Imagine walking up to your vehicle, arms full of grocery bags. Without digging for keys or pressing any buttons, the vehicle detects you 1,5 m away as the authorised operator. The car unlocks the doors automatically, the driver's door opens and the seat and rear-view mirror adjust to your favourite position. All of this can be accomplished with the low-cost HCS412 single-chip solution introduced today by Microchip Technology.
The HCS412 is a code hopping encoder and transponder designed for secure entry systems. The device uses the patented KEELOQ code hopping algorithm and 32-bit bidirectional challenge-and-response for logical and physical access control. The device incorporates a sensitive passive-entry amplifier that eliminates the need for more than 10 discrete components and a complex low-frequency design required in similar applications. The HCS412 enhances the performance of Microchip's KEELOQ family of eight encoder and three decoder solutions. KEELOQ is an industry standard for highly secure remote control and access control applications.
The encoder function of the HCS412 can remotely lock and unlock a car door, garage or estate gate using radio frequency. The device provides the necessary control signals to interface directly to popular FSK and ASK PLLs (phase lock loop). The passive entry function allows vehicle entry without activating the remote control or inserting the key. When the key is detected within 1,5 m, the vehicle automatically unlocks the doors. The passive entry feature uses low-frequency bidirectional communication to the keyfob and radio frequency to the vehicle. With only eight pins and small package size, the HCS412 easily fits in keyhead applications.
The HCS412 can also function as a batteryless transponder in back-up mode when the battery fails. In this mode, low frequency communication is used in both directions. An anticollision feature allows fast authentication in passive entry for multiple transponders in a field.
The HCS412 combines a 32-bit code hopping mechanism generated by a nonlinear encryption algorithm with a programmable 28-bit serial number to identify the transmitter and six status bits to create a 69-bit transmission stream. A programmable 64-bit encoder key and two 64-bit transponder keys are also utilised. The length of the transmission eliminates the threat of code scanning and the code hopping mechanism makes each transmission unique, rendering code capture and resend ('code grabbing') schemes systems useless. The device provides features typically required in higher-end security systems, including a longer transmission length of 69 bits and extended 60-bit read-protected seed for secure learning and CRC error detection.
The encoder key, serial number and configuration data are stored in EEPROM which is not accessible via any external connection, making the HCS412 a very secure device. The HCS412 provides a serial interface for programming the necessary security keys, system parameters and configurations data. The HCS412 has 2,0-6,6 operating voltage, on-chip tuneable oscillator and timing components, three switch inputs and nonvolatile synchronisation.
The KEELOQ code hopping technology incorporates high security, a small package outline and low cost to make this device a perfect solution for unidirectional and bidirectional RKE systems and access control systems. Typical applications for the HCS412 can include automotive remote entry systems, automotive alarm systems, automotive immobilisers, gate and garage door openers, electronic door locks (home/office/hotel), burglar alarm systems and proximity access control.
Available in 8-pin PDIP and SOIC packages, pricing for the HCS412 is $1,31 each in 1000-unit quantities. Samples are available today with volume production planned for third quarter 1999. The HCS412 will also be offered as a transponder in a leadless SOT385 package. The SOT385 will available in the fourth quarter of 1999.
For details contact Willem Hijbeek, Tempe Technology.
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