AT45DB321E datasheet(23/69 Pages) RENESAS

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AT45DB321E

8784M–DFLASH–02/2022

Figure 7-1.

Sector Lockdown

7.1.1

Read Sector Lockdown Register

The nonvolatile Sector Lockdown Register specifies which sectors in the main memory are currently unlocked or have

been permanently locked down. The Sector Lockdown Register is a read-only register and contains 64 bytes of data

which correspond to Sectors 0 through 63. To read the Sector Lockdown Register, an opcode of 35h must be clocked

into the device followed by three dummy bytes. After the last bit of the opcode and dummy bytes have been clocked in,

the data for the contents of the Sector Lockdown Register will be clocked out on the SO pin. The first byte (byte

location 0) corresponds to Sector 0 (0a and 0b), the second byte corresponds to Sector 1, and the last byte (byte location

63) corresponds to Sector 63. After the last byte of the Sector Lockdown Register has been read, additional pulses on

the SCK pin will result in undefined data being output on the SO pin.

Deasserting the CS pin will terminate the Read Sector Lockdown Register operation and put the SO pin into a

high-impedance state. Table 7-2 details the format the Sector Lockdown Register.

Table 7-2.

Sector Lockdown Register

Table 7-3.

Sector 0 (0a and 0b) Sector Lockdown Register Byte Value

Table 7-4.

Read Sector Lockdown Register Command

3Dh

2Ah

7Fh

30h

Address

byte

Address

byte

Address

byte

Each transition represents eight bits

Sector Number

0 (0a, 0b)

1 to 63

Locked

See Table 7-3

FFh

Unlocked

00h

Bit 7:6

Bit 5:4

Bit 3:2

Bit 1:0

Data

Value

Sector 0a

(Page 0-7)

Sector 0b

(Page 8-127)

N/A

Sectors 0a and 0b Unlocked

00h

Sector 0a Locked

C0h

Sector 0b Locked

30h

Sectors 0a and 0b Locked

F0h

Command

Byte 1

Byte 2

Byte 3

Byte 4

Read Sector Lockdown Register

35h

XXh

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