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AT25SF321

DS-25SF321–047F–8/2017

8.3

Non-Volatile Protection

The device can be software protected against erroneous or malicious program or erase operations by utilizing the Non-

Volatile Protection feature of the device. Non-Volatile Protection can be enabled or disabled by using the Write Status

Register command to change the value of the Protection (CMP, SEC, TB, BP2, BP1, BP0) bits in the Status Register.

The following table outlines the states of the Protection bits and the associated protection area

.

Table 8-1.

Memory Array with CMP=0

Protection Bits

Memory Content

SEC

TB

BP2

BP1

BP0

Address Range

Portion

X

X

0

0

0

None

None

0

0

0

0

1

3F0000h-3FFFFFh

Upper 1/64

0

0

0

1

0

3E0000h-3FFFFFh

Upper 1/32

0

0

0

1

1

3C0000h-3FFFFFh

Upper 1/16

0

0

1

0

0

380000h-3FFFFFh

Upper 1/8

0

0

1

0

1

300000h-3FFFFFh

Upper 1/4

0

0

1

1

0

200000h-3FFFFFh

Upper 1/2

0

1

0

0

1

000000h-00FFFFh

Lower 1/64

0

1

0

1

0

000000h-01FFFFh

Lower 1/32

0

1

0

1

1

000000h-03FFFFh

Lower 1/16

0

1

1

0

0

000000h-07FFFFh

Lower 1/8

0

1

1

0

1

000000h-0FFFFFh

Lower 1/4

0

1

1

1

0

000000h-1FFFFFh

Lower 1/2

X

X

1

1

1

000000h-3FFFFFh

ALL

1

0

0

0

1

3FF000h-3FFFFFh

Upper 1/512

1

0

0

1

0

3FE000h-3FFFFFh

Upper 1/256

1

0

0

1

1

3FC000h-3FFFFFh

Upper 1/128

1

0

1

0

X

3F8000h-3FFFFFh

Upper 1/64

1

0

1

1

0

3F8000h-3FFFFFh

Upper 1/64

1

1

0

0

1

000000h-000FFFh

Lower 1/512

1

1

0

1

0

000000h-001FFFh

Lower 1/256

1

1

0

1

1

000000h-003FFFh

Lower 1/128

1

1

1

0

X

000000h-007FFFh

Lower 1/64

1

1

1

1

0

000000h-007FFFh

Lower 1/64