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3686I–DFLASH–02/2019

AT25DF321A

Essentially, if the SPRL bit of the Status Register is in the logical “0” state (Sector Protection Registers are not locked), then

writing a 00h to the first byte of the Status Register will perform a Global Unprotect without changing the state of the SPRL

bit. Similarly, writing a 7Fh to the first byte of the Status Register will perform a Global Protect and keep the SPRL bit in the

logical “0” state. The SPRL bit can, of course, be changed to a logical “1” by writing an FFh if software-locking or hardware-

locking is desired along with the Global Protect.

Table 9-2. Valid SPRL and Global Protect/Unprotect Conditions

WP

State

Current

SPRL

Value

New Write Status

Register Byte 1

Data

Protection Operation

New

SPRL

Value

Bit

7 6 5 4 3 2 1 0

0

0

0 x 0 0 0 0 x x

0 x 0 0 0 1 x x

?

0 x 1 1 1 0 x x

0 x 1 1 1 1 x x

1 x 0 0 0 0 x x

1 x 0 0 0 1 x x

?

1 x 1 1 1 0 x x

1 x 1 1 1 1 x x

Global Unprotect – all Sector Protection Registers reset to 0

No change to current protection

No change to current protection

No change to current protection

Global Protect – all Sector Protection Registers set to 1

Global Unprotect – all Sector Protection Registers reset to 0

No change to current protection

No change to current protection

No change to current protection

Global Protect – all Sector Protection Registers set to 1

0

0

0

0

0

1

1

1

1

1

0

1

x x x x x x x x

No change to the current protection level. All sectors currently protected will remain protected

and all sectors currently unprotected will remain unprotected

The Sector Protection Registers are hard-locked and cannot be changed when the WP pin is

LOW and the current state of SPRL is 1. Therefore, a Global Protect/Unprotect will not occur. In

addition, the SPRL bit cannot be changed (the WP pin must be HIGH in order to change SPRL

back to a 0)

1

0

0 x 0 0 0 0 x x

0 x 0 0 0 1 x x

?

0 x 1 1 1 0 x x

0 x 1 1 1 1 x x

1 x 0 0 0 0 x x

1 x 0 0 0 1 x x

?

1 x 1 1 1 0 x x

1 x 1 1 1 1 x x

Global Unprotect – all Sector Protection Registers reset to 0

No change to current protection

No change to current protection

No change to current protection

Global Protect – all Sector Protection Registers set to 1

Global Unprotect – all Sector Protection Registers reset to 0

No change to current protection

No change to current protection

No change to current protection

Global Protect – all Sector Protection Registers set to 1

0

0

0

0

0

1

1

1

1

1

1

1

0 x 0 0 0 0 x x

0 x 0 0 0 1 x x

?

0 x 1 1 1 0 x x

0 x 1 1 1 1 x x

1 x 0 0 0 0 x x

1 x 0 0 0 1 x x

?

1 x 1 1 1 0 x x

1 x 1 1 1 1 x x

No change to the current protection level. All sectors currently protected will remain

protected, and all sectors currently unprotected will remain unprotected

The Sector Protection Registers are soft-locked and cannot be changed when the

current state of SPRL is one. Therefore, a Global Protect/Unprotect will not occur.

However, the SPRL bit can be changed back to a zero from a one since the WP pin is

HIGH. To perform a Global Protect/Unprotect, the Write Status Register command

must be issued again after the SPRL bit has been changed from a one to a zero.

0

0

0

0

0

1

1

1

1

1