4256BWP datasheet(17/41 Pages) STMICROELECTRONICS

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M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF

Instructions

Doc ID 6757 Rev 28

17/41

5.1.3

Write Identification Page (M24256-D only)

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 following differences:

●

Device type identifier = 1011b

●

MSB address bits A15/A6 are don't care except for address bit A10 which must be ‘0’.

LSB address bits A5/A0 define the byte address inside the Identification page.

If the Identification page is locked, the data bytes transferred during the Write Identification

Page instruction are not acknowledged (NoAck).

5.1.4

Lock Identification Page (M24256-D only)

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) with

the following specific conditions:

●

Device type identifier = 1011b

●

Address bit A10 must be ‘1’; all other address bits are don't care

●

The data byte must be equal to the binary value xxxx xx1x, where x is don't care

4256BWP Datasheet(PDF) 17 Page - STMicroelectronics