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參數(shù)資料
| 型號： | SCS152 |
| 廠商： | Microchip Technology Inc. |
| 英文描述： | HM Series Hermetically Sealed Basic Switch, Single Pole Double Throw Circuitry, 0.5 A at 28 Vdc, Integral Lever Actuator, Solder Termination |
| 中文描述： | 而Keeloq令牌卡芯片 |
| 文件頁數(shù)： | 11/16頁 |
| 文件大小： | 182K |
| 代理商： | SCS152 |
SCS152
1997 Microchip Technology Inc.
Preliminary
DS40150B-page 11
5.0
COMPATIBILITY WITH
INDUSTRY STANDARD
DEVICES
The RESET and RDBIT commands meets the require-
ments of ISO 7816-3 for the ‘Answer-to-Reset’
sequence for
synchronous
chip cards.
The basic counter modification commands BITPROG
and ERASE correspond with the WRITE and
ERASE-WITH-CARRY commands of industry standard
devices. However, industry standard devices use eight
bits to represent each digit, and a WRITE command will
program the current bit to ‘0’.
The application can, therefore, decrement a digit by
programming any of the eight bits to ‘0’, whereas with
the SCS152, any BITPROG command will always
decrement the current digit value. If the application
decrements each digit as described above, the WRITE
command will appear to program the current bit to ‘0’.
Thus, while the SCS152 will accept and interpret the
commands correctly, the changes to the memory map
will only correspond to that of the other cards, if the first
‘1’ in a digit field is always programmed ‘0’ with a
WRITE command.
For example, if digit field D3 contains the value ‘6’, it will
be read out as 00111111. If a BITPROG command is
issued anywhere in D3, its value will be decremented to
‘5’, and it will always read out as 00011111, regardless
of which address in the digit the BITPROG command
was issued.
The ISS is only an external view of the CFG field and
cannot be changed. A BITPROG command at this
address will actually decrement digit D4. It should also
be noted that the address counter appears to wrap from
275 back to 0, which differs from other similar devices.
5.1
Fail Safe Counter Update
The carry is performed by a BITPROG, followed by an
ERASE. This process first deducts a number of tokens
(the BITPROG command) and then adds some again
(with the ERASE command), but never more than pre-
viously deducted with the BITPROG command. If the
device is pulled from the reader between the BITPROG
and ERASE commands, the user may lose many
tokens.
This situation can be avoided by substituting the
DECR-ERASE command whenever a sequence of
BITPROG and ERASE commands are needed to
update the token counter (Step 5c in Section 4.2). This
will modify the contents of the EEPROM in one indivis-
ible operation that will either complete or not modify the
EEPROM in any way, if external power is removed early
on during the EEPROM programming.
相關PDF資料 |
PDF描述 |
|---|---|
| SCS152-IS | Small glass bead with axial leads |
| SCS152-IW | Small glass bead with axial leads |
| SCS152-IWF | Small glass bead with axial leads |
| SCS156 | Reloadable Token Card Chip(KeeLoq 表示卡芯片) |
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| SCS-1522B | 制造商:SYNERGY 制造商全稱:SYNERGY MICROWAVE CORPORATION 功能描述:HIGH POWER BI-DIRECTIONAL COUPLERS |
| SCS-1522D | 制造商:SYNERGY 制造商全稱:SYNERGY MICROWAVE CORPORATION 功能描述:HIGH POWER BI-DIRECTIONAL COUPLERS |
| SCS152-IS | 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:KEELOQ Token Card Chip |
| SCS152-IW | 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:KEELOQ Token Card Chip |
| SCS152-IWF | 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:KEELOQ Token Card Chip |
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