HCS473
Data Sheet
Code Hopping Encoder and Transponder
2002 Microchip Technology Inc.
Preliminary
DS40035C
Note the following details of the code protection feature on Microchip devices:
•
•
Microchip products meet the specification contained in their particular Microchip Data Sheet.
Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowl-
edge, require using the Microchip products in a manner outside the operating specifications contained in Microchip's Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
Microchip is willing to work with the customer who is concerned about the integrity of their code.
Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
•
•
•
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products.
Information contained in this publication regarding device
applications and the like is intended through suggestion only
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
No representation or warranty is given and no liability is
assumed by Microchip Technology Incorporated with respect
to the accuracy or use of such information, or infringement of
patents or other intellectual property rights arising from such
use or otherwise. Use of Microchip’s products as critical com-
ponents in life support systems is not authorized except with
express written approval by Microchip. No licenses are con-
veyed, implicitly or otherwise, under any intellectual property
rights.
Trademarks
The Microchip name and logo, the Microchip logo, K
EE
L
OQ
,
MPLAB, PIC, PICmicro, PICSTART and PRO MATE are
registered trademarks of Microchip Technology Incorporated
in the U.S.A. and other countries.
FilterLab, microID, MXDEV, MXLAB, PICMASTER, SEEVAL
and The Embedded Control Solutions Company are
registered trademarks of Microchip Technology Incorporated
in the U.S.A.
dsPIC, dsPICDEM.net, ECONOMONITOR, FanSense,
FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP,
ICEPIC, microPort, Migratable Memory, MPASM, MPLIB,
MPLINK, MPSIM, PICC, PICDEM, PICDEM.net, rfPIC, Select
Mode and Total Endurance are trademarks of Microchip
Technology Incorporated in the U.S.A. and other countries.
Serialized Quick Turn Programming (SQTP) is a service mark
of Microchip Technology Incorporated in the U.S.A.
All other trademarks mentioned herein are property of their
respective companies.
© 2002, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.
Printed on recycled paper.
Microchip received QS-9000 quality system
certification for its worldwide headquarters,
design and wafer fabrication facilities in
Chandler and Tempe, Arizona in July 1999
and Mountain View, California in March 2002.
The Company’s quality system processes and
procedures are QS-9000 compliant for its
PICmicro
®
8-bit MCUs, K
EE
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OQ
®
code hopping
devices, Serial EEPROMs, microperipherals,
non-volatile memory and analog products. In
addition, Microchip’s quality system for the
design and manufacture of development
systems is ISO 9001 certified.
DS40035C - page ii
Preliminary
2002 Microchip Technology Inc.
HCS473
K
EE
L
OQ®
3-Axis Transcoder
FEATURES
Encoder Security
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Read protected 64-bit encoder key
69-bit transmission length
60-bit, read protected seed for secure learning
Programmable 32-bit serial number
Non-volatile 16/20-bit synchronization counter
Package Types
PDIP, SOIC
S0
S1
S2
S3/RFEN
V
DDT
LCX
1
2
14
13
V
DD
LED
DATA
V
SS
V
SST
LCCOM
LCZ
HCS473
3
4
5
6
7
12
11
10
9
8
Encoder Operation
•
•
•
•
•
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2.05V to 5.5V operation
Four switch inputs – up to 15 functions codes
PWM or Manchester modulation
Selectable Baud Rate (416 - 5,000 bps)
Transmissions include button queuing information
PLL interface
LCY
Block Diagram
Low
Voltage
Detector
RESET and
Power
Control
V
DD
V
SS
Transponder Security
•
•
•
•
•
•
2 read protected 64-bit Challenge/Response keys
Two IFF encryption algorithms
16/32-bit Challenge/Response
Separate Vehicle ID and Token ID
2 vehicles supported
CRC on all communication
Internal
Oscillator
EEPROM
S0
S1
S2
S3/
RFEN
Wake-up
Control
Control
Logic
LED
Driver
LED
Data
Output
DATA
Transponder Operation
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•
•
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Three sensitive transponder inputs
Bi-directional transponder communication
Transponder in/RF out operation
Anticollision of multiple transponders
Intelligent damping for high Q-factor LC-circuits
Low battery operation
Passive proximity activation
64-bit secure user EEPROM
Fast reaction time
LCX
LCY
LCZ
3 Input Transponder
Circuitry
V
DDT
LCCOM
V
SST
Typical Applications
•
•
•
•
•
•
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Passive entry systems
Automotive remote entry systems
Automotive alarm systems
Automotive immobilizers
Gate and garage openers
Electronic door locks (Home/Office/Hotel)
Burglar alarm systems
Proximity access control
Passive proximity authentication
Peripherals
• Low Voltage Detector
• On-board RC oscillator with
±10%
variation
2002 Microchip Technology Inc.
Preliminary
DS40035C-page 1
HCS473
Table of Contents
1.0 General Description ..................................................................................................................................................................... 3
2.0 Device Description ...................................................................................................................................................................... 5
3.0 Device Operation ....................................................................................................................................................................... 11
4.0 Programming Specification ....................................................................................................................................................... 37
5.0 Integrating the HCS473 Into A System ..................................................................................................................................... 39
6.0 Development Support................................................................................................................................................................. 43
7.0 Electrical Characteristics ........................................................................................................................................................... 49
8.0 Packaging Information................................................................................................................................................................ 57
INDEX .................................................................................................................................................................................................. 61
On-Line Support................................................................................................................................................................................... 62
Systems Information and Upgrade Hot Line ........................................................................................................................................ 62
Reader Response ................................................................................................................................................................................ 63
Product Identification System............................................................................................................................................................... 64
TO OUR VALUED CUSTOMERS
It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip
products. To this end, we will continue to improve our publications to better suit your needs. Our publications will be refined and
enhanced as new volumes and updates are introduced.
If you have any questions or comments regarding this publication, please contact the Marketing Communications Department via
E-mail at
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or fax the
Reader Response Form
in the back of this data sheet to (480) 792-4150.
We welcome your feedback.
Most Current Data Sheet
To obtain the most up-to-date version of this data sheet, please register at our Worldwide Web site at:
http://www.microchip.com
You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page.
The last character of the literature number is the version number, (e.g., DS30000A is version A of document DS30000).
Errata
An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for current
devices. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the revision
of silicon and revision of document to which it applies.
To determine if an errata sheet exists for a particular device, please check with one of the following:
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DS40035C-page 2
Preliminary
2002 Microchip Technology Inc.
HCS473
1.0
GENERAL DESCRIPTION
The HCS473 combines the patented K
EE
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code
hopping technology and bi-directional transponder
challenge-and-response security into a single chip
solution for logical and physical access control.
The three-input transponder interface allows the com-
bination of three orthogonal transponder antennas,
eliminating the directionality associated with traditional
single antenna transponder systems.
When used as a code hopping encoder, the HCS473 is
well suited to keyless entry systems; vehicle and
garage door access in particular. The same HCS473
can also be used as a secure bi-directional transponder
for contactless authentication. These capabilities make
the HCS473 ideal for combined secure access control
and identification applications, dramatically reducing
the cost of hybrid transmitter/transponder solutions.
•
Encryption Algorithm
- A recipe whereby data is
scrambled using a crypto key. The data can only
be interpreted by the respective decryption algo-
rithm using the same crypto key.
•
IFF
- Identify Friend or Foe, a classic authentica-
tion method (Section 3.2.3.3).
•
Learn
- Learning involves the receiver calculating
the transmitter’s appropriate crypto key, decrypt-
ing the received hopping code and storing the
serial number, synchronization counter value and
crypto key in EEPROM (Section 5.1). The
K
EE
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OQ
product family facilitates several learning
strategies to be implemented on the decoder. The
following are examples of what can be done.
•
Simple Learning
The receiver uses a fixed crypto key, common to
all components of all systems by the same manu-
facturer, to decrypt the received code word’s
encrypted portion.
•
Normal Learning
The receiver uses information transmitted during
normal operation to derive the crypto key and
decrypt the received code word’s encrypted por-
tion.
•
Secure Learn
The transmitter is activated through a special but-
ton combination to transmit a stored 60-bit seed
value used to derive the transmitter’s crypto key.
The receiver uses this seed value to calculate the
same crypto key and decrypt the received code
word’s encrypted portion.
•
LF
- Low Frequency. For HCS473 purposes, LF
refers to a typical 125 kHz frequency.
•
Manufacturer’s code
– A unique and secret 64-
bit number used to generate unique encoder
crypto keys. Each encoder is programmed with a
crypto key that is a function of the manufacturer’s
code. Each decoder is programmed with the man-
ufacturer code itself.
•
Proximity Activation
- A method whereby an
encoder automatically initiates a transmission in
response to detecting an inductive field
(Section 3.1.1.2).
•
PKE
- Passive Keyless Entry.
•
RKE -
Remote Keyless Entry.
•
Transmission
- A data stream consisting of
repeating code words.
•
Transcoder
- Device combining unidirectional
transmitter capabilities with bi-directional authenti-
cation capabilities.
•
Transponder
- A transmitter-receiver activated
for transmission by reception of a predetermined
signal.
1.1
1.1.1
System Overview
KEY TERMS
The following is a list of key terms used throughout this
data sheet. For additional information on terminology,
please refer to the K
EE
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introductory Technical Brief
(TB003).
•
AGC
- Automatic Gain Control.
•
Anticollision
- A scheme whereby transponders
in the same field can be addressed individually,
preventing simultaneous response to a command
(Section 3.2.1.4).
•
Button Status
- Indicates what button input(s)
activated the transmission. Encompasses the 4
button status bits S3, S2, S1 and S0 (Figure 3-2).
•
Code Hopping
- A method by which a code,
viewed externally to the system, appears to
change unpredictably each time it is transmitted
(Section 1.2.3).
•
Code word
- A block of data that is repeatedly
transmitted upon button activation (Figure 3-2).
•
Crypto key
- A unique and secret 64-bit number
used to encrypt and decrypt data. In a symmetri-
cal block cipher such as the K
EE
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algorithm,
the encryption and decryption keys are equal and
will therefore be referred to generally as the
crypto key.
•
Decoder
- A device that decodes data received
from an encoder.
•
Decryption algorithm
- A recipe whereby data
scrambled by an encryption algorithm can be
unscrambled using the same crypto key.
•
Device Identifier
- 16-bit value used to uniquely
select one of multiple transponders for communi-
cation.
•
Encoder
- A device that generates and encodes
data.
2002 Microchip Technology Inc.
Preliminary
DS40035C-page 3
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