AT45DB321C-TI 查看數據表（PDF） - Atmel Corporation
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AT45DB321C-TI Datasheet PDF : 40 Pages
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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:
Sector Number
Protected
Unprotected
0 (0a, 0b)
See Below
1 to 15
FFH
00H
Table 6-1. Sector 0 (0a, 0b):
0a
(Page 0-7)
0b
(Page 8-511)
Bit 6, 7
Bit 4, 5
Bit 2, 3
Sectors 0a, 0b
Unprotected
00
00
00
Protect Sector 0a
(Page 0-7)
11
00
00
Protect Sector 0b
(Page 8-511)
00
11
11
Protect Sectors 0a, 0b
(Page 0-511)
11
11
11
Note: 1. Default value for devices shipped from Atmel is 00H.
Bit 0, 1
00
00
00
00
Data
Value
00H
C0H
3CH
FCH
10 AT45DB321C
3387M–DFLASH–2/08
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