15

3633C–DFLASH–08/06

AT26DF321 [Preliminary]

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 Status Register will perform a Global Unpro-

tect without changing the state of the SPRL bit. Similarly, writing a 7Fh to 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 Data

Protection Operation

New

SPRL

Value

Bit

7 6 5 4 3 2 1 0

00

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).

10

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

11

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 1. Therefore,

a Global Protect/Unprotect will not occur. However, the

SPRL bit can be changed back to a 0 from a 1 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 1 to a 0.

0

0

0

0

0

1

1

1

1

1