AT45DB321D-CCU Adesto Technologies, AT45DB321D-CCU Datasheet - Page 11

• Manufacturer Part Number: AT45DB321D-CCU
• Description: Flash 32M 2.7-3.6V, 66Mhz Serial Flash
• Manufacturer: Adesto Technologies

Specifications of AT45DB321D-CCU

• Rohs: yes
• Data Bus Width: 8 bit
• Memory Type: Data Flash
• Memory Size: 32 Mbit
• Architecture: Flexible, Uniform Erase
• Timing Type: Synchronous
• Interface Type: SPI
• Supply Voltage - Max: 3.6 V
• Supply Voltage - Min: 2.7 V
• Maximum Operating Current: 15 mA
• Operating Temperature: - 40 C to + 85 C
• Mounting Style: SMD/SMT
• Package / Case: BGA-24
• Factory Pack Quantity: 378

6.1.2
6.1.3
7.
Disable Sector Protection Command
To disable sector protection using the software controlled method, the CS pin must first be asserted, as it would be with any
other command. Once the CS pin has been asserted, the appropriate four-byte sequence for the disable sector protection
command must be clocked in via the input pin (SI). After the last bit of the command sequence has been clocked in, the CS pin
must be deasserted, after which the sector protection will be disabled. The WP pin must be in the deasserted state; otherwise,
the disable sector protection command will be ignored.
Table 6-2.
Figure 6-2. Disable Sector Protection
Various Aspects About Software Controlled Protection
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 protection is desired and if the WP pin is not used.
Hardware Controlled Protection
Sectors specified in the sector protection register for protection, 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 reprogrammed 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 content
of the sector protection register cannot be changed. If the WP pin is deasserted or permanently connected to V
content of the sector protection register can be modified.
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 protection command, then simply asserting the WP pin would enable
sector protection within the maximum specified t
longer be enabled (after the maximum specified t
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 sector protection. In this case, the disable sector protection command
would need to be issued while the WP pin is deasserted to disable 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.
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.
Figure 7-1. WP Pin and Protection Status
Command
Disable sector protection
CS
WP
SI
Each transition
represents 8 bits
Disenable Sector Protection Command
Opcode
Byte 1
1
Opcode
Byte 2
Opcode
Byte 3
WPE
WPD
time. However, when the WP pin is deasserted, sector protection would no
time) as long as the enable sector protection command was not issued
Byte 1
Opcode
Byte 4
3DH
2
Byte 2
2AH
AT45DB321D [DATASHEET]
Byte 3
7FH
3
3597R–DFLASH–11/2012
CC
, then the
Byte 4
9AH
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