HCS300_01 Datasheet, PDF (1/28 Pages) Microchip Technology – KEE LOQ Code Hopping Encoder

HCS300
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 button code, 2-bit status
• Crypt keys are read protected
Operating
• 2.0V - 6.3V operation
• Four button inputs
• No additional circuitry required
• 15 functions available
• Selectable baud rate
• Automatic code word completion
• Low battery 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 pull-down resistors
• Current limiting on LED output
• Low external component cost
Typical Applications
The HCS300 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 HCS300 from Microchip Technology Inc. is a code
hopping encoder designed for secure Remote Keyless
Entry (RKE) systems. The HCS300 utilizes the KEELOQ
code hopping technology, incorporating high security, a
small package outline and low cost. The HCS300 is a
perfect solution for unidirectional remote keyless entry
systems and access control systems.
PACKAGE TYPES
PDIP, SOIC
S0 1
S1 2
S2 3
S3 4
8 VDD
7 LED
6 PWM
5 ^VSS
HCS300 BLOCK DIAGRAM
Oscillator
RESET circuit
LED
LED driver
Controller
Power
latching
and
switching
PWM
EEPROM
Encoder
32-bit shift register
VSS
VDD
Button input port
S3 S2 S1 S0
The HCS300 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.
DS21137F-page 1