10NES

10NES chip from Super Mario Bros. / Duck Hunt cartridge

The 10NES system is a lock-out system designed for the North American and European versions of the Nintendo Entertainment System (NES) video game console. Various companies found ways to bypass the authorization chip.

Design

The system consisted of two parts, a microchip in the NES that would check the cartridge in the system for authentication, and a microchip in the cartridge that would give the 10NES code upon demand. If the cartridge did not provide the authentication, then the 10NES would reset the CPU during every cycle until a game with the authorization chip was inserted. The constant resetting of the CPU would stop the NES from booting up. However in some instances, the 10NES has been prone to reset the CPU if it fails to authenticate a licensed cartridge. The 10NES was patented under U.S. patent 4,799,635 and the source code was copyrighted; only Nintendo could produce the authorization chips. The patent covering the 10NES expired on January 24, 2006, although the copyright is still in effect.

The 10NES chip was only installed in the model NES-001 Control Deck, not the model NES-101.

Circumvention

Most unlicensed companies created circuits that used a voltage spike to knock the authentication unit in the NES offline.

A few unlicensed games released in Europe and Australia (such as HES games) came in the form of a dongle that would be connected to a licensed cartridge, in order to use that cartridge's 10NES lockout chip for authentication.

Tengen (an Atari Games subsidiary) took a different tactic: the corporation obtained a description of the code in the lockout chip from the United States Patent and Trademark Office by claiming that it was required to defend against present infringement claims in a legal case. Tengen then used these documents to design their Rabbit chip, which duplicated the function of the 10NES. Nintendo sued Tengen for these actions. The court found that Tengen did not violate the copyright for copying the portion of code necessary to defeat the protection with current NES consoles, but did violate the copyright for copying portions of the code not being used in the communication between the chip and console. Tengen had copied this code in its entirety because future console releases could have been engineered to pick up the discrepancy. On the initial claim, the court sided with Nintendo on the issue of patent infringement, but noted that Nintendo’s patent would likely be deemed obvious as it was basically U.S. patent 4,736,419 with the addition of a reset pin, which was at the time already commonplace in the world of electronics. Therefore, while Nintendo was the winner of the initial trial, before they could actually enforce the ruling they would need to have the patent hold up under scrutiny, as well as address Tengen’s antitrust claims. Before this occurred, the sides settled.

A small company called RetroZone, the first company to publish games on the NES in over a decade, uses a multi-region lockout chip for NTSC, PAL A, and PAL B called the Ciclone which was created by reverse engineering Tengen's "Rabbit" chip. It is the only lockout chip in existence that will allow games to be played in more than one region. It is intended to make the games playable on the original NES-001 hardware that uses the 10NES lockout chip and the two other regions - the other region free alternative would be the top-loading NES, which does not feature the lockout chip. The Ciclone chip is the first lockout chip to be developed after the patent for the 10NES had expired.

Because the 10NES in the model NES-001 Control Deck occasionally fails to authenticate legal cartridges, a common modification is to disable the chip entirely by cutting pin 4 on the Control Deck's internal 10NES lockout chip.

See also

• CIC (Nintendo)
• Regional lockout
• Lock-out chip

References

• Kevin Horton. "The Infamous Lockout Chip." Accessed on August 22, 2010.
• U.S. Court of Appeals, Federal Circuit. “Atari Games Corp. v. Nintendo of America Inc..” Digital Law Online. Accessed on April 19, 2006.
• Patent Arcade "Case: Atari v. Nintendo (N.D. Cal. 1993) [C,P] Atari Games Corp. v. Nintendo of America, Inc. 30 U.S.P.Q.2d 1401 (N.D. Cal. 1993) (Atari II)." Accessed on July 12, 2006
• "Ed Logg (Atari) interview" discussing Tengen lock chip
• US 4799635  Nintendo patent for "determining authenticity of an external memory".
• US 5004232  Macronix patent for "game cartridge security circuit" that causes the Nintendo "game console to accept the cartridge".
• Ciclone lockout chip Information from RetroZone
• Disabling the NES "Lockout Chip (Archived 2009-04-29) (rev. 0.5 26-Dec-97)