AT45DB321D-CCU Adesto Technologies, AT45DB321D-CCU Datasheet - Page 15

• 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

8.
8.1
8.1.1
Security Features
Sector Lockdown
The device incorporates a sector lockdown mechanism that allows each individual sector to be permanently locked so that it
becomes read only. This is useful for applications that require the ability to permanently protect a number of sectors against
malicious attempts at altering program code or security information. Once a sector is locked down, it can never be erased or
programmed, and it can never be unlocked.
To issue the sector lockdown command, the CS pin must first be asserted, as it would be for any other command. Once the CS
pin has been asserted, the appropriate four-byte opcode sequence must be clocked into the device in the correct order. The
four-byte opcode sequence must start with 3DH, and be followed by 2AH, 7FH, and 30H. After the last byte of the command
sequence has been clocked in, three address bytes specifying any address within the sector to be locked down must be clocked
into the device. After the last address bit has been clocked in, the CS pin must be deasserted to initiate the internally self-timed
lockdown sequence.
The lockdown sequence should take place in a maximum time of t
is busy. If the device is powered down before the completion of the lockdown sequence, then the lockdown status of the sector
cannot be guaranteed. In this case, it is recommended that the user read the sector lockdown register to determine the status of
the appropriate sector lockdown bits or bytes and reissue the sector lockdown command, if necessary.
Table 8-1.
Figure 8-1. Sector Lockdown
Sector Lockdown Register
The nonvolatile sector lockdown register contains 64 bytes of data, as shown below:
Table 8-2.
Table 8-3.
Command
Sector lockdown
CS
Sector Number
Locked
Unlocked
Sectors 0a, 0b unlocked
Sector 0a locked (pages 0-7)
Sector 0b locked (pages 8-127)
Sectors 0a, 0b locked (pages 0-127)
SI
Each transition
represents 8 bits
Sector Lockdown
Sector Lockdown Register
Sector 0 (0a, 0b)
Opcode
byte 1
Opcode
byte 2
Opcode
byte 3
Byte 1
3DH
(Pages 0-7)
Opcode
Bit 7, 6
byte 4
0a
00
11
00
11
See
P
0 (0a, 0b)
, during which the status register will indicate that the device
Byte 2
Address
Table 8-3
2AH
bytes
(Pages 8-127)
Bit 5, 4
00
00
11
11
0b
Address
bytes
AT45DB321D [DATASHEET]
Byte 3
Bit 3, 2
7FH
00
00
00
00
Address
bytes
3597R–DFLASH–11/2012
Bit 1, 0
1 to 63
FFH
00H
00
00
00
00
Byte 4
30H
Value
C0H
Data
00H
30H
F0H
15