NEO-PVC: Difference between revisions

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[[File:brd_pvc.jpg|thumb|NEO-PVC chip. Picture courtesy of [[http://www.mvs-scans.com MVS-Scans]].]]
[[File:brd_pvc.jpg|thumb|NEO-PVC chip. Picture courtesy of [[http://www.mvs-scans.com MVS-Scans]].]]


QFP144 chip connected to the [[68k]] program ROMS in [[ROM-Only boards|ROM-only]] arcade boards and late cartridges like [[SVC Chaos]] or [[Samurai Shodown 5]].
QFP144 chip connected to the [[P ROM]]s in [[ROM-Only boards|ROM-only]] arcade boards and late cartridges like [[SVC Chaos]] or [[Samurai Shodown 5]]. Used for bankswitching and security.


May be used for on-the-fly decryption.
Has 8KiB of integrated RAM organized as 4096 16bit words.


From [[http://mamedev.org/source/src/mame/machine/neoprot.c MAME's source]]:
Accesses are made in the $2FE000~$2FFFFF range:
<pre>
COMBINE_DATA(&state->m_pvc_cartridge_ram[offset] );
if (offset == 0xff0)
pvc_prot1(space->machine());
else if(offset >= 0xff4 && offset <= 0xff5)
pvc_prot2(space->machine());
else if(offset >= 0xff8)
pvc_write_bankswitch(space);
</pre>
[[Category:Chips]]
[[Category:Chips]]

Revision as of 23:39, 29 March 2012

NEO-PVC chip. Picture courtesy of [MVS-Scans].

QFP144 chip connected to the P ROMs in ROM-only arcade boards and late cartridges like SVC Chaos or Samurai Shodown 5. Used for bankswitching and security.

Has 8KiB of integrated RAM organized as 4096 16bit words.

From [MAME's source]:

Accesses are made in the $2FE000~$2FFFFF range:

	COMBINE_DATA(&state->m_pvc_cartridge_ram[offset] );
	if (offset == 0xff0)
		pvc_prot1(space->machine());
	else if(offset >= 0xff4 && offset <= 0xff5)
		pvc_prot2(space->machine());
	else if(offset >= 0xff8)
		pvc_write_bankswitch(space);