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參數(shù)資料
| 型號： | HCS370P |
| 廠商： | Microchip Technology Inc. |
| 英文描述： | KEELOQ Code Hopping Encoder |
| 中文描述： | 而Keeloq跳碼編碼器 |
| 文件頁數(shù)： | 18/36頁 |
| 文件大小： | 518K |
| 代理商： | HCS370P |
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HCS370
DS41111D-page 18
Preliminary
2002 Microchip Technology Inc.
7.0
INTEGRATING THE HCS370
INTO A SYSTEM
Use of the HCS370 in a system requires a compatible
decoder. This decoder is typically a microcontroller with
compatible firmware. Microchip will provide (via a
license agreement) firmware routines that accept
transmissions from the HCS370 and decrypt the
hopping code portion of the data stream. These
routines provide system designers the means to
develop their own decoding system.
7.1
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 7-1 details a typical learn
sequence. The decoder must minimally store each
learned transmitter’s serial number and current syn-
chronization counter value in EEPROM. Additionally,
the decoder typically stores each transmitter’s unique
crypt key. The maximum number of learned transmit-
ters will therefore be relative to the available EEPROM.
A transmitter’s serial number is transmitted in the 32-bit
fixed code, 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
algo-
rithm is a symmetrical block cipher so the encryption
and decryption keys are identical and referred to gen-
erally as the crypt key. The encoder receives its crypt
key during manufacturing. The decoder typically calcu-
lates the crypt key by running the encoder serial num-
ber or seed through the key generation routine.
Figure 7-1 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-
pleted, 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 by 3rd
parties and care must be taken not to infringe.
FIGURE 7-1:
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 |
|---|---|
| HCS370SL | KEELOQ Code Hopping Encoder |
| HCS370ST | KEELOQ Code Hopping Encoder |
| HCS370TIP | KEELOQ Code Hopping Encoder |
| HCS370TISL | KEELOQ Code Hopping Encoder |
| HCS370TIST | KEELOQ Code Hopping Encoder |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| HCS370SL | 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:KEELOQ Code Hopping Encoder |
| HCS370ST | 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:KEELOQ Code Hopping Encoder |
| HCS370T/SL | 功能描述:編碼器、解碼器、復(fù)用器和解復(fù)用器 2-5.5V 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 |
| HCS370T/ST | 功能描述:編碼器、解碼器、復(fù)用器和解復(fù)用器 2-5.5V 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 |
| HCS370T-I/SL | 功能描述:編碼器、解碼器、復(fù)用器和解復(fù)用器 2-5.5V 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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