HCS320_11 Datasheet, PDF (1/38 Pages) Microchip Technology – KEELOQ® Code Hopping Encoder Automatic code word completion

HCS320
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 function code, 2-bit status)
• Encryption keys are read protected
Operating
• 3.5V - 13.0V operation
• Shift key and three inputs
• 16 functions available
• Selectable baud rate
• Automatic code word completion
• Battery low signal transmitted to receiver
• Battery low indication on LED
• 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 HCS320 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 HCS320 from Microchip Technology Inc. is a code
hopping encoder designed for secure Remote Keyless
Entry (RKE) systems. The HCS320 utilizes the code
hopping technology which incorporates high security, a
small package outline, and low cost, to make this
device a perfect solution for unidirectional remote key-
less entry systems and access control systems.
PACKAGE TYPES
PDIP, SOIC
S0 1
S1 ²
S2 3
SHIFT 4
8 VDD
7 LED
6 PWM
5 ^VSS
HCS320 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
SHIFT S₂ S₁ S₀
The HCS320 combines a 32-bit hopping code gener-
ated by a nonlinear encryption algorithm, with a 28-bit
serial number and six status bits to create a 66-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 grab-
bing) schemes useless.
© 2011 Microchip Technology Inc.
DS41097D-page 1