Microchip HCS360-IP Keeloq code hopping encoder Datasheet

M
HCS360
Code Hopping Encoder
FEATURES
PACKAGE TYPES
PDIP, SOIC
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
S0
1
S1
2
S2
3
S3
4
8
VDD
7
LED
6
PWM
5
VSS
HCS360
•
•
•
•
•
•
HCS360 BLOCK DIAGRAM
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 Manchester modulation
Oscillator
Power
latching
and
switching
Controller
Reset circuit
LED
LED driver
EEPROM
Encoder
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
Minimum component count
PWM
32-bit shift register
VSS
Button input port
VDD
Enhanced Features Over HCS300
•
•
•
•
•
•
S3 S2
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 Manchester modulation
IR modulation mode
DESCRIPTION
Typical Applications
The HCS360 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
S1 S0
The HCS360 is a code hopping encoder designed for
secure Remote Keyless Entry (RKE) systems. The
HCS360 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.
The HCS360 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.
KEELOQ is a registered 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
DS40152C-page 1
HCS360
The encryption key, serial number, and configuration
data are stored in EEPROM which is not accessible via
any external connection. This makes the HCS360 a
very secure unit. The HCS360 provides an easy to use
serial interface for programming the necessary security
keys, system parameters, and configuration data.
The encryption keys and code combinations are programmable 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.
The HCS360 operates over a wide voltage range of
2.0V to 6.6V 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 buttons and RF circuitry, allowing a very low system cost.
1.0
SYSTEM OVERVIEW
1.1
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.
• Learn – The HCS product family facilitates several
learning strategies to be implemented on the
decoder. The following are examples of what can
be done.
Normal Learning
The receiver uses the same information that is
transmitted during normal operation to derive the
transmitter’s secret key, decrypt the discrimination
value and the synchronization counter.
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 disabled after learning is
completed.
The HCS360 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
HCS360 requires very few external components
(Figure 2-1).
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
retransmits it later or a device that scans all possible
combinations until the correct one is found.
The HCS360 employs the KEELOQ code hopping technology 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 67 bits, virtually
eliminates the use of code ‘grabbing’ or code
‘scanning’.
As indicated in the block diagram on page one, the
HCS360 has a small EEPROM array which must be
loaded with several parameters before use. The most
important of these values are:
• A 28/32-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 or seed value, 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.
The 16-bit synchronization value is the basis for the
transmitted code changing for each transmission, and
is updated each time a button is pressed. Because of
the complexity of the code hopping encryption algorithm, a change in one bit of the synchronization value
will result in a large change in the actual transmitted
code. There is a relationship (Figure 1-2) between the
key values in EEPROM and how they are used in the
encoder. Once the encoder detects that a button has
been pressed, the encoder reads the button and
updates the synchronization counter. The synchronization value is then combined with the encryption key in
the encryption algorithm and the output is 32 bits of
encrypted information. This data will change with every
button press, hence, it is referred to as the hopping
portion of the code word. The 32-bit hopping code is
combined with the button information and the serial
number to form the code word transmitted to the
receiver. The code word format is explained in detail
in Section 4.2.
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*Secure Learning patents pending.
DS40152C-page 2
Preliminary
 1996 Microchip Technology Inc.
HCS360
transmitter, the current synchronization value for that
transmitter and the same encryption key that is used on
the transmitter. If a receiver receives a message of valid
format, the serial number is checked and, if it is from a
learned transmitter, the message is decrypted and the
decrypted synchronization counter is checked against
what is stored. If the synchronization value is verified,
then the button status is checked to see what operation
is needed. Figure 1-3 shows the relationship between
some of the values stored by the receiver and the values received from the transmitter.
Any type of controller may be used as a receiver, but it
is typically a microcontroller with compatible firmware
that allows the receiver to operate in conjunction with a
transmitter, based on the HCS360. Section 7.0
provides more detail on integrating the HCS360 into a
total system.
Before a transmitter can be used with a particular
receiver, the transmitter must be ‘learned’ by the
receiver. Upon learning a transmitter, information is
stored by the receiver so that it may track the
transmitter, including the serial number of the
FIGURE 1-1:
CREATION AND STORAGE OF ENCRYPTION KEY DURING PRODUCTION
HCS360 EEPROM Array
Transmitter
Serial Number or
Seed
Key
Generation
Algorithm
Manufacturer’s
Code
FIGURE 1-2:
Serial Number
Encryption Key
Sync Counter
.
.
.
Encryption
Key
BASIC OPERATION OF TRANSMITTER (ENCODER)
Transmitted Information
KEELOQ
Encryption
Algorithm
EEPROM Array
32 Bits of
Encrypted Data
Serial Number
Button Press
Information
Decryption Key
Sync Counter
Serial Number
FIGURE 1-3:
BASIC OPERATION OF RECEIVER (DECODER)
Check for
Match
EEPROM Array
KEELOQ
Decryption
Algorithm
Decryption Key
Decrypted
Synchronization
Counter
Sync Counter
Serial Number
Check for
Match
Manufacturer Code
Button Press
Information
Serial Number
32 Bits of
Encrypted Data
Received Information
 1996 Microchip Technology Inc.
Preliminary
DS40152C-page 3
HCS360
2.0
DEVICE OPERATION
As shown in the typical application circuits (Figure 2-1),
the HCS360 is a simple device to use. It requires only
the addition of buttons and RF circuitry for use as the
transmitter in your security application. A description of
each pin is described in Table 2-1.
FIGURE 2-1:
TYPICAL CIRCUITS
VDD
B0
S0
B1
S1
LED
S2
PWM
S3
VSS
VDD
Tx out
2 button remote control
VDD
B4 B3 B2 B1 B0
S0
VDD
S1
LED
S2
PWM
S3
VSS
The high security level of the HCS360 is based on the
patented KEELOQ technology. A block cipher type of
encryption algorithm based on a block length of 32 bits
and a key length of 64 bits is used. The algorithm
obscures the information in such a way that even if the
transmission information (before coding) differs by only
one bit from the information in the previous transmission, the next coded transmission will be totally different. Statistically, if only one bit in the 32-bit string of
information changes, approximately 50 percent of the
coded transmission will change. The HCS360 will wake
up upon detecting a switch closure and then delay
approximately 6.5 ms for switch debounce (Figure 2-2).
The synchronization information, fixed information, and
switch information will be encrypted to form the hopping
code. The encrypted or hopping code portion of the
transmission will change every time a button is
pressed, even if the same button is pushed again.
Keeping a button pressed for a long time will result in
the same code word being transmitted until the button
is released or time-out occurs. A code that has been
transmitted will not occur again for more than 64K
transmissions. This will provide more than 18 years of
typical use before a code is repeated based on 10 operations per day. Overflow information programmed into
the encoder can be used by the decoder to extend the
number of unique transmissions to more than 128K.
If, in the transmit process, it is detected that a new button(s) has been pressed, a reset will immediately be
forced and the code word will not be completed. Please
note that buttons removed will not have any effect on
the code word unless no buttons remain pressed in
which case the current code word will be completed
and the power down will occur.
Tx out
5 button remote control (Note)
Note: Up to 15 functions can be implemented by
pressing more than one button simultaneously or by using a suitable diode array.
TABLE 2-1
PIN DESCRIPTIONS
Name
Pin
Number
S0
1
Switch input 0
S1
2
Switch input 1
S2
3
Switch input 2/Can also be clock
pin when in programming mode
S3
4
Switch input 3/Clock pin when in
programming mode
VSS
5
Ground reference connection
PWM
6
Pulse width modulation (PWM)
output pin/Data pin for
programming mode
LED
7
Cathode connection for directly
driving LED during transmission
VDD
8
Positive supply voltage
connection
DS40152C-page 4
Description
Preliminary
 1996 Microchip Technology Inc.
HCS360
FIGURE 2-2:
ENCODER OPERATION
3.0
EEPROM MEMORY
ORGANIZATION
Power Up
(A button has been pressed)
Reset and Debounce Delay
(6.5 ms)
Sample Inputs
The HCS360 contains 192 bits (12 x 16-bit words) of
EEPROM memory (Table 3-1). This EEPROM array is
used to store the encryption key information,
synchronization value, etc. Further descriptions of the
memory array is given in the following sections.
TABLE 3-1
Update Sync Info
Encrypt With
Encryption Key
WORD
ADDRESS
MNEMONIC
0
KEY_0
1
Load Transmit Register
2
Transmit
3
Yes
Buttons
Added
?
No
All
Buttons
Released
?
Yes
EEPROM MEMORY MAP
4
5
No
6
7
8
7
Complete Code
Word Transmission
10
Stop
11
3.1
DESCRIPTION
64-bit encryption
key (word 0)
KEY_1
64-bit encryption
key (word 1)
KEY_2
64-bit encryption
key (word 2)
KEY_3
64-bit encryption
key (word 3)
SYNC_A
16-bit synchronization value
SYNC_B/SEED_2 16-bit synchronization or seed value
(word 2)
RESERVED
Set to 0000H
SEED_0
Seed Value (word 0)
SEED_1
Seed Value (word 1)
SER_0
Device Serial
Number (word 0)
SER_1
Device Serial
Number (word 1)
CONFIG
Configuration Word
Key_0 - Key_3 (64-Bit Encryption Key)
The 64-bit encryption key is used by the transmitter to
create the encrypted message transmitted to the
receiver. This key is created and programmed at the
time of production using a key generation algorithm.
Inputs to the key generation algorithm are the serial
number for the particular transmitter being used and a
secret manufacturer’s code. While the key generation
algorithm supplied from Microchip is the typical method
used, a user may elect to create their own method of
key generation. This may be done providing that the
decoder is programmed with the same means of creating the key for decryption purposes. If a seed is used,
the seed will also form part of the input to the key generation algorithm.
 1996 Microchip Technology Inc.
Preliminary
DS40152C-page 5
HCS360
3.2
SYNC_A, SYNC_B
(Synchronization Counter)
TABLE 3-2
CONFIGURATION WORD
Bit Number Symbol
This is the 16-bit synchronization value that is used to
create the hopping code for transmission. This value
will be changed after every transmission. A second synchronization value can be used to stay synchronized
with a second receiver.
3.3
SEED_0, SEED_1, and SEED_2
(Seed Word)
This is the three word (48 bits) seed code that will be
transmitted when seed transmission is selected. This
allows the system designer to implement the secure learn
feature or use this fixed code word as part of a different
key generation/tracking process or purely as a fixed code
transmission.
3.4
SER_0, SER_1
(Encoder Serial Number)
SER_0 and SER_1 are the lower and upper words of
the device serial number, respectively. There are 32 bits
allocated for the serial number and a selectable configuration bit determines whether 32 or 28 bits will be
transmitted. The serial number is meant to be unique
for every transmitter.
3.5
3.5.1
CONFIG
(Configuration Word)
The configuration word is a 16-bit word stored in
EEPROM array that is used by the device to store
information used during the encryption process, as well
as the status of option configurations. Further
explanations of each of the bits are described in the
following sections.
0
LNGRD
Long Guard Time
1
FAST 0
Baud Rate Selection
2
FAST 1
Baud Rate Selection
3
NU
Not Used
4
SEED
Seed Transmission enable
5
DELM
Delay mode enable
6
TIMO
Time out enable
7
IND
Independent mode enable
8
USRA0
User bit
9
USRA1
User bit
10
USRB0
User bit
11
USRB1
User bit
12
XSER
Extended serial number
enable
13
TMPSD
Temporary seed transmission enable
14
MANCH Manchester/PWM modulation selection
15
OVR
Overflow bit
LNGRD: LONG GUARD TIME
LNGRD = 1 selects the encoder to extend the guard
time between code words. This can be used to reduce
the average power transmitted over a 100ms window
and thereby transmit a higher peak power.
3.5.2
FAST 1, FAST 0 BAUD RATE SELECTION
FAST 1 and FAST 0 selects the baud rate according to
Table 3-3.
TABLE 3-3
DS40152C-page 6
Bit Description
Preliminary
BAUD RATE SELECTION
TE
FAST 1
FAST 0
400
200
200
100
0
0
1
1
0
1
0
1
 1996 Microchip Technology Inc.
HCS360
3.5.3
SEED: ENABLE SEED TRANSMISSION
If SEED = 0, seed transmission is disabled. The independent counter mode can only be used with seed
transmission disabled since SEED_2 is shared with the
second synchronization counter.
With SEED = 1, seed transmission is enabled. The
appropriate button code(s) must be activated to transmit the seed information. In this mode, the seed infor-
FIGURE 3-1:
mation (SEED_0, SEED_1, and SEED_2) and the
upper 12- or 16-bits of the serial number (SER_1) are
transmitted instead of the hop code.
Seed transmission is available for function codes
(Table 3-7) S[3:0] = 1001 and S[3:0] = 0011(delayed).
This takes place regardless of the setting of the IND bit.
The two seed transmissions are shown in Figure 3-1.
SEED TRANSMISSION
All examples shown with XSER = 1, SEED = 1
When S[3:0] = 1001, delay is not acceptable.
CRC+VLOW
SER_1
SEED_2
SEED_1
SEED_0
Data transmission direction
For S[3:0] = 0x3 before delay:
16-bit Data Word
16-bit Counter
Encrypt
CRC+VLOW
SER_1
SER_0
Encrypted Data
Data transmission direction
For S[3:0] = 0011 after delay (Note 1, Note 2):
CRC+VLOW
SER_1
SEED_2
SEED_1
SEED_0
Data transmission direction
Note 1: For Seed Transmission, SEED_2 is transmitted instead of SER_0.
2: For Seed Transmission, the setting of DELM has no effect.
 1996 Microchip Technology Inc.
Preliminary
DS40152C-page 7
HCS360
3.5.4
DELM: DELAY MODE
3.5.5
If DELM = 1, delay transmission is enabled. A delayed
transmission is indicated by inverting the lower nibble of
the discrimination value. The delay mode is primarily for
compatibility with previous KEELOQ devices. If
DELM = 0, delay transmission is disabled (Table 3-4).
TABLE 3-4
TIMO: TIME-OUT
If TIMO = 1, the time-out is enabled. Time-out can be
used to terminate accidental continuous transmissions.
When time-out occurs, the PWM output is set low and
the LED is turned off. Current consumption will be
higher than in standby mode since current will flow
through the activated input resistors. This state can be
exited only after all inputs are taken low. TIMO = 0, will
enable continuous transmission (Table 3-5).
TYPICAL DELAY TIMES
FAST1
FAST0
Number of Code
Words before Delay
Mode
Time Before Delay Mode
(MANCH = 0)
Time Ref Delay Mode
(MANCH = 1)
0
0
28
≈ 2.9s
≈ 5.1s
0
1
56
≈ 3.1s
≈ 6.4s
1
0
28
≈ 1.5s
≈ 3.2s
1
1
56
≈ 1.7s
≈ 4.5s
TABLE 3-5
TYPICAL TIME-OUT TIMES
FAST 1
FAST 0
Maximum Number of
Code Words Transmitted
Time Before Time-out
(MANCH = 0)
Time Before Time-out
(MANCH = 1)
0
0
256
≈ 26.5s
≈ 46.9
0
1
512
≈ 28.2s
≈ 58.4
1
0
256
≈ 14.1s
≈ 29.2
1
1
512
≈ 15.7s
≈ 40.7
DS40152C-page 8
Preliminary
 1996 Microchip Technology Inc.
HCS360
3.5.6
3.5.9
IND: INDEPENDENT MODE
The independent mode can be used where one
encoder is used to control two receivers. Two counters
(SYNC_A and SYNC_B) are used in independent
mode. As indicated in Table 3-7, function codes 1 to 7
use SYNC_A and 8 to 15 SYNC_B. The independent
mode also selects IR mode. In IR mode function codes
12 to 15 will use SYNC_B. The PWM output signal is
modulated with a 40 kHz carrier. It must be pointed out
the 40 kHz is derived from the internal clock and will
therefore vary with the same percentage as the baud
rate. If IND = 0, SYNC_A is used for all function codes.
If IND = 1, independent mode is enabled and counters
for functions are used according to Table 3-7.
The temporary seed transmission can be used to disable learning after the transmitter has been used for a
programmable number of operations. This feature can
be used to implement very secure systems. After learning is disabled, the seed information cannot be
accessed even if physical access to the transmitter is
possible. If TMPSD = 1 the seed transmission will be
disabled after a number of code hopping transmissions.
The number of transmissions before seed transmission
is disabled, can be programmed by setting the synchronization counter (SYNC_A, SYNC_B) to a value as
shown in Table .
For IND = 1 and S[3:0] ≡ 0xC, 0xD, 0xE, 0xF, Basic
Pulse Width modulation becomes:
3.5.7
TABLE 3-6
USRA,B: USER BITS
User bits form part of the discrimination value. The user
bits together with the IND bit can be used to identify the
counter that is used in independent mode.
3.5.8
TMPSD: TEMPORARY SEED
TRANSMISSION
Synchronous Counter
Values
Number of
Transmissions
0000H
128
0060H
64
0050H
32
0048H
16
XSER: EXTENDED SERIAL NUMBER
If XSER = 1, the full 32-bit serial number [SER_1,
SER_0] is transmitted. If XSER = 0, the four most significant bits of the serial number are substituted by
S[3:0] and is compatible with the HCS200/300/301.
TABLE 3-7
SYNCHRONOUS COUNTER
INITIALIZATION VALUES
FUNCTION CODES
S3
S2
S1
S0
IND = 0
IND = 1
Comments
Counter
1
0
0
0
1
A
A
2
0
0
1
0
A
A
3
0
0
1
1
A
A
4
0
1
0
0
A
A
5
0
1
0
1
A
A
6
0
1
1
0
A
A
7
0
1
1
1
A
A
8
1
0
0
0
A
B
9
1
0
0
1
A
B
10
1
0
1
0
A
B
11
1
0
1
1
A
B
12
1
1
0
0
A
B IR mode
13
1
1
0
1
A
B IR mode
14
1
1
1
0
A
B IR mode
15
1
1
1
1
A
B IR mode
 1996 Microchip Technology Inc.
Preliminary
If SEED = 1, transmit seed after delay.
If SEED = 1, transmit seed immediately.
DS40152C-page 9
HCS360
3.5.10
MANCH: MANCHESTER CODE
MODULATION
MANCH selects between Manchester code modulation
and PWM modulation. If MANCH = 1, Manchester code
modulation is selected:
If MANCH = 0, PWM modulation is selected.
3.5.11
OVR: OVERFLOW
The overflow bit is used to extend the number of possible synchronization values. The synchronization
counter is 16 bits in length, yielding 65,536 values
before the cycle repeats. Under typical use of
10 operations a day, this will provide nearly 18 years of
use before a repeated value will be used. Should the
system designer conclude that is not adequate, then
the overflow bit can be utilized to extend the number of
unique values. This can be done by programming OVR
to 1 at the time of production. The encoder will automatically clear OVR the first time that the transmitted synchronization value wraps from 0xFFFF to 0x0000.
Once cleared, OVR cannot be set again, thereby creating a permanent record of the counter overflow. This
prevents fast cycling of 64K counter. If the decoder system is programmed to track the overflow bits, then the
effective number of unique synchronization values can
be extended to 128K. If programmed to zero, the system will be compatible with the NTQ104/5/6 devices
(i.e., no overflow with discrimination bits set to zero).
4.0
TRANSMITTED WORD
4.1
Transmission Format (PWM)
The HCS360 transmission is made up of several parts
(Figure 4-1 and Figure 4-2). Each transmission is
begun with a preamble and a header, followed by the
encrypted and then the fixed data. The actual data is
67 bits which consists of 32 bits of encrypted data and
35 bits of fixed data. Each transmission is followed by
a guard period before another transmission can begin.
Refer to Table 8-4 and Table 8-5 for transmission timing
specifications. The encrypted portion provides up to
four billion changing code combinations and includes
the function bits (based on which buttons were activated) along with the synchronization counter value
and discrimination value. The non-encrypted portion is
comprised of the CRC bits, VLOW bits, the function bits
and the 28/32-bit serial number. The encrypted and
non-encrypted sections combined increase the number
of combinations to 1.47 x 10 20.
4.2
Code Word Organization
The HCS360 transmits a 67-bit code word when a button is pressed. The 67-bit word is constructed from a
Fixed Code portion and an Encrypted Code portion
(Figure 4-3).
The Encrypted Data is generated from 4 function bits,
2 user bits, overflow bit, independent mode bit, and 8
serial number bits, and the 16-bit synchronization value
(Figure 8-4).
The Non-encrypted Code Data is made up of a VLOW
bit, 2 CRC bits, 4 function bits, and the 28-bit serial
number. If the extended serial number (32 bits) is
selected, the 4 function code bits will not be transmitted.
DS40152C-page 10
Preliminary
 1996 Microchip Technology Inc.
HCS360
FIGURE 4-1:
TRANSMISSION FORMAT—MANCH = 0
TOTAL TRANSMISSION:
1 CODE WORD
Preamble Sync Encrypt Fixed
Guard
Preamble Sync
Encrypt
CODE WORD:
TE
LOGIC "0"
LOGIC "1"
BIT
TE
1 2
4 5
16
6
13 14 15
1 3 5 7 9
2 4 6 8 10
Encrypted
TX Data
Sync
Preamble
Guard
Time
Fixed Code
Data
Code Word
FIGURE 4-2:
TRANSMISSION FORMAT—MANCH = 1
TOTAL TRANSMISSION:
1 CODE WORD
Preamble
Sync
Encrypt
Fixed
Guard
Preamble
Sync
Encrypt
CODE WORD:
TE
LOGIC "0"
LOGIC "1"
BPW
1 2
13 14 15
4 5 6
Preamble
Stop bit
Start bit
16
1 3
2 4
Sync
Encrypted
Data
Guard
Time
Fixed Code
Data
CODE WORD
FIGURE 4-3:
CODE WORD ORGANIZATION (RIGHT-MOST BIT IS CLOCKED OUT FIRST)
Fixed Code Data
CRC
(2 bit)
VLOW
(1 bit)
Button
Status
(4 bits)
Encrypted Code Data
28-bit
Serial Number
Button
Status
(4 bits)
Discrimination
bits
(12 bits)
MSB
CRC
(2 bit)
VLOW
bit
 1996 Microchip Technology Inc.
+
Serial Number and
Button Status (32 bits)
Preliminary
+
16-bit
Synch Value
LSB
32 bits of Encrypted Data
67 bits
of Data
Transmitted
DS40152C-page 11
HCS360
5.0
SPECIAL FEATURES
5.4
5.1
Code Word Completion
In order to increase the level of security in a system, it is
possible for the receiver to implement what is known as
a secure learning function. This can be done by utilizing
the seed value on the HCS360 which is stored in
EEPROM. Instead of the normal key generation method
being used to create the encryption key, this seed value
is used and there should not be any mathematical relationship between serial numbers and seeds for the best
security.
Code word completion is an automatic feature that
ensures that the entire code word is transmitted, even
if the button is released before the transmission is complete and that a minimum of two words are completed.
The HCS360 encoder powers itself up when a button is
pushed and powers itself down after two complete
words are transmitted if the user has already released
the button. If the button is held down beyond the time
for one transmission, then multiple transmissions will
result. If another button is activated during a
transmission, the active transmission will be aborted
and the new code will be generated using the new
button information.
5.2
Long Guard Time
Federal Communications Commission (FCC) part 15
rules specify the limits on fundamental power and
harmonics that can be transmitted. Power is calculated
on the worst case average power transmitted in a
100ms window. It is therefore advantageous to
minimize the duty cycle of the transmitted word. This
can be achieved by minimizing the duty cycle of the
individual bits and by extending the guard time between
transmissions. long guard time (LNGRD) is used for
reducing the average power of a transmission. This is a
selectable feature. Using the LNGRD allows the user to
transmit a higher amplitude transmission if the
transmission time per 100 ms is shorter. The FCC puts
constraints on the average power that can be
transmitted by a device, and LNGRD effectively
prevents continuous transmission by only allowing the
transmission of every second word. This reduces the
average power transmitted and hence, assists in FCC
approval of a transmitter device.
5.3
5.5
Secure Learning
Auto-shutoff
The Auto-shutoff function automatically stops the
device from transmitting if a button inadvertently gets
pressed for a long period of time. This will prevent the
device from draining the battery if a button gets pressed
while the transmitter is in a pocket or purse. This function can be enabled or disabled and is selected by setting or clearing the time-out bit (Section 3.5.5). Setting
this bit will enable the function (turn Auto-shutoff function on) and clearing the bit will disable the function.
Time-out period is approximately 25 seconds.
5.6
VLOW: Voltage LOW Indicator
The VLOW bit is transmitted with every transmission
(Figure 4-2) and will be transmitted as a one if the
operating voltage has dropped below the low voltage
trip point, approximately 3.8V at 25°C. This VLOW signal
is transmitted so the receiver can give an indication to
the user that the transmitter battery is low.
5.7
LED Output Operation
During normal transmission the LED output is LOW. If
the supply voltage drops below the low voltage trip
point, the LED output will be toggled at approximately
1Hz during the transmission.
CRC (Cycle Redundancy Check) Bits
The CRC bits are calculated on the 65 previously transmitted bits. The CRC bits can be used by the receiver
to check the data integrity before processing starts. The
CRC can detect all single bit and 66% of double bit
errors. The CRC is computed as follows:
EQUATION 5-1:
CRC CALCULATION
CRC [ 1 ] n + 1 = CRC [ 0 ] n ∧ Di n
and
CRC [ 0 ] n + 1 = ( CRC [ 0 ] n ∧ Di n ) ∧ CRC [ 1 ] n
with
CRC [ 1, 0 ] 0 = 0
and
Din the nth transmission bit 0 ≤ n ≤ 64
DS40152C-page 12
Preliminary
 1996 Microchip Technology Inc.
HCS360
6.0
PROGRAMMING THE HCS360
loaded, a programming delay is required for the internal
program cycle to complete. The acknowledge can read
back after the programming delay (TWC). After the first
word and its complement have been downloaded, an
automatic bulk write is performed. This delay can take
up to Twc. At the end of the programming cycle, the
device can be verified (Figure 6-2) by reading back the
EEPROM. Reading is done by clocking the S3 line and
reading the data bits on PWM. For security reasons, it
is not possible to execute a verify function without first
programming the EEPROM. A verify operation can
only be done once, immediately following the program cycle.
When using the HCS360 in a system, the user will have
to program some parameters into the device including
the serial number and the secret key before it can be
used. The programming allows the user to input all
192 bits in a serial data stream, which are then stored
internally in EEPROM. Programming will be initiated by
forcing the PWM line high, after the S3 line has been
held high for the appropriate length of time. S0 and S1
should be held low during the entire program cycle
(Table 6-1 and Figure 6-1). The device can then be programmed by clocking in 16 bits at a time, followed by
the word’s complement using S3 or S2 as the clock line
and PWM as the data in line. After each 16-bit word is
FIGURE 6-1:
PROGRAMMING WAVEFORMS
Enter Program
Mode
S2/S3
(Clock)
T1
Bit 0
T2
Bit 1
Acknowledge
TDH
TCLKL
PWM
(Data)
TWC
TCLKH
TDS
Bit 2
Bit 3
Bit 0
Bit 14 Bit 15
Bit 1 Bit 2
Bit 3
Bit 14 Bit 15
Bit 16 Bit 17
Data for Word 1
Data for Word 0 (KEY_0)
Repeat 12 times for each word
Note 1: Unused button inputs to be held to ground during the entire programming sequence.
2: The VDD pin must be taken to ground after a program/verify cycle.
FIGURE 6-2:
VERIFY WAVEFORMS
Begin Verify Cycle Here
End of
Programming Cycle
PWM
(Data)
Bit190 Bit191
Bit 0
TWC
Bit 1 Bit 2
Data in Word 0
Bit 3
Bit 14
Bit 15
Bit 16 Bit 17
Bit190 Bit191
TDV
S2/S3
(Clock)
Note: If a Verify operation is to be done, then it must immediately follow the Program cycle.
TABLE 6-1
PROGRAMMING/VERIFY TIMING REQUIREMENTS
VDD = 5.0V ± 10%
25° C ± 5 °C
Parameter
Symbol
Min.
Max.
Units
Program mode setup time
T2
0
4.0
ms
Hold time 1
T1
9.0
—
ms
TWC
TCLKL
TCLKH
TDS
TDH
TDV
—
25
25
0
18
—
30
—
—
—
—
24
ms
µs
µs
µs
µs
µs
Program cycle time
Clock low time
Clock high time
Data setup time
Data hold time
Data out valid time
 1996 Microchip Technology Inc.
Preliminary
DS40152C-page 13
HCS360
7.0
INTEGRATING THE HCS360
INTO A SYSTEM
FIGURE 7-1:
Use of the HCS360 in a system requires a compatible
decoder. This decoder is typically a microcontroller with
compatible firmware. Firmware routines that accept
transmissions from the HCS360 and decrypt the
hopping code portion of the data stream are available.
These routines provide system designers the means to
develop their own decoding system.
7.1
Learning a Transmitter to a Receiver
In order for a transmitter to be used with a decoder, the
transmitter must first be ‘learned’. Several learning
strategies can be followed in the decoder implementation. When a transmitter is learned to a decoder, it is
suggested that the decoder stores the serial number
and current synchronization value in EEPROM. The
decoder must keep track of these values for every
transmitter that is learned (Figure 7-1). The maximum
number of transmitters that can be learned is only a
function of how much EEPROM memory storage is
available. The decoder must also store the manufacturer’s code in order to learn a transmission transmitter,
although this value will not change in a typical system
so it is usually stored as part of the microcontroller
ROM code. Storing the manufacturer’s code as part of
the ROM code is also better for security reasons.
It must be stated that some learning strategies have
been patented and care must be taken not to infringe.
TYPICAL LEARN SEQUENCE
Enter Learn
Mode
Wait for Reception
of a Valid Code
Generate Key
from Serial Number
Use Generated Key
to Decrypt
Compare Discrimination
Value with Fixed Value
Equal
?
No
Yes
Wait for Reception
of Second Valid Code
Use Generated Key
to Decrypt
Compare Discrimination
Value with Fixed Value
Equal
?
No
Yes
Counters
Sequential
?
Yes
No
Learn successful Store:
Learn
Unsuccessful
Serial number
Encryption key
Synchronization counter
Exit
DS40152C-page 14
Preliminary
 1996 Microchip Technology Inc.
HCS360
7.2
Decoder Operation
7.3
In a typical decoder operation (Figure 7-2), the key generation on the decoder side is done by taking the serial
number from a transmission and combining that with
the manufacturer’s code to create the same secret key
that was used by the transmitter. Once the secret key is
obtained, the rest of the transmission can be decrypted.
The decoder waits for a transmission and immediately
can check the serial number to determine if it is a
learned transmitter. If it is, it takes the encrypted portion
of the transmission and decrypts it using the stored key
It uses the discrimination bits to determine if the
decryption was valid. If everything up to this point is
valid, the synchronization value is evaluated.
FIGURE 7-2:
TYPICAL DECODER
OPERATION
Start
No
Transmission
Received
?
Yes
No
No
The KEELOQ technology features a sophisticated
synchronization technique (Figure 7-3) which does not
require the calculation and storage of future codes. If
the stored counter value for that particular transmitter
and the counter value that was just decrypted are within
a formatted window of say 16, the counter is stored and
the command is executed. If the counter value was not
within the single operation window, but is within the
double operation window of say 32K window, the transmitted synchronization value is stored in temporary
location and it goes back to waiting for another transmission. When the next valid transmission is received,
it will check the new value with the one in temporary
storage. If the two values are sequential, it is assumed
that the counter had just gotten out of the single operation ‘window’, but is now back in sync, so the new synchronization value is stored and the command
executed. If a transmitter has somehow gotten out of
the double operation window, the transmitter will not
work and must be relearned. Since the entire window
rotates after each valid transmission, codes that have
been used are part of the ‘blocked’ (32K) codes and are
no longer valid. This eliminates the possibility of grabbing a previous code and retransmitting to gain entry.
Note:
Does
Serial Number
Match
?
Yes
Decrypt Transmission
Blocked
(32K Codes)
Yes
Execute
Command
and
Update
Counter
Current
Position
Double
Operation
(32K Codes)
No
No
SYNCHRONIZATION WINDOW
Entire Window
rotates to eliminate
use of previously
used codes
Is
Decryption
Valid
?
Is
Counter
Within 16
?
The synchronization method described in
this section is only a typical implementation
and because it is usually implemented in
firmware, it can be altered to fit the needs
of a particular system
FIGURE 7-3:
Yes
No
Synchronization with Decoder
Single Operation
Window (16 Codes)
Is
Counter
Within 32K
?
Yes
Save Counter
in Temp Location
 1996 Microchip Technology Inc.
Preliminary
DS40152C-page 15
HCS360
8.0
ELECTRICAL CHARACTERISTICS
TABLE 8-1
Note:
ABSOLUTE MAXIMUM RATINGS
Symbol
Item
Rating
Units
VDD
Supply voltage
-0.3 to 6.9
V
VIN
Input voltage
-0.3 to VDD + 0.3
V
VOUT
Output voltage
-0.3 to VDD + 0.3
V
IOUT
Max output current
25
mA
TSTG
Storage temperature
-55 to +125
°C (Note)
TLSOL
Lead soldering temp
300
°C (Note)
VESD
ESD rating
4000
V
Stresses above those listed under “ABSOLUTE MAXIMUM RATINGS” may cause permanent damage to the
device.
TABLE 8-2
DC CHARACTERISTICS
Commercial (C):
Industrial
(I):
Tamb = 0°C to +70°C
Tamb = -40°C to +85°C
2.0V < VDD < 3.3
Parameter
Sym.
Operating current (avg)
ICC
Standby current
Min
Auto-shutoff current
ICCS
High level Input voltage
VIH
Low level input voltage
VIL
1
0.3
0.1
ICCS
2,3
Typ
40
0.55VD
Max
3.0 < VDD < 6.6
Min
Typ
1
1.2
VOH
mA
1.0
1.6
0.1
1.0
µA
350
µA
V
D
VDD+0.
3
-0.3
0.15VD
V
75
160
0.55VD
D
VDD+0.
3
-0.3
0.15VD
Low level output voltage
VOL
0.7VDD
Uni
t
0.7
D
High level output voltage
Max
Conditions
VDD = 3.3V
VDD = 6.6V
D
0.7VDD
0.08VD
0.08VD
D
D
V
IOH = -1.0mA, VDD = 2.0V
IOH = -2.0mA, VDD = 6.6V
V
IOL = 1.0mA, VDD = 2.0V
IOL = 2.0mA, VDD = 6.6V
LED sink current
ILED
0.15
1.0
4.0
0.15
1.0
4.0
mA
VLED = 1.5V, VDD = 6.6V
Resistance; S0-S3
RS03
40
60
80
40
60
80
kΩ
VDD=4.0V
Resistance; PWM
RPW
80
120
160
80
120
160
kΩ
VDD=4.0V
M
Note 1: Typical values are at 25°C.
2: Auto-shutoff current specification does not include the current through the input pulldown resistors.
3: Auto-shutoff current is periodically sampled and not 100% tested.
DS40152C-page 16
Preliminary
 1996 Microchip Technology Inc.
HCS360
FIGURE 8-1:
POWER UP AND TRANSMIT TIMING
Button Press
Detect
Code Word Transmission
TBP
TTD
TDB
Code
Word
1
PWM
Code
Word
2
Code
Word
3
Code
Word
n
TTO
Sn
TABLE 8-3
POWER UP AND TRANSMIT TIMING REQUIREMENTS
VDD = +2.0 to 6.6V
Commercial (C): Tamb = 0°C to +70°C
Industrial
(I): Tamb = -40°C to +85°C
Parameter
Symbol
Min
Max
Unit
Remarks
Time to second button press
TBP
10 + Code
Word Time
26 + Code
Word Time
ms
(Note 1)
Transmit delay from button detect
TTD
4.5
26
ms
(Note 2)
Debounce delay
TDB
4.0
13
ms
Auto-shutoff time-out period
TTO
15.0
35
s
(Note 3)
Note 1: TBP is the time in which a second button can be pressed without completion of the first code word and the
intention was to press the combination of buttons.
2: Transmit delay maximum value if the previous transmission was successfully transmitted.
3: The auto shutoff timeout period is not tested.
FIGURE 8-2:
PWM FORMAT (MANCH = 0)
TE TE TE
LOGIC ‘0’
LOGIC ‘1’
TBP
Preamble
TP
FIGURE 8-3:
Header
TH
Encrypted Portion
of Transmission
THOP
Fixed portion of
Transmission
TFIX
Guard
Time
TG
PWM PREAMBLE/HEADER FORMAT
Data Word
Transmission
Preamble
Header
10 TE
32 TE
 1996 Microchip Technology Inc.
Bit 0 Bit 1
Preliminary
DS40152C-page 17
HCS360
FIGURE 8-4:
PWM DATA WORD FORMAT
Serial Number
MSB
LSB
Bit 0
Header
Bit 1
LSB
Function Code
MSB
Bit 30 Bit 31 Bit 32 Bit 33
S0
S1
S2
CRC
VLOW CRC0 CRC1
Bit 58 Bit 59 Bit 60 Bit 61 Bit 62 Bit 63 Bit 64 Bit 65 Bit 66
Guard
Time
Fixed Code Data
Encrypted Data
FIGURE 8-5:
S3
Status
MANCHESTER FORMAT (MANCH = 1)
TE TE
LOGIC ‘0’
LOGIC ‘1’
TBP
FIGURE 8-6:
Encrypted Portion
of Transmission
THOP
Header
TH
Preamble
TP
Fixed portion of
Transmission
TFIX
Guard
Time
TG
MANCHESTER PREAMBLE/HEADER FORMAT
Data Word
Transmission
Preamble
Header
32 TE
FIGURE 8-7:
Bit 0 Bit 1
4 TE
HCS360 NORMALIZED TE VS. TEMP
1.7
Typical
1.6
1.5
TE Max.
1.4
1.3
TE
VDD LEGEND
= 2.0V
= 3.0V
= 6.0V
1.2
1.1
1.0
0.9
0.8
0.7
TE Min.
0.6
-50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90
Temperature °C
DS40152C-page 18
Preliminary
 1996 Microchip Technology Inc.
HCS360
TABLE 8-4
CODE WORD TRANSMISSION TIMING PARAMETERS—PWM MODE
VDD = +2.0V to 6.6V
Commercial (C):Tamb = 0°C to +70°C
Industrial (I):Tamb = -40°C to +85°C
Code Words Transmitted
FAST1 = 0,
FAST0 = 0
FAST1 = 0,
FAST0 = 1
Symbol
Characteristic
Number
of TE
Min.
Typ.
Max.
Number
of TE
Min.
Typ.
TE
Basic pulse element
1
260
400
620
1
130
200
310
TBP
PWM bit pulse width
3
780
1200
1860
3
390
600
930
µs
TP
Preamble duration
32
8.3
12.8
19.8
32
4.2
6.4
9.9
ms
TH
Header duration
10
2.6
4.0
6.2
10
1.3
2.0
3.1
ms
THOP
Hopping code duration
96
25.0
38.4
59.5
96
12.5
19.2
29.8
ms
TFIX
Fixed code duration
105
27.3
42.0
65.1
105
13.7
21.0
32.6
ms
TG
Guard Time (LNGRD = 0)
16
4.2
6.4
9.9
32
4.2
6.4
9.9
ms
—
Total transmit time
259
—
PWM data rate
—
Note:
67.3 103.6 160.6
1282
833
538
Max. Units
µs
275
35.8
55.0
85.3
ms
—
2564
1667
1075
bps
The timing parameters are not tested but derived from the oscillator clock.
VDD = +2.0V to 6.6V
Commercial (C):Tamb = 0°C to +70°C
Industrial (I):Tamb = -40°C to +85°C
Symbol
Characteristic
Code Words Transmitted
FAST1 = 1,
FAST0 = 0
Number
of TE
Min.
Typ.
FAST1 = 1,
FAST0 = 1
Max.
Number
of Te
Basic pulse element
1
130
200
310
1
TE
TBP
PWM bit pulse width
3
390
600
930
3
TP
Preamble duration
32
4.2
6.4
9.9
32
TH
Header duration
10
1.3
2.0
3.1
10
THOP
Hopping code duration
96
12.5
19.2
29.8
96
TFIX
Fixed code duration
105
13.7
21.0
32.6
105
TG
Guard Time (LNGRD = 0)
32
4.2
6.4
9.9
64
—
Total transmit time
275
35.8
55.0
85.3
307
—
PWM data rate
—
2564
1667
1075
—
Note: The timing parameters are not tested but derived from the oscillator clock.
 1996 Microchip Technology Inc.
Preliminary
Min.
Typ.
Max.
Units
65
195
2.1
0.7
6.2
6.8
4.2
20.0
5128
100
300
3.2
1.0
9.6
10.5
6.4
30.7
3333
155
465
5.0
1.6
14.9
16.3
9.9
47.6
2151
µs
µs
ms
ms
ms
ms
ms
ms
bps
DS40152C-page 19
HCS360
TABLE 8-5
CODE WORD TRANSMISSION TIMING PARAMETERS—MANCHESTER MODE
VDD = +2.0V to 6.6V
Commercial (C):Tamb = 0°C to +70°C
Industrial (I):Tamb = -40°C to +85°C
Symbol
Characteristic
Code Words Transmitted
FAST1 = 0,
FAST0 = 0
Number
of TE
Min.
FAST1 = 0,
FAST0 = 1
Typ.
Max.
Number
of Te
Min.
Typ.
Max.
Units
TE
Basic pulse element
1
520
800
1240
1
260
400
620
µs
TP
Preamble duration
32
16.6
25.6
39.7
32
8.3
12.8
19.8
ms
TH
Header duration
4
2.1
3.2
5.0
4
1.0
1.6
2.5
ms
Start bit
2
1.0
1.6
2.5
2
0.5
0.8
1.2
ms
TSTART
THOP
Hopping code duration
64
33.3
51.2
79.4
64
16.6
25.6
39.7
ms
TFIX
Fixed code duration
70
36.4
56.0
86.8
70
18.2
28.0
43.4
ms
Stop bit
2
1.0
1.6
2.5
2
0.5
0.8
1.2
ms
TG
Guard Time (LNGRD = 0)
8
4.2
6.4
9.9
16
4.2
6.4
9.9
ms
—
Total transmit time
182
94.6
145.6
223.7
196
50.76
78.4
121.5
ms
—
Manchester data rate
—
1923
1250
806
—
3846.2
2500
1612.9
bps
TSTOP
Note:
The timing parameters are not tested but derived from the oscillator clock.
VDD = +2.0V to 6.6V
Commercial (C):Tamb = 0°C to +70°C
Industrial (I):Tamb = -40°C to +85°C
Symbol
Characteristic
Code Words Transmitted
FAST1 = 1,
FAST0 = 0
Number
of TE
Min.
Typ.
FAST1 = 1.
FAST0 = 1
Max.
Number
of Te
Basic pulse element
1
260
400
620
1
Preamble duration
32
8.3
12.8
19.8
32
Header duration
4
1.0
1.6
2.5
4
TSTART Start bit
2
0.5
0.8
1.2
2
THOP Hopping code duration
64
16.6
25.6
39.7
64
TFIX
Fixed code duration
70
18.2
28.0
43.4
70
2
0.5
0.8
1.2
2
TSTOP Stop bit
TG
Guard Time (LNGRD = 0)
16
4.2
6.4
9.9
32
—
Total transmit time
196
50.96
78.4
121.5
212
—
Manchester data rate
—
3846.2 2500.0 1612.9
—
Note: The timing parameters are not tested but derived from the oscillator clock.
TE
TP
TH
DS40152C-page 20
Preliminary
Min.
Typ.
Max.
130
200
310
4.2
6.4
9.9
0.5
0.8
1.2
0.3
0.4
0.6
8.3
12.8
19.8
9.1
14.0
21.7
0.3
0.4
0.6
4.2
6.4
9.9
27.6
42.4
65.7
7692.3 5000.0 3225.8
Units
µs
ms
ms
ms
ms
ms
ms
ms
ms
bps
 1996 Microchip Technology Inc.
HCS360
NOTES:
 1996 Microchip Technology Inc.
Preliminary
DS40152C-page 21
HCS360
NOTES:
DS40152C-page 22
Preliminary
 1996 Microchip Technology Inc.
HCS360
HCS360 PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.
HCS360
—
/P
Package:
Temperature
Range:
Device:
P = Plastic DIP (300 mil Body), 8-lead
SN = Plastic SOIC (150 mil Body), 8-lead
Blank = 0˚C to +70˚C
I = –40˚C to +85˚C
HCS360
HCS360T
Code Hopping Encoder
Code Hopping Encoder (Tape and Reel)
Sales and Support
Data Sheets
Products supported by a preliminary Data Sheet may have an errata sheet describing minor operational differences and recommended workarounds. To determine if an errata sheet exists for a particular device, please contact one of the following:
1. Your local Microchip sales office (see last page)
2. The Microchip Corporate Literature Center U.S. FAX: (602) 786-7277
3. The Microchip’s Bulletin Board, via your local CompuServe number (CompuServe membership NOT required).
Please specify which device, revision of silicon and Data Sheet (include Literature #) you are using.
 1996 Microchip Technology Inc.
Preliminary
DS40152C-page 23
WORLDWIDE SALES & SERVICE
AMERICAS
ASIA/PACIFIC
EUROPE
Corporate Office
Hong Kong
United Kingdom
Microchip Technology Inc.
2355 West Chandler Blvd.
Chandler, AZ 85224-6199
Tel: 602-786-7200 Fax: 602-786-7277
Technical Support: 602 786-7627
Web: http://www.microchip.com
Microchip Asia Pacific
RM 3801B, Tower Two
Metroplaza
223 Hing Fong Road
Kwai Fong, N.T., Hong Kong
Tel: 852-2-401-1200 Fax: 852-2-401-3431
Arizona Microchip Technology Ltd.
Unit 6, The Courtyard
Meadow Bank, Furlong Road
Bourne End, Buckinghamshire SL8 5AJ
Tel: 44-1628-851077 Fax: 44-1628-850259
Atlanta
India
Microchip Technology Inc.
500 Sugar Mill Road, Suite 200B
Atlanta, GA 30350
Tel: 770-640-0034 Fax: 770-640-0307
Microchip Technology India
No. 6, Legacy, Convent Road
Bangalore 560 025, India
Tel: 91-80-299-4036 Fax: 91-80-559-9840
Arizona Microchip Technology SARL
Zone Industrielle de la Bonde
2 Rue du Buisson aux Fraises
91300 Massy, France
Tel: 33-1-69-53-63-20 Fax: 33-1-69-30-90-79
Boston
Korea
Germany
Microchip Technology Inc.
5 Mount Royal Avenue
Marlborough, MA 01752
Tel: 508-480-9990 Fax: 508-480-8575
Microchip Technology Korea
168-1, Youngbo Bldg. 3 Floor
Samsung-Dong, Kangnam-Ku
Seoul, Korea
Tel: 82-2-554-7200 Fax: 82-2-558-5934
Arizona Microchip Technology GmbH
Gustav-Heinemann-Ring 125
D-81739 Müchen, Germany
Tel: 49-89-627-144 0 Fax: 49-89-627-144-44
Shanghai
Arizona Microchip Technology SRL
Centro Direzionale Colleone
Palazzo Taurus 1 V. Le Colleoni 1
20041 Agrate Brianza
Milan, Italy
Tel: 39-39-6899939 Fax: 39-39-6899883
Chicago
Microchip Technology Inc.
333 Pierce Road, Suite 180
Itasca, IL 60143
Tel: 708-285-0071 Fax: 708-285-0075
Microchip Technology
RM 406 Shanghai Golden Bridge Bldg.
2077 Yan’an Road West, Hongiao District
Shanghai, PRC 200335
Tel: 86-21-6275-5700
Fax: 86 21-6275-5060
Dallas
Microchip Technology Inc.
14651 Dallas Parkway, Suite 816
Dallas, TX 75240-8809
Tel: 972-991-7177 Fax: 972-991-8588
France
Italy
Singapore
Microchip Technology Taiwan
Singapore Branch
200 Middle Road
#10-03 Prime Centre
Singapore 188980
Tel: 65-334-8870 Fax: 65-334-8850
Dayton
Microchip Technology Inc.
Two Prestige Place, Suite 150
Miamisburg, OH 45342
Tel: 937-291-1654 Fax: 937-291-9175
Taiwan, R.O.C
Los Angeles
Microchip Technology Taiwan
10F-1C 207
Tung Hua North Road
Taipei, Taiwan, ROC
Tel: 886 2-717-7175 Fax: 886-2-545-0139
Microchip Technology Inc.
18201 Von Karman, Suite 1090
Irvine, CA 92612
Tel: 714-263-1888 Fax: 714-263-1338
New York
JAPAN
Microchip Technology Intl. Inc.
Benex S-1 6F
3-18-20, Shin Yokohama
Kohoku-Ku, Yokohama
Kanagawa 222 Japan
Tel: 81-4-5471- 6166 Fax: 81-4-5471-6122
1/14/97
Microchip Technology Inc.
150 Motor Parkway, Suite 416
Hauppauge, NY 11788
Tel: 516-273-5305 Fax: 516-273-5335
San Jose
Microchip Technology Inc.
2107 North First Street, Suite 590
San Jose, CA 95131
Tel: 408-436-7950 Fax: 408-436-7955
Toronto
Microchip Technology Inc.
5925 Airport Road, Suite 200
Mississauga, Ontario L4V 1W1, Canada
Tel: 905-405-6279 Fax: 905-405-6253
M
All rights reserved. © 1997, Microchip Technology Incorporated, USA. 1/97
Printed on recycled paper.
Information contained in this publication regarding device applications and the like is intended for suggestion only and may be superseded by updates. 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 components in life support systems is not authorized except with express
written approval by Microchip. No licenses are conveyed, implicitly or otherwise, under any intellectual property rights. The Microchip logo and name are registered trademarks
of Microchip Technology Inc. in the U.S.A. and other countries. All rights reserved. All other trademarks mentioned herein are the property of their respective companies.
DS40152C-page 24
Preliminary
 1997 Microchip Technology Inc.