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AT25DL081 [DATASHEET]

8732D–DFLASH–12/2012

Figure 10-1. Sector Lockdown

10.2 Freeze Sector Lockdown State

The current sector lockdown state can be permanently frozen so that no further modifications to the Sector Lockdown

Registers can be made; therefore, the Sector Lockdown command will be permanently disabled and no additional

sectors can be locked down aside from those already locked down. Any attempts to issue the Sector Lockdown

command after the sector lockdown state has been frozen will be ignored.

Before the Freeze Sector Lockdown State command can be issued, the Write Enable command must have been

previously issued to set the WEL bit in the Status Register to a Logical 1. In addition, the Sector Lockdown Enabled

(SLE) bit in the Status Register must have also been previously set to the Logical 1 state. To issue the Freeze Sector

Lockdown State command, the

CS pin must first be asserted and then the opcode 34h must be clocked into the device

followed by three command-specific address bytes of 55AA40h. After the three address bytes have been clocked in, a

confirmation byte of D0h must be clocked in immediately following the three address bytes. Any additional data clocked

into the device will be ignored. When the

CS pin is deasserted, the current sector lockdown state will be permanently

frozen within a time of t

LOCK

. In addition, the WEL bit in the Status Register will be reset back to the Logical 0 state, and

the SLE bit will be permanently reset to a Logical 0 to indicate that the Sector Lockdown command is permanently

disabled.

The three complete and correct address bytes and the confirmation byte must be clocked into the device before the

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. When the device aborts the Freeze Sector Lockdown State operation, the WEL bit in the

Status Register will be reset to a Logical 0; however, the state of the SLE bit will be unchanged.

Figure 10-2. Freeze Sector Lockdown State

SCK

MSB MSB

2310

00110011

6754983937 3833 36353431 3229 30

Opcode

High-impedance

AA AAAA

MSB

11010000

Address Bits A23-A0 Confirmation Byte In

SCK