HCS201 Datasheet, PDF (1/28 Pages) Microchip Technology – KEELOQ Code Hopping Encoder

HCS201
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
• 34-bit fixed code (28-bit serial number,
4-bit button code, 2-bit status)
• Encryption keys are read protected
Operating
• 3.5V-13V operation
(2.0V min. using the Step up feature)
• Three button inputs
• 7 functions available
• Selectable baud rate
• Automatic code word completion
• Battery low signal transmitted to receiver
• Non-volatile synchronization data
Other
• Simple programming interface
• On-chip EEPROM
• On-chip oscillator and timing components
• Button inputs have internal pull-down resistors
• Minimum component count
• Synchronous Transmission mode
• Built-in step up regulator
Typical Applications
• The HCS201 is ideal for Remote Keyless Entry
(RKE) applications. These applications include:
• Automotive RKE systems
• Automotive alarm systems
• Automotive immobilizers
• Gate and garage door openers
• Identity tokens
• Burglar alarm systems
DESCRIPTION
The HCS201 from Microchip Technology Inc. is a code
hopping encoder designed for secure Remote Keyless
Entry (RKE) systems. The HCS201 utilizes the KEELOQ
code hopping technology, incorporating high security, a
small package outline and low cost. The HCS201 is a
perfect solution for unidirectional remote keyless entry
systems and access control systems.
PACKAGE TYPES
PDIP, SOIC
S0 1
S1 2
S2 3
VDDB 4
8 VDD
7 STEP
6 DATA
5 ^VSS
HCS201 BLOCK DIAGRAM
VDDB
VDD
Step Up
Controller
Oscillator
RESET circuit
Controller
Power
latching
and
switching
STEP
EEPROM
Encoder
DATA
VSS
VDD
32-bit shift register
Button input port
S₂ S₁ S₀
The HCS201 combines a 32-bit hopping code,
generated by a nonlinear encryption algorithm, with a
28-bit serial number and 6 information bits to create a
66-bit code word. The code word length eliminates the
threat of code scanning and the code hopping mecha-
nism makes each transmission unique, thus rendering
code capture and resend schemes useless.
© 2001 Microchip Technology Inc.
DS41098C-page 1