參數(shù)資料
型號： HCS412TI
廠商： Microchip Technology Inc.
英文描述： KEELOQ Code Hopping Encoder and Transponder
中文描述： 而Keeloq跳碼編碼器和轉(zhuǎn)發(fā)器
文件頁數(shù)： 31/44頁
文件大?。?/td> 704K
代理商： HCS412TI
2002 Microchip Technology Inc.
Preliminary
DS41099C-page 31
HCS412
6.0
INTEGRATING THE HCS412
INTO A SYSTEM
Use of the HCS412 in a system requires a compatible
decoder. This decoder is typically a microcontroller with
compatible firmware. Microchip will provide (via a free
license agreement) firmware routines that accept
transmissions from the HCS412 and decrypt the
hopping code portion of the data stream. These
routines provide system designers the means to
develop their own decoding system.
6.1
Learning a Transmitter to a
Receiver
A transmitter must first be ’learned’ by a decoder before
its use is allowed in the system. Several learning strat-
egies are possible, Figure 6-1 details a typical learn
sequence. Core to each, the decoder must minimally
store each learned transmitter’s serial number and cur-
rent synchronization counter value in EEPROM. Addi-
tionally, the decoder typically stores each transmitter’s
unique crypt key. The maximum number of learned
transmitters will therefore be relative to the available
EEPROM.
A transmitter’s serial number is transmitted in the clear
but the synchronization counter only exists in the code
word’s encrypted portion. The decoder obtains the
counter value by decrypting using the same key used
to encrypt the information. The K
EE
L
OQ
algorithm is a
symmetrical block cipher so the encryption and decryp-
tion keys are identical and referred to generally as the
crypt key. The encoder receives its crypt key during
manufacturing. The decoder is programmed with the
ability to generate a crypt key as well as all but one
required input to the key generation routine; typically
the transmitter’s serial number.
Figure 6-1 summarizes a typical learn sequence. The
decoder receives and authenticates a first transmis-
sion; first button press. Authentication involves gener-
ating the appropriate crypt key, decrypting, validating
the correct key usage via the discrimination bits and
buffering the counter value. A second transmission is
received and authenticated. A final check verifies the
counter values were sequential; consecutive button
presses. If the learn sequence is successfully com-
plete, the decoder stores the learned transmitter’s
serial number, current synchronization counter value
and appropriate crypt key. From now on the crypt key
will be retrieved from EEPROM during normal opera-
tion instead of recalculating it for each transmission
received.
Certain learning strategies have been patented and
care must be taken not to infringe.
FIGURE 6-1:
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
Wait for Reception
of Second Valid Code
Compare Discrimination
Value with Fixed Value
Use Generated Key
to Decrypt
Equal
Counters
Sequential
Encryption key
Synchronization counter
Serial number
Exit
Learn successful Store:
Learn
Unsuccessful
No
No
No
Yes
Yes
Yes
相關(guān)PDF資料
PDF描述
HCS412TP Dual PCI 2.2 Hot-Swap Controllers
HCS412 Code Hopping Encoder and Transponder(編碼器和收發(fā)兩用機)
HCS412I +48V Quad Hot-Swap Controllers For Power-Over-LAN
HCS412IP KEELOQ Code Hopping Encoder and Transponder
HCS412TSN KEELOQ Code Hopping Encoder and Transponder
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
HCS412T-I/SN 功能描述:編碼器、解碼器、復(fù)用器和解復(fù)用器 w/ Passive Entry RoHS:否 制造商:Micrel 產(chǎn)品:Multiplexers 邏輯系列:CMOS 位數(shù): 線路數(shù)量（輸入/輸出）:2 / 12 傳播延遲時間:350 ps, 400 ps 電源電壓-最大:2.625 V, 3.6 V 電源電壓-最小:2.375 V, 3 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-44 封裝:Tray
HCS412TP 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:KEELOQ Code Hopping Encoder and Transponder
HCS412TSN 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:KEELOQ Code Hopping Encoder and Transponder
HCS473 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:Code Hopping Encoder and Transponder
HCS473/P 功能描述:編碼器、解碼器、復(fù)用器和解復(fù)用器 w/ Passive Entry RoHS:否 制造商:Micrel 產(chǎn)品:Multiplexers 邏輯系列:CMOS 位數(shù): 線路數(shù)量（輸入/輸出）:2 / 12 傳播延遲時間:350 ps, 400 ps 電源電壓-最大:2.625 V, 3.6 V 電源電壓-最小:2.375 V, 3 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-44 封裝:Tray
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