at88sc0104c ATMEL Corporation, at88sc0104c Datasheet - Page 19

• Manufacturer Part Number: at88sc0104c
• Description: Cryptomemory Specification For Standard Mode Of Operation
• Manufacturer: ATMEL Corporation

5.2.4
5.3
5.3.1
5210A–SMIC–04/07
Configuration Memory Values
Anti-tearing (Power Loss Protection)
Default Values
Write Lock is available for any user zone and is selectable by configuring appropriate access
registers. Furthermore, configuring a user zone with the Write Lock option restricts writing to
that zone to a byte at a time. Attempts to write several bytes within a command results in writing
only the first byte.
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 and the host may choose to activate the anti-tearing func-
tion for any write to a user zone or configuration memory by use of the appropriate B4 system
write command. When anti-tearing is active, write commands will take longer to execute since
more write cycles are required. Additionally, the data written is limited to 8 bytes.
Data is written first to a buffer zone in EEPROM instead of the intended destination address in
the user zone or configuration memory, but with the same access conditions. If this write cycle
is interrupted the original data remains in tact in the user zone or configuration memory. The
data is then written in the required memory location. If this second write cycle is interrupted the
device will automatically recover the data from the system buffer zone at the next power-up and
write it to the intended destination address.
In two-wire mode, the host is required to perform ack polling for 28ms after write commands
when anti-tearing is active. At power-up five clock cycles are required to check the anti-tearing
flags. In the event that the device needs to carry out the data recovery process the host is
required to perform ack polling for 14ms.
This section describes each individual field in the configuration memory.
Atmel programs certain fields of the configuration memory at the factory. The customer may
elect to change the content of all of these fields except for the Lot History Code field, which is
permanently locked. Atmel programs the remainder of the fields, including all of the configura-
tion memory and user zones to ones prior to releasing the device from the factory.
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field follows.
AT88SC0104/0204/0404/0808/1616/3216/6416/12816/25616C
summarizes device fields Atmel programs at the factory. A brief description of each
Table 5-2 on
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