18

AT25DF161

Figure 8-8.

Program/Erase Resume

9.

Protection Commands and Features

9.1

Write Enable

The Write Enable command is used to set the Write Enable Latch (WEL) bit in the Status Register to a logical “1” state.

The WEL bit must be set before a Byte/Page Program, erase, Protect Sector, Unprotect Sector, Sector Lockdown, Freeze

Sector Lockdown State, Program OTP Security Register, or Write Status Register command can be executed. This makes

the issuance of these commands a two step process, thereby reducing the chances of a command being accidentally or

erroneously executed. If the WEL bit in the Status Register is not set prior to the issuance of one of these commands, then

the command will not be executed.

To issue the Write Enable command, the CS pin must first be asserted and the opcode of 06h must be clocked into the

device. No address bytes need to be clocked into the device, and any data clocked in after the opcode will be ignored.

When the CS pin is deasserted, the WEL bit in the Status Register will be set to a logical “1”. The complete opcode must

be clocked into the device before the CS pin is deasserted, and the CS pin must be deasserted on an even byte boundary

(multiples of eight bits); otherwise, the device will abort the operation and the state of the WEL bit will not change.

Figure 9-1.

Write Enable

SO

SI

SCK

CS

SO

SI

SCK

CS

3687H–DFLASH–5/2013