RFHCS362F-I/SO View Datasheet(PDF) - Microchip Technology
Part Name
Description
MFG CO.
RFHCS362F-I/SO Datasheet PDF : 54 Pages
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rfHCS362G/362F
4.0 EEPROM MEMORY
ORGANIZATION
The rfHCS362G/362F 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 follow-
ing sections.
TABLE 4-1: EEPROM MEMORY MAP
Word
Address
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Field
KEY1_0
KEY1_1
KEY1_2
KEY1_3
KEY2_0
KEY2_1
KEY2_2
KEY2_3
SEED_0
SEED_1
SEED_2
SEED_3
CONFIG_0
CONFIG_1
SERIAL_0
SERIAL_1
SYNC
RES
Description
64-bit Encryption Key1
(Word 0) LSB
64-bit Encryption Key1
(Word 1)
64-bit Encryption Key1
(Word 2)
64-bit Encryption Key1
(Word 3) MSB
64-bit Encryption Key2
(Word 0) LSB
64-bit Encryption Key2
(Word 1)
64-bit Encryption Key2
(Word 2)
64-bit Encryption Key2
(Word 3) MSB
Seed value (Word 0)
LSB
Seed value (Word 1)
Seed value (Word 2)
Seed value (Word 3)
MSB
Configuration Word
(Word 0)
Configuration Word
(Word 1)
Serial Number
(Word 0) LSB
Serial Number
(Word 1) MSB
Synchronization counter
Reserved – Set to zero
4.1 KEY_0 - KEY_3
(64-bit Encryption Key)
The 64-bit encryption key is used to create the
encrypted message. This key is calculated and pro-
grammed during production using a key generation
algorithm. The key generation algorithm may be differ-
ent from the KEELOQ algorithm. Inputs to the key gen-
eration algorithm are typically the transmitter’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.
4.2 SYNC (Synchronization Counter)
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 SEED_0, SEED_1, SEED_2,
and SEED 3 (Seed Word)
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.
Note:
Upper four Significant bits of SEED_3 con-
tains extra configuration information (see
Table 4-5).
4.4 SERIAL_0, SERIAL_1
(Encoder Serial Number)
SERIAL_0 and SERIAL_1 are the lower and upper
words of the device serial number, respectively. There
are 32 bits allocated for the serial number and a select-
able configuration bit determines whether 32 or 28 bits
will be transmitted. The serial number is meant to be
unique for every transmitter.
DS41189B-page 20
© 2011 Microchip Technology Inc.
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