AT34C02-10PU-1.8 ATMEL [ATMEL Corporation], AT34C02-10PU-1.8 Datasheet - Page 10

• Manufacturer Part Number: AT34C02-10PU-1.8
• Description: Two-wire Serial EEPROM with Permanent Software Write Protect
• Manufacturer: ATMEL [ATMEL Corporation]

Write Protection
The software write protection, once enabled, permanently write protects only the first-
half of the array (00H - 7FH) while the hardware write protection, via the WP pin, is used
to protect the entire array.
SOFTWARE WRITE PROTECTION: The software write protection is enabled by send-
ing a command, similar to a normal write command, to the device which programs the
write protect register. This must be done with the WP pin low. The write protect register
is programmed by sending a write command with the device address of 0110 instead of
1010 with the address and data bit being don’t cares (see Figure 7 on page 11). Once
the software write protection has been enabled, the device will no longer acknowledge
the 0110 control byte. The software write protection cannot be reversed even if the
device is powered down. The write cycle time must be observed.
HARDWARE WRITE PROTECTION: The WP pin can be connected to V
, GND, or
CC
left floating. Connecting the WP pin to V
will write protect the entire array, regardless
CC
of whether or not the software write protection has been enabled. The software write
protection register cannot be programmed when the WP pin is connected to V
. If the
CC
WP pin is connected to GND or left floating, the write protection mode is determined by
the status of the software write protect register.
AT34C02
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0958Q–SEEPR–1/07