AT88SC1616C-SH ATMEL [ATMEL Corporation], AT88SC1616C-SH Datasheet - Page 12

• Manufacturer Part Number: AT88SC1616C-SH
• Description: Atmel CryptoMemory, 16Kbit
• Manufacturer: ATMEL [ATMEL Corporation]

11.
11.1
11.2
Security Options
Anti-tearing
In the event of a power loss during a write cycle, the integrity of the device’s stored data may be recovered. This function is
optional – the host may choose to activate the anti-tearing function, depending on application requirements. When anti-tearing
is active, write commands take longer to execute, since more write cycles are required to complete them, and data are limited
to eight bytes.
Data are written first to a buffer zone in EEPROM instead of the intended destination address, but with the same access
conditions. The data are then written in the required location. If this second write cycle is interrupted due to a power loss, the
device will automatically recover the data from the system buffer zone at the next power-up.
In two-wire mode, the host is required to perform ACK polling for up to 8mS after write commands when anti-tearing is active.
At power-up, the host is required to perform ACK polling, in some cases for up to 2mS, in the event that the device needs to
carry out the data recovery process.
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:
Table 11-1. Write Lock Example
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 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.
Address
$080
The write lock byte at $080 controls the bytes from $080 to $087
11011001
$0
xxxx xxxx
locked
$1
xxxx xxxx
locked
$2
xxxx xxxx
Atmel AT88SC1616C [SUMMARY DATASHEET]
$3
xxxx xxxx
$4
xxxx xxxx
locked
$5
2030LS−CRYPTO−12/11
xxxx xxxx
$6
xxxx xxxx
$7
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