AT88SC0104C datasheet(18/58 Pages) ATMEL

18 / 58 page

5210B–SMIC–11/08

AT88SC0104/0204/0404/0808/1616/3216/6416/12816/25616C

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.

5.2.4

Anti-tearing (Power Loss Protection)

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.

5.3

Configuration Memory Values

This section describes each individual field in the configuration memory.

5.3.1

Default Values

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. Table 5-2 on

page 16 summarizes device fields Atmel programs at the factory. A brief description of each

field follows.

AT88SC0104C Datasheet(PDF) 18 Page - ATMEL Corporation