles which manufacture model are after VA6 GENESIS ONE.

due to above situations, it runs to a logo screen and then crashes there, the VDP can not parse address and the cart DOES NOT fix the logic either.

be careful in purchasing the fake one, u shall ask for a refund.

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Banshaku
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Re: about paprium

Post by Banshaku » Sun Oct 20, 2019 5:28 pm

Hmmm.... I have been talking about "that" game a lot on some French discord recently and first:

- it was never released
- the author is missing in action
- people are still waiting for it but not expecting to come out

so I have no idea what you are expecting by buying a cart like that on aliexpress since it's obviously a fake and supposedly the original cart was going to have a special chip for music or whatever (maybe another one of those "stories" that made the game delayed and never released, who knows how much it was real).

So this thread should be closed anyway.

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