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The Top Boot Lock (TBL#) and Write Protect (WP#) pins are provided for hardware write protection of device memory in the SST49LF00xA. The TBL# pin is used to write protect 16 boot sectors (64 KByte) at the highest flash memory address range for the SST49LF003A/004A/008A and 4 boot sectors (16 KByte) for SST49LF002A. WP# pin write protects the remaining sectors in the flash memory. An active low signal at the TBL# pin prevents Program and Erase operations of the top boot sectors. When TBL# pin is held high, write protection of the top boot sectors is then

determined by the Boot Block Locking register. The WP# pin serves the same function for the remaining sectors of the device memory. The TBL# and WP# pins write protection functions operate independently of one another.