AT45DB642D-CU Atmel, AT45DB642D-CU Datasheet - Page 14

• Manufacturer Part Number: AT45DB642D-CU
• Description: IC FLASH MEM 64MBIT 66MHZ 24BGA
• Manufacturer: Atmel

Specifications of AT45DB642D-CU

• Format - Memory: FLASH
• Memory Type: DataFLASH
• Memory Size: 64M (8192 pages x 1056 bytes)
• Speed: 66MHz
• Interface: Parallel/Serial
• Voltage - Supply: 2.7 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 24-CBGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8.1.3
9. Hardware Controlled Protection
Figure 9-1.
Table 9-1.
14
Period
Time
1
2
3
WP
AT45DB642D
Various Aspects About Software Controlled Protection
WP Pin and Protection Status
WP Pin and Protection Status
WP Pin
High
High
Low
Software controlled protection is useful in applications in which the WP pin is not or cannot be
controlled by a host processor. In such instances, the WP pin may be left floating (the WP pin is
internally pulled high) and sector protection can be controlled using the Enable Sector Protection
and Disable Sector Protection commands.
If the device is power cycled, then the software controlled 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.
Sectors specified for protection in the Sector Protection Register can be protected from program
and erase operations by asserting the WP pin and keeping the pin in its asserted state. Any sec-
tor specified for protection cannot be erased or reprogrammed as long as the WP pin is
asserted.
The WP pin will override the software controlled protection method but only for protecting the
sectors. For example, if the sectors were not previously protected by the Enable Sector Protec-
tion command, then simply asserting the WP pin would enable the sector protection within the
maximum specified t
would no longer be enabled (after the maximum specified t
tor 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 deassert-
ing 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 sec-
tor 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.
The table below details the sector protection status for various scenarios of the WP pin, the
Enable Sector Protection command, and the Disable Sector Protection command.
1
Enable Sector Protection Command
Command Issued During Period 1 or 2
Command Not Issued Previously
Issue Command
Issue Command
WPE
–
X
–
time. When the WP pin is deasserted; however, the sector protection
2
Disable Sector Protection
Issue Command
Issue Command
Not Issued Yet
Command
WPD
X
X
–
–
time) as long as the Enable Sec-
3
Sector Protection
3542K–DFLASH–04/09
Disabled
Disabled
Disabled
Enabled
Enabled
Enabled
Enabled
Status