AT45DB011D_12 Datasheet, PDF(16/51 Page) List of Unclassifed Manufacturers

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AT45DB011D_12 Datasheet, PDF (16/51 Pages) List of Unclassifed Manufacturers – 1-megabit 2.7-volt Minimum DataFlash

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9.1.3

Read Sector Protection Register Command

To read the Sector Protection Register, the CS pin must first be asserted. Once the CS pin has

been asserted, an opcode of 32H and three dummy bytes must be clocked in via the SI pin. After

the last bit of the opcode and dummy bytes have been clocked in, any additional clock pulses on

the SCK pins will result in data for the content of the Sector Protection Register being output on

the SO pin. The first byte corresponds to sector 0 (0a, 0b), the second byte corresponds to sec-

tor 1, the third byte corresponds to sector 2, and the last byte (byte 4) corresponds to sector 3.

Once the last byte of the Sector Protection Register has been clocked out, any additional clock

pulses will result in undefined data being output on the SO pin. The CS must be deasserted to

terminate the Read Sector Protection Register operation and put the output into a high-imped-

ance state.

Table 9-6. Read Sector Protection Register Command

Command

Read Sector Protection Register

Note: xx = Dummy Byte

Byte 1

32H

Byte 2

xxH

Byte 3

xxH

Byte 4

xxH

Figure 9-4. Read Sector Protection Register

Opcode

Each transition

represents 8 bits

Data Byte

n+1

Data Byte

n+3

9.1.4

Various Aspects About the Sector Protection Register

The Sector Protection Register is subject to a limit of 10,000 erase/program cycles. Users are

encouraged to carefully evaluate the number of times the Sector Protection Register will be

modified during the course of the applicationsâ life cycle. If the application requires that the Sec-

tor Protection Register be modified more than the specified limit of 10,000 cycles because the

application needs to temporarily unprotect individual sectors (sector protection remains enabled

while the Sector Protection Register is reprogrammed), then the application will need to limit this

practice. Instead, a combination of temporarily unprotecting individual sectors along with dis-

abling sector protection completely will need to be implemented by the application to ensure that

the limit of 10,000 cycles is not exceeded.

16 AT45DB011D

3639JâDFLASHâ11/2012

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