AT88SC0104C-PI 데이터 시트보기 (PDF) - Atmel Corporation

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AT88SC0104C-PI

CryptoMemory 1 Kbit

Atmel Corporation 

Write Lock

If a user zone is configured in the write lock mode, the lowest address byte of an 8-byte

page constitutes a write access byte for the bytes of that page.

Example: The write lock byte at $080 controls the bytes from $080 to $087.

$080

11011001

$081

xxxx xxxx

locked

$082

$083

$084

$085

$086

$087

@

xxxx xxxx

locked

xxxx xxxx

xxxx xxxx

xxxx xxxx

locked

xxxx xxxx

xxxx xxxx

$80

The write lock byte may also be locked by writing its least significant (rightmost) bit to

“0”. Moreover, when write lock mode is activated, the write lock byte can only be pro-

grammed — that is, bits written to “0” cannot return to “1”.

In the write lock configuration, only one byte can be written at a time. Even if several

bytes are received, only the first byte will be taken into account by the device.

Password Verification

Passwords may be used to protect read and/or write access of any user zone. When a

valid password is presented, it is memorized and active until power is turned off, unless

a new password is presented or RST becomes active. There are eight password sets

that may be used to protect any user zone. Only one password is active at a time, but

write passwords give read access also.

Authentication Protocol

The access to a user zone may be protected by an authentication protocol. Any one of

four keys may be selected to use with a user zone.

The authentication success is memorized and active as long as the chip is powered,

unless a new authentication is initialized or RST becomes active. If the new authentica-

tion request is not validated, the card loses its previous authentication and it should be

presented again. Only the last request is memorized.

Note:

Password and authentication may be presented at any time and in any order. If the trials

limit has been reached (after four consecutive incorrect attempts), the password verifica-

tion or authentication process will not be taken into account.

Figure 9. Password and Authentication Operations

VERIFY RPW

DATA

Checksum (CS)

VERIFY CS

Write DATA

10 AT88SC0104C

VERIFY CS

CS

2021GS–SMEM–7/06

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