10

AT34C02

0958Q–SEEPR–1/07

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.

of whether or not the software write protection has been enabled. The software write

WP pin is connected to GND or left floating, the write protection mode is determined by

the status of the software write protect register.