900,000+ datasheet pdf search and download

Datasheet4U offers most rated semiconductors data sheet pdf




  Microchip Technology Semiconductor Electronic Components Datasheet  

HCS300 Datasheet

KEE LOQ Code Hopping Encoder

No Preview Available !

HCS300
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
Operating
• 2.0—6.3V operation
• Four button inputs
- No additional circuitry required
- 15 functions available
• Selectable baud rate
• Automatic code word completion
• Battery low 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 pulldown resistors
• Current limiting on LED output
• Minimum component count
• Synchronous transmission mode
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, which incorporates high secu-
rity, 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.
KeeLoq is a trademark of Microchip Technology Inc.
*Code hopping encoder patents allowed and pending.
PACKAGE TYPES
PDIP, SOIC
S0 1
S1 2
S2 3
S3 4
8 VDD
7 LED
6 PWM
5 VSS
HCS300 BLOCK DIAGRAM
Oscillator
LED
Reset circuit
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 non-linear 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 grabbing) schemes useless.
The encryption key, serial number, and configuration
data are stored in EEPROM which is not accessible via
any external connection. This makes the HCS300 a
very secure unit. The HCS300 provides an easy to use
serial interface for programming the necessary security
keys, system parameters, and configuration data.
The encyrption keys and code combinations are pro-
grammable but read-protected. The keys can only be
verified after an automatic erase and programming
operation. This protects against attempts to gain
access to keys and manipulate synchronization values.
© 1996 Microchip Technology Inc.
Preliminary
DS21137D-page 1
This document was created with FrameMaker 4 0 4


  Microchip Technology Semiconductor Electronic Components Datasheet  

HCS300 Datasheet

KEE LOQ Code Hopping Encoder

No Preview Available !

HCS300
The HCS300 operates over a wide voltage range of
2.0V to 6.3V and has four button inputs in an 8-pin
configuration. This allows the system designer the
freedom to utilize up to 15 functions. The only
components required for device operation are the but-
tons and RF circuitry, allowing a very low system cost.
1.0 SYSTEM OVERVIEW
Key Terms
• Manufacturer’s code - a 64-bit word, unique to
each manufacturer, used to produce a unique
encryption key in each transmitter (encoder).
• Encryption Key - a unique 64-bit key generated
and programmed into the encoder during the
manufacturing process. The encryption key
controls the encryption algorithm and is stored in
EEPROM on the encoder device.
1.1 Learn
The HCS product family facilitates several learn strate-
gies to be implemented on the decoder. The following
are examples of what can be done. It must be pointed
out that their exists some third-party patents on learn-
ing strategies and implementation.
1.1.1 NORMAL LEARN
The receiver uses the same information that is transmit-
ted during normal operation to derive the transmitter’s
secret key, decrypt the discrimination value and the
synchronization counter.
1.1.2 SECURE LEARN*
The transmitter is activated through a special button
combination to transmit a stored 48-bit value (random
seed) that can be used for key generation or be part of
the key. Transmission of the random seed can be dis-
abled after learning is completed.
The HCS300 is a code hopping encoder device that is
designed specifically for keyless entry systems,
primarily for vehicles and home garage door openers. It
is meant to be a cost-effective, yet secure solution to
such systems. The encoder portion of a keyless entry
system is meant to be held by the user and operated to
gain access to a vehicle or restricted area. The
HCS300 requires very few external components
(Figure 2-1).
Most keyless entry systems transmit the same code
from a transmitter every time a button is pushed. The
relative number of code combinations for a low end sys-
tem is also a relatively small number. These
shortcomings provide the means for a sophisticated
thief to create a device that ‘grabs’ a transmission and
re-transmits it later or a device that scans all possible
combinations until the correct one is found.
The HCS300 employs the KEELOQ code hopping tech-
nology and an encryption algorithm to achieve a high
level of security. Code hopping is a method by which
the code transmitted from the transmitter to the receiver
is different every time a button is pushed. This method,
coupled with a transmission length of 66 bits, virtually
eliminates the use of code ‘grabbing’ or code
‘scanning’.
As indicated in the block diagram on page one, the
HCS300 has a small EEPROM array which must be
loaded with several parameters before use. The most
important of these values are:
• A 28-bit serial number which is meant to be
unique for every encoder
• An encryption key that is generated at the time of
production
• A 16-bit synchronization value
The serial number for each transmitter is programmed
by the manufacturer at the time of production. The
generation of the encryption key is done using a key
generation algorithm (Figure 1-1). Typically, inputs to
the key generation algorithm are the serial number of
the transmitter and a 64-bit manufacturer’s code. The
manufacturer’s code is chosen by the system
manufacturer and must be carefully controlled. The
manufacturer’s code is a pivotal part of the overall
system security.
FIGURE 1-1: CREATION AND STORAGE OF ENCRYPTION KEY DURING PRODUCTION
Transmitter
Serial Number or
Seed
Manufacturer’s
Code
Key
Generation
Algorithm
Encryption
Key
HCS300 EEPROM Array
Serial Number
Encryption Key
Sync Counter
.
.
.
DS21137D-page 2
Preliminary
© 1996 Microchip Technology Inc.


Part Number HCS300
Description KEE LOQ Code Hopping Encoder
Maker Microchip Technology
PDF Download

HCS300 Datasheet PDF






Similar Datasheet

1 HCS300 KEE LOQ Code Hopping Encoder
Microchip Technology
2 HCS301 KEELOQ CODE HOPPING ENCODER
Microchip Technology





Part Number Start With

0    1    2    3    4    5    6    7    8    9    A    B    C    D    E    F    G    H    I    J    K    L    M    N    O    P    Q    R    S    T    U    V    W    X    Y    Z



Site map

Webmaste! click here

Contact us

Buy Components

Privacy Policy