M24256E-F datasheet(17/46 Pages) STMICROELECTRONICS

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6.2

Write identification page

The identification page (64 bytes) is an additional page which can be written and (later) permanently locked in

read-only mode. It is written by issuing the write identification page instruction. This instruction uses the same

protocol and format as page write (into memory array), except for the device select code and the address. See in

Section 5.5 Device addressing (Table 3, Table 4 and Table 5) how to address the identification page.

If the identification page is locked, the data bytes transferred during the write identification page instruction are not

acknowledged (noACK).

6.2.1

Lock identification page

The lock identification page instruction (lock ID) permanently locks the identification page in read-only mode. The

lock ID instruction is similar to byte write (into memory array) except for the device select code and the address.

See in Section 5.5 Device addressing (Table 3, Table 4 and Table 5) how to address the identification page.

The sent data byte must have the b1 bit equal to '1' (b1=1) and the others value of the bits b7 to b2 and b0 are

"Don't Care". The data byte have the following format: xxxx xx1x (where x = Don't Care)"

M24256E-F

Write identification page

DS12687 - Rev 2

page 17/46

M24256E-F Datenblatt(PDF) 17 Page - STMicroelectronics