5.4 Write Protection

The Write-Protect (WP) pin allows normal read and write operations when held high. When the WP pin is brought low and WPEN bit is a logic ‘1’, all write operations to the STATUS register are inhibited. If the WP pin goes low while CS is still low, it will interrupt a Write STATUS Register (WRSR) operation. If the internal write cycle has already been initiated, WP going low will have no effect on any write operation to the STATUS register. The WP pin function is blocked when the WPEN bit in the STATUS register is a logic ‘0’. This allows the user to install the AT25128B/AT25256B device in a system with the WP pin tied to ground and still be able to write to the STATUS register. All WP pin functions are enabled when the WPEN bit is set to a logic ‘1’.