NEO-CMC

From NeoGeo Development Wiki
Revision as of 12:08, 2 December 2011 by Cyberwillis (talk | contribs)
Jump to navigation Jump to search
"CMC42" chip on a MVS cartridge. Picture courtesy of [MVS-Scans].

The most "basic" information published can be found at [MAME:neocrypt.c]

The detailed information bellow:

The NEO-CMC Chip is a Asic (Application Specific Integrated Circuit). This device can be programmed only once after the manufaturer had created severals stable prototypes using FPGA (Field Programmable Gate Array) or another technology. And decide to create a Custom Chip

To get a intuition about costs related read this: [FPGA vs ASICs production and design]

So SNK had planned to put his next protection and try to avoid NeoGeo piracy using the NEOCMC algorithm.

The Toshiba as partner of SNK, not only made solution to hold data on it's Mask Roms (TC5xxxx) as used its technology solutions to help SNK try to avoid the Piracy. Toshiba until 1995 had a line of Asics called TC190G series, the evolution can be found here [Toshiba Technology RoadMap].

One of the series of its technology that was best switable to SNK was TC190G series of ASIC.

The series TC190G cannot be found in datasheets anymore, but in past years had these models of chips:

  • TC190G06CF7008
  • TC190G06CF7042
  • TC190G06CF7050

may be more...

Apparently the last two models was used because the number of internal gates was compatible what SNK wanted, to build inside this custom the following logic algorithms:

  • NEO-ZMC
  • NEO-273
  • And a new scrambling system for that interlaces M1 + CX + S1 ROM data


Than, released model of CMC was NEO-CMC42 in the following cartridges:

CART ID TITLE NAME
070 Zupapa
251 King Of Fighters 99
252 Ganryu
253 Garou Mark Of the Wolves
254 Strikers 1945
255 Prehistoric Isle 2
256 Metal Slug 3
259 Bang Bead
260 Nightmare in the Dark
261 Sengoku 3

This version had only S1 and CRoms Encrypted and M1 was in normal condition (unencrypted)

This was just a just a test to see if SNK and Toshiba could be more further in protection

Next SNK just incremented a new scramble and some tests point into M1 to validate the sync decryption and this caused to SNK release the model NEO-CMC50 on the following cartridges:

CART ID TITLE NAME
008 Jockey Grand Prix
257 King Of Figthers 2000
262 King Of Figthers 2001
263 Metal Slug 4
264 Rage of the Dragons
265 King Of Fighters 2002
266 Power Instinct - Matrimele
267 Pochi to Nyaa
268 Metal Slug 5
269 SNK vs Capcom Chaos
270 Samurai Showdown Zero / Samurai Showdown 5
271 King of Fighters 2003
272 Samurai Showdown Zero Special / Samurai Showdown 5 Special

About Jockey Gran Prix, some peoples say this game is not official release but it´s not true. At least its production of the card is official, because they had used the REAL Encryption that cannot be mocked easly. Only the Toshiba and SNK knew the encryption and until today "NO ONE" piracy goes so forensic to mock it. Explanation Later.


File:Brd cmcnoref.jpg
"CMC50"

Also found on ROM-only arcade boards, without the "NEO-CMC" marking.

Pinout

Notes:

  • C_e_D[0-15]: C1/C3/C5/C7 data bus
  • C_o_D[0-15]: C2/C4/C6/C8 data bus
  • CX A[0-21]: C1/C2/C3/C4/C5/C6/C7/C8 address bus
  • Pins 87,88 contains a RC circuit clock driver like in a 8085 with X1 and X2 pinouts
  • Pins 89 and 92 are short circuited in Cartridge board.