HCS301
K
EE
L
OQ
®
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
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DESCRIPTION
The HCS301 from Microchip Technology Inc. is a code
hopping encoder designed for secure Remote Keyless
Entry (RKE) systems. The HCS301 utilizes the K
EE
L
OQ
code hopping technology, which incorporates high
security, a small package outline and low cost, to make
this device a perfect solution for unidirectional remote
keyless entry systems and access control systems.
PACKAGE TYPES
PDIP, SOIC
S0
S1
S2
S3
1
HCS301
2
3
4
8
7
6
5
V
DD
Operating
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•
•
•
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3.5V - 13.0V operation
Four button inputs
No additional circuitry required
15 functions available
Selectable baud rate
Automatic code word completion
Battery low signal transmitted to receiver
Battery low indication on LED
Non-volatile synchronization data
LED
PWM
V
SS
HCS301 BLOCK DIAGRAM
Oscillator
RESET circuit
LED
LED driver
Controller
Power
latching
and
switching
Other
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•
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•
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•
Functionally identical to HCS300
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
EEPROM
Encoder
PWM
32-bit shift register
V
SS
V
DD
Button input port
Typical Applications
The HCS301 is ideal for Remote Keyless Entry (RKE)
applications. These applications include:
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Automotive RKE systems
Automotive alarm systems
Automotive immobilizers
Gate and garage door openers
Identity tokens
Burglar alarm systems
S3 S2
S1
S0
The HCS301 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.
DS21143B-page 1
MICROCHIP [ MICROCHIP TECHNOLOGY ]
