HCS200 Datasheet, PDF (1/16 Pages) Microchip Technology – KEELOQ CODE HOPPING ENCODER

HCS200
KEELOQ^® Code Hopping Encoder*
FEATURES
Security
• Programmable 28-bit serial number
• Programmable 64-bit encryption key
• Each transmission is unique
• 66-bit transmission code length
• 32-bit hopping code
• 28-bit serial number, 4-bit function code,
VLOW indicator transmitted
• Encryption keys are read protected
Operating
• 3.5–13.0V operation
• Three button inputs
- seven functions available
• Selectable baud rate
• Automatic code word completion
• Battery low signal transmitted to receiver
• Non-volatile synchronization data
Other
• Easy to use programming interface
• On-chip EEPROM
• On-chip oscillator and timing components
• Button inputs have internal pulldown resistors
• Low external component cost
Typical Applications
The HCS200 is ideal for Remote Keyless Entry (RKE)
applications. These applications include:
• Fixed code replacement
• Automotive RKE systems
• Automotive alarm systems
• Automotive immobilizers
• Gate and garage door openers
• Identity tokens
• Burglar alarm systems
DESCRIPTION
The HCS200, from Microchip Technology Inc., is a code
hopping encoder designed for Remote Keyless Entry
(RKE) systems. The HCS200 utilizes the Keeloq® code
hopping technology, which incorporates high security, a
small package outline and low cost, to make this device
a perfect solution for replacement of fixed code devices
in unidirectional remote keyless entry systems and
access control systems.
KeeLoq is a trademark of Microchip Technology Inc.
*Code hopping encoder patents issued in Europe, U. S. A., and R. S. A.
PACKAGE TYPES
PDIP, SOIC
S0 1
S1 2
S2 3
NC 4
8 VDD
7 NC
6 PWM
5 ^VSS
BLOCK DIAGRAM
Oscillator
Reset circuit
Controller
Power
latching
and
switching
PWM
EEPROM
Encoder
32-bit shift register
Vss
Button input port
VDD
S2 S1 S0
The HCS200 combines a 32-bit hopping code
generated by a non-linear encryption algorithm, with a
28-bit serial number and 6 information bits to create a
66-bit transmission stream. The length of the
transmission eliminates the threat of code scanning,
and the code hopping mechanism makes each
transmission unique, thus rendering code capture and
resend schemes useless.
The encryption key, serial number, and configuration
data are stored in EEPROM which is not accessible via
any external connection. This makes the HCS200 a
very secure unit. The HCS200 provides an easy to use
serial interface for programming the necessary security
keys, system parameters, and configuration data.
All encryption keys and code combinations are pro-
grammable but read-protected. The keys can only be
verified after an automatic erase and programming
operation. This protects against attempts to gain
access to keys and manipulate synchronization values.
© 1996 Microchip Technology Inc.
Preliminary
DS40138A-page 1
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