GENERAL DESCRIPTION

The HCS412 combines patented KEELOQ code hopping technology with bi-directional transponder challenge-and-response security into a single chip solution for logical and physical access control.

When used as a code hopping encoder, the HCS412 is ideally suited to keyless entry systems; vehicle and garage door access in particular. The same HCS412 can also be used as a secure bi-directional transponder for contactless token verification. These capabilities make the HCS412 ideal for combined secure access control and identification applications, dramatically reducing the cost of hybrid transmitter/transponder solutions.

FEATURES

Security

• Programmable 64-bit encoder crypt key

• Two 64-bit IFF keys

• Keys are read protected

• 32-bit bi-directional challenge and response using one of two possible keys

• 69-bit transmission length

• 32-bit hopping code,

• 37-bit nonencrypted portion

• Programmable 28/32-bit serial number

• 60-bit, read protected seed for secure learning

• Two IFF encryption algorithms

• Delayed counter increment mechanism

• Asynchronous transponder communication

• Transmissions include button Queuing information

Operating

• 2.0V to 6.3V operation

• Three switch inputs: S2, S1, S0 – seven functions

• Battery-less bi-directional transponder capability

• Selectable baud rate and code word blanking

• Automatic code word completion

• Battery low detector

• PWM or Manchester data encoding

• Combined transmitter, transponder operation

• Anticollision of multiple transponders

• Passive proximity activation

• Device protected against reverse battery

• Intelligent damping for high Q LC-circuits

• 100 mVPP sensitive LC input

Typical Applications

• Automotive remote entry systems

• Automotive alarm systems

• Automotive immobilizers

• Gate and garage openers

• Electronic door locks (Home/Office/Hotel)

• Burglar alarm systems

• Proximity access control

Other

• Simple programming interface

• On-chip tunable RC oscillator, ± 10%

• On-chip EEPROM

• 64-bit user EEPROM in Transponder mode

• Battery-low LED indication

• Serialized Quick Turn Programming (SQTP^SM)

• 8-pin PDIP/SOIC

• RF Enable output

• ASK and FSK PLL interface option

• Built in LC input amplifier