hcs362 Microchip Technology Inc., hcs362 Datasheet - Page 15

• Manufacturer Part Number: hcs362
• Description: Keeloq Code Hopping Encoder
• Manufacturer: Microchip Technology Inc.

4.0
The HCS362 contains 288 bits (18 x 16-bit words) of
EEPROM memory (Table 4-1). This EEPROM array is
used to store the encryption key information and
synchronization value. Further descriptions of the
memory array is given in the following sections.
TABLE 4-1:
Address
2002 Microchip Technology Inc.
Word
10
12
13
14
15
16
17
11
0
1
2
3
4
5
6
7
8
9
EEPROM MEMORY
ORGANIZATION
CONFIG_0
CONFIG_1
SERIAL_0
SERIAL_1
KEY1_0
KEY1_1
KEY1_2
KEY1_3
KEY2_0
KEY2_1
KEY2_2
KEY2_3
SEED_0
SEED_1
SEED_2
SEED_3
SYNC
Field
RES
EEPROM MEMORY MAP
Synchronization counter
Reserved – Set to zero
64-bit Encryption Key1
64-bit Encryption Key1
64-bit Encryption Key1
64-bit Encryption Key1
64-bit Encryption Key2
64-bit Encryption Key2
64-bit Encryption Key2
64-bit Encryption Key2
Seed value (Word 0)
Seed value (Word 1)
Seed value (Word 2)
Seed value (Word 3)
Configuration Word
Configuration Word
Serial Number
Serial Number
(Word 3) MSB
(Word 3) MSB
(Word 1) MSB
(Word 0) LSB
(Word 0) LSB
(Word 0) LSB
Description
(Word 1)
(Word 2)
(Word 1)
(Word 2)
(Word 0)
(Word 1)
MSB
LSB
Preliminary
4.1
The 64-bit crypt key is used to create the encrypted
message transmitted to the receiver. This key is calcu-
lated and programmed during production using a key
generation algorithm. The key generation algorithm
may be different from the K
the key generation algorithm are typically the transmit-
ter’s serial number and the 64-bit 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
decryption purposes.
4.2
This is the 16-bit synchronization value that is used to
create the hopping code for transmission. This value
will be incremented after every transmission.
4.3
This is the four word (60 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 dif-
ferent key generation/tracking process or purely as a
fixed code transmission.
4.4
SER_0
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.
Note:
same
and
KEY_0 - KEY_3
(64-bit Crypt Key)
SYNC (Synchronization Counter)
SEED_0, SEED_1, SEED_2,
and SEED 3 (Seed Word)
SERIAL_0, SERIAL_1
(Encoder Serial Number)
Upper four Significant bits of SEED_3 con-
tains extra configuration information (see
Table 4-4).
SER_1
means
are the lower and upper words of
of
EE
creating
L
OQ
HCS362
algorithm. Inputs to
DS40189D-page 15
the
key
for