AT88SC0808CA-TU Atmel, AT88SC0808CA-TU Datasheet - Page 12

• Manufacturer Part Number: AT88SC0808CA-TU
• Manufacturer: Atmel

Specifications of AT88SC0808CA-TU

• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Mounting: Surface Mount
• Pin Count: 8
• Operating Temperature Classification: Industrial
• Lead Free Status / RoHS Status: Compliant

12.2
Figure 12-1. Write Lock Example
12.3
13. Authentication Protocol
12
Address
$080
Write Lock
Password Verification
AT88SC0808CA [Preliminary]
11011001
$0
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. For example, the write lock byte at
$080 controls the bytes from $081 to $087.
The Write-Lock byte itself may 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 programmed – that
is, bits written to “0” cannot return to “1”.
In the write lock configuration, write operations are limited to writing only one byte at a time.
Attempts to write more than one byte will result in writing of just the first byte into 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.
Presenting the correct WRITE password also grants READ access privileges.
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.
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 vali-
dated, the card loses its previous authentication which must be presented again to gain access.
Only the latest request is memorized.
xxxx xxxx
locked
$1
xxxx xxxx
locked
$2
xxxx xxxx
$3
xxxx xxxx
$4
xxxx xxxx
locked
$5
xxxx xxxx
$6
5204AS–CRYPT–6/08
xxxx xxxx
$7