
1996 Microchip Technology Inc.
Preliminary
DS40146C-page 1
M
FEATURES
Security
Programmable 28/32-bit serial number
Programmable 64-bit encryption key
Each transmission is unique
67-bit transmission code length
32-bit hopping code
35-bit fixed code (28/32-bit serial number,
4/0-bit function code, 1-bit status, 2-bit CRC)
Encryption keys are read protected
Operating
2.0-6.6V operation
Four button inputs
- 15 functions available
Selectable baud rate
Automatic code word completion
Battery low signal transmitted to receiver
Nonvolatile synchronization data
PWM and VPWM modulation
Other
Easy to use programming interface
On-chip EEPROM
On-chip oscillator and timing components
Button inputs have internal pulldown resistors
Current limiting on LED output
Minimum component count
Enhanced Features Over HCS300
48-bit seed vs. 32-bit seed
2-bit CRC for error detection
28/32-bit serial number select
Two seed transmission methods
PWM and VPWM modulation
Wake-up signal in VPWM mode
IR modulation mode
Typical Applications
The HCS361 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
PACKAGE TYPES
HCS361 BLOCK DIAGRAM
DESCRIPTION
The HCS361 is a code hopping encoder designed for
secure Remote Keyless Entry (RKE) systems. The
HCS361 utilizes the K
EE
L
OQ
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.
The HCS361 combines a 32-bit hopping code
generated by a nonlinear encryption algorithm, with a
28/32-bit serial number and 7/3 status bits to create a
67-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 (code grabbing) schemes useless.
code hopping technology,
1
2
3
4
8
7
6
5
S0
S1
S2
S3
V
DD
LED
PWM
V
SS
PDIP, SOIC
H
V
SS
V
DD
Oscillator
Reset circuit
LED driver
Controller
Power
latching
and
switching
Button input port
32-bit shift register
Encoder
EEPROM
PWM
LED
S
3
S
2
S
1
S
0
K
*Code hopping encoder patents issued in Europe, U. S. A., R. S. A. — US: 5,517,187; Europe: 0459781
L
is a trademark of Microchip Technology Inc.
HCS361
Code Hopping Encoder*