BIOS RAM locations

Furrtek — Tue, 08 Sep 2026 08:43:23 GMT

Game Related

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Magician Lord

Furrtek — Tue, 08 Sep 2026 05:23:09 GMT

← Older revision		Revision as of 07:23, 8 September 2026
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	Uses no custom chips.		Uses no custom chips.

			The letter G of the "MAX 330 MEGA" text is slightly fucked up.

	[[Category:Games]]		[[Category:Games]]

NEO-PCM2

Furrtek — Sat, 05 Sep 2026 18:35:46 GMT

← Older revision		Revision as of 20:35, 5 September 2026
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	\|pkg=QFP120		\|pkg=QFP120
	\|manu=fujitsu		\|manu=fujitsu
	\|date=~~2001 ?~~		\|date=1999, 2002
	\|gates=		\|gates=
	\|used_on=[[Cartridges]], [[ROM-Only boards]]		\|used_on=[[Cartridges]], [[ROM-Only boards]]
	}}		}}

	Second version of {{Chipname\|PCM}}. [[V ROM]] ~~(de)multiplexer~~, decryption and [[P ROM]] banking chip.		Second version of {{Chipname\|PCM}} which confusingly exists in two forms under the same name. [[V ROM]] demultiplexer, decryption and [[P ROM]] banking chip.

	The decryption algorithm used by emulators ~~may not be~~ perfectly exact, ~~this could be~~ a ~~possible cause of incorrect data~~ in decrypted romsets causing minor audio glitches (Samurai Shodown V "Basara").		The demultiplexing logic is exactly the same as the one found in PCM.

			=Jumpers=

			The ROM and mapping configuration for a given game is set by external jumpers. There are 3 for the V ROMs (JV1 to JV3) and 4 for the P ROMs (J1 to J4).
			These do not appear to affect security functions.

			V ROM mapping uses address bits 20 to 23. There are 4 chip select outputs.

			=Security=

			The security function of the 1999 SNK branded version only performs address descrambling on V ROMs. The Playmore version which came out in 2002 adds a data decryption layer on top, which means both are not interchangeable.

			The decryption algorithm used by emulators currently isn't perfectly exact, which explains the presence of a few corrupt bytes in decrypted romsets causing minor audio glitches (Samurai Shodown V "Basara" sample).

			==SNK version==

			P ROM bank selection is done by writing the 3 lower bits of the [[68k memory map\|port zone]] with A19 high to not affect the V ROM setting. ie. $200000 (word) or $200001 (even) with mirrors up to $2FFFFF.
			Metal Slug 4 for example writes words to $2FFFF0. Todo: how does the bank number map to an address.

			V ROM address scrambling is only done on the 4 lower bits by selectively inverting them depending on the configuration set by the [[68k]] CPU. Bits 4 to 23 go straight through.

			This is set by first writing 7 to the [[68k memory map\|port zone]], the same way P bank 7 would be selected. And then writing the 3 bit configuration value with A19 low.
			Metal Slug 4 for example writes words on startup to the bogus addresses $200000, $208000 and $220000.

			To test:
			{\| class="wikitable"
			\|-
			! V configuration !! VA3 !! VA2 !! VA1 !! VA0
			\|-
			\| 0 \|\| invert \|\| invert \|\| invert \|\| invert
			\|-
			\| 1 \|\| invert \|\| invert \|\| normal \|\| invert
			\|-
			\| 2 \|\| normal \|\| invert \|\| invert \|\| invert
			\|-
			\| 3 \|\| invert \|\| invert \|\| normal \|\| invert
			\|-
			\| 4 \|\| invert \|\| invert \|\| invert \|\| invert
			\|-
			\| 5 \|\| invert \|\| invert \|\| normal \|\| normal
			\|-
			\| 6 \|\| invert \|\| normal \|\| invert \|\| invert
			\|-
			\| 7 \|\| invert \|\| invert \|\| normal \|\| invert
			\|}

			==Playmore version==

			Todo.

			=Games=

	Used by:		Used by:
			* [[Matrimelee]] (Playmore)
	* [[Matrimelee]]		* [[Metal Slug 4]] (SNK)
	* [[Metal Slug 4]]		* [[Metal Slug 5]] (Playmore)
	* [[Metal Slug 5]]		* [[Pochi and Nyaa]] (SNK)
	* [[Pochi and Nyaa]]		* [[Rage of the Dragons]] (SNK)
	* [[Rage of the Dragons]]		* [[Samurai Shodown V]] (Playmore)
	* [[Samurai Shodown V]]		* [[Samurai Shodown V Special]] (Playmore)
	* [[Samurai Shodown V Special]]		* [[SNK vs. Capcom - SVC Chaos]] (Playmore)
	* [[SNK vs. Capcom - SVC Chaos]]		* [[The King of Fighters 2001]] (SNK)
	* [[The King of Fighters 2001]]		* [[The King of Fighters 2002]] (Playmore)
	* [[The King of Fighters 2002]]		* [[The King of Fighters 2003]] (Playmore)
	* [[The King of Fighters 2003]]

	=Pinout=		=Pinout=
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	OpenOffice Draw file: [[File:neo-pcm2.odg]]		OpenOffice Draw file: [[File:neo-pcm2.odg]]

			Does the Playmore version have the same pinout ?

	[[Category:Chips]]		[[Category:Chips]]

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BIOS RAM locations

Magician Lord

NEO-PCM2