AT45DB321C-RU datasheet(10/40 Pages) ATMEL

10 / 40 page

3387L–DFLASH–6/06

AT45DB321C

Software Sector Protection is useful in applications in which the WP pin is not or cannot be con-

trolled by a host processor. In such instances, the WP pin may be left floating (the WP pin is

pulled high internally) and sector protection can be controlled using the software commands.

If the device is power cycled, then the Software Sector Protection will be disabled. Once the

device is powered up, the Enable Sector Protection command should be reissued if sector pro-

tection is desired and if the WP pin is not used. The RESET pin has no effect on the Software

Sector Protection.

6.2

Hardware Sector Protection

Sectors specified for protection in Sector Protection Register can be protected from program

and erase operations by utilizing the Write Protection (WP) pin. The protection can be enabled

by asserting the WP pin and keeping the pin in its asserted state. Any sector specified for pro-

tection cannot be erased or reprogrammed as long as the WP pin is asserted. The protection

can be disabled by deasserting the WP pin high. A filter is provided on the WP pin to help protect

against spurious noise on the WP pin. Hardware Sector Protection will provide continuous pro-

tection, based on the contents of the Sector Protection Register, in an application where WP is

always driven low. Please read “Write Protect (WP)” on page 15 for more information.

6.3

Sector Protection Register

Sector Protection Register is a nonvolatile register that contains 16 bytes of data, as shown

below:

Note:

1. Default value for devices shipped from Atmel is 00H.

Sector Number

0 (0a, 0b)

1 to 15

Protected

See Below

FFH

Unprotected

00H

Table 6-1.

Sector 0 (0a, 0b):

(Page 0-7)

(Page 8-511)

Bit 0, 1

Data

Value

Bit 6, 7

Bit 4, 5

Bit 2, 3

Sectors 0a, 0b

Unprotected

00H

Protect Sector 0a

(Page 0-7)

C0H

Protect Sector 0b

(Page 8-511)

3CH

Protect Sectors 0a, 0b

(Page 0-511)

FCH

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