- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄371783 > HCS370TIST (Microchip Technology Inc.) KEELOQ Code Hopping Encoder PDF資料下載
參數(shù)資料
| 型號： | HCS370TIST |
| 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)： | 19/36頁 |
| 文件大?。?/td> | 518K |
| 代理商： | HCS370TIST |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁當(dāng)前第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁
2002 Microchip Technology Inc.
Preliminary
DS41111D-page 19
HCS370
7.2
Decoder Operation
Figure 7-2 summarizes normal decoder operation. The
decoder waits until a transmission is received. The
received serial number is compared to the EEPROM
table of learned transmitters to first determine if this
transmitter’s use is allowed in the system. If from a
learned transmitter, the transmission is decrypted
using the stored crypt key and authenticated via the
discrimination bits for appropriate crypt key usage. If
the decryption was valid the synchronization value is
evaluated.
FIGURE 7-2:
TYPICAL DECODER
OPERATION
7.3
Synchronization with Decoder
(Evaluating the Counter)
The K
EE
L
OQ
technology patent scope includes a
sophisticated synchronization technique that does not
require the calculation and storage of future codes. The
technique securely blocks invalid transmissions while
providing transparent resynchronization to transmitters
inadvertently activated away from the receiver.
Figure 7-3 shows a 3-partition, rotating synchronization
window. The size of each window is optional but the
technique is fundamental. Each time a transmission is
authenticated, the intended function is executed and
the transmission’s synchronization counter value is
stored in EEPROM. From the currently stored counter
value there is an initial "Single Operation" forward win-
dow of 16 codes. If the difference between a received
synchronization counter and the last stored counter is
within 16, the intended function will be executed on the
single button press and the new synchronization
counter will be stored. Storing the new synchronization
counter value effectively rotates the entire synchroniza-
tion window.
A "Double Operation" (resynchronization) window fur-
ther exists from the “Single Operation” window up to
32K codes forward of the currently stored counter
value. It is referred to as "Double Operation" because a
transmission with synchronization counter value in this
window will require an additional, sequential counter
transmission prior to executing the intended function.
Upon receiving the sequential transmission the
decoder executes the intended function and stores the
synchronization counter value. This resynchronization
occurs transparently to the user as it is human nature
to press the button a second time if the first was unsuc-
cessful.
The third window is a "Blocked Window" ranging from
the double operation window to the currently stored
synchronization counter value. Any transmission with
synchronization counter value within this window will
be ignored. This window excludes previously used,
perhaps code grabbed transmissions from accessing
the system.
Transmission
Received
Does
Serial Number
Match
Decrypt Transmission
Is
Decryption
Valid
Is
Counter
Within 16
Is
Counter
Within 32K
Uand
Counter
Execute
Command
Save Counter
in Temp Location
Start
No
No
No
No
Yes
Yes
Yes
Yes
Yes
No
No
Note:
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.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| HCS370TP | KEELOQ Code Hopping Encoder |
| HCS370TSL | KEELOQ Code Hopping Encoder |
| HCS370TST | KEELOQ Code Hopping Encoder |
| HCS374HMSR | Radiation Hardened Octal D-Type Flip-Flop, Three-State, Positive Edge Triggered |
| HCS374MS | Radiation Hardened Octal D-Type Flip-Flop, Three-State, Positive Edge Triggered(三態(tài),正邊沿觸發(fā),抗輻射八D觸發(fā)器) |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| HCS370TP | 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:KEELOQ Code Hopping Encoder |
| HCS370TSL | 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:KEELOQ Code Hopping Encoder |
| HCS370TST | 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:KEELOQ Code Hopping Encoder |
| HCS373DMSR | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:8-Bit D-Type Latch |
| HCS373DTR | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:Radiation Hardened Octal Transparent Latch, Three-State |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。