AT45DB321E datasheet(19/70 Pages) DIALOG

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AT45DB321E

8784L–DFLASH–3/2019

Figure 6-2.

Enable Sector Protection

6.14.2 Disable Sector Protection

To disable the sector protection, a 4-byte command sequence of 3Dh, 2Ah, 7Fh, and 9Ah must be clocked into the

device. After the last bit of the opcode sequence has been clocked in, the CS pin must be deasserted to disable the

sector protection.

Table 6-6.

Disable Sector Protection Command

Figure 6-3.

Disable Sector Protection

6.15

Hardware Controlled Protection

Sectors specified for protection in the Sector Protection Register and the Sector Protection Register itself can be

protected from program and erase operations by asserting the WP pin and keeping the pin in its asserted state. The

Sector Protection Register and any sector specified for protection cannot be erased or programmed as long as the WP

pin is asserted. In order to modify the Sector Protection Register, the WP pin must be deasserted. If the WP pin is

permanently connected to GND, then the contents of the Sector Protection Register cannot be changed. If the WP pin is

deasserted or permanently connected to V

CC, then the contents of the Sector Protection Register can be modified.

The WP pin will override the software controlled protection method but only for protecting the sectors.

Example:

If the sectors were not previously protected by the Enable Sector Protection command, then simply

asserting the WP pin would enable the sector protection within the maximum specified t

WPE time. When the

WP pin is deasserted, however, the sector protection would no longer be enabled (after the maximum

specified t

WPD time) as long as the Enable Sector Protection command was not issued while the WP pin was

asserted. If the Enable Sector Protection command was issued before or while the WP pin was asserted,

then simply deasserting the WP pin would not disable the sector protection. In this case, the Disable Sector

Protection command would need to be issued while the WP pin is deasserted to disable the sector

protection. The Disable Sector Protection command is also ignored whenever the WP pin is asserted.

A noise filter is incorporated to help protect against spurious noise that may inadvertently assert or deassert the WP pin.

Figures 6-4 and Table 6-7 detail the sector protection status for various scenarios of the WP pin, the Enable Sector

Protection command, and the Disable Sector Protection command.

3Dh

2Ah

7Fh

A9h

Each transition represents eight bits

Command

Byte 1

Byte 2

Byte 3

Byte 4

Disable Sector Protection

3Dh

2Ah

7Fh

9Ah

3Dh

2Ah

7Fh

9Ah

Each transition represents eight bits

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