AT88SC25616C-MP 查看數據表（PDF） - Atmel Corporation
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AT88SC25616C-MP Datasheet PDF : 18 Pages
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Figure 12. Write Lock Example
AT88SC25616C
Address
$080
$0
11011001
$1
xxxx xxxx
locked
$2
xxxx xxxx
locked
$3
xxxx xxxx
$4
xxxx xxxx
$5
xxxx xxxx
locked
$6
xxxx xxxx
$7
xxxx xxxx
Password
Verification
Authentication
Protocol
The write lock byte may also be locked by writing its least significant (rightmost) bit to “0”. More-
over, when write lock mode is activated, the write lock byte can only be programmed – 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.
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 pass-
word 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.
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 authentication 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 verification or authentica-
tion process will not be taken into account.
Figure 13. Password and Authentication Operations
5017HS–SMEM–11/08
VERIFY RPW
DATA
Checksum (CS)
VERIFY CS
Write DATA
VERIFY CS
CS
11
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