M
HCS361
Code Hopping Encoder*
FEATURES
PACKAGE TYPES
PDIP, SOIC
Security
8
7
6
5
VDD
LED
PWM
VSS
S0
1
2
3
4
• 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
S1
S2
S3
Operating
HCS361 BLOCK DIAGRAM
• 2.0-6.6V operation
• Four button inputs
- 15 functions available
Oscillator
Power
latching
and
Controller
Reset circuit
switching
• Selectable baud rate
LED
LED driver
• Automatic code word completion
• Battery low signal transmitted to receiver
• Nonvolatile synchronization data
• PWM and VPWM modulation
EEPROM
Encoder
Other
PWM
• Easy to use programming interface
• On-chip EEPROM
32-bit shift register
• On-chip oscillator and timing components
• Button inputs have internal pulldown resistors
• Current limiting on LED output
• Minimum component count
VSS
Button input port
VDD
Enhanced Features Over HCS300
S2
S3
S1 S0
• 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
DESCRIPTION
The HCS361 is a code hopping encoder designed for
secure Remote Keyless Entry (RKE) systems. The
HCS361 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 unidirectional remote keyless entry systems
and access control systems.
Typical Applications
The HCS361 is ideal for Remote Keyless Entry (RKE)
applications. These applications include:
The HCS361 combines
a 32-bit hopping code
• Automotive RKE systems
• Automotive alarm systems
• Automotive immobilizers
• Gate and garage door openers
• Identity tokens
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.
• Burglar alarm systems
KEELOQ is a trademark of Microchip Technology Inc.
*Code hopping encoder patents issued in Europe, U. S. A., R. S. A. — US: 5,517,187; Europe: 0459781
1996 Microchip Technology Inc.
Preliminary
DS40146C-page 1