M95256-R datasheet(22/51 Pages) STMICROELECTRONICS

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6.7

Read Identification page (available only in M95256-D devices)

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

Read-only mode.

This page is read with the Read Identification page instruction (see Table 4. Instruction set). The Chip select

signal (S) is first driven low, the bits of the instruction byte and address bytes are then shifted in, on Serial data

input (D). Address bit A10 must be 0, upper address bits are Don't care, and the data byte pointed to by the lower

address bits [A5:A0] is shifted out on Serial data output (Q). If Chip select (S) continues to be low, the internal

address register is automatically incremented, and the byte of data at the new address is shifted out.

The number of bytes to read in the ID page must not exceed the page boundary, otherwise unexpected data are

read (for instance when reading the ID page from location 24d, the number of bytes must be lower than or equal

to 40d, as the ID page boundary is 64 bytes).

The read cycle is terminated by driving Chip select (S) high. The rising edge of the Chip select (S) signal can

occur at any time during the cycle. The first byte addressed can be any byte within any page.

The instruction is not accepted, and is not executed, if a write cycle is currently in progress.

Figure 15. Read Identification page sequence

3 4 5 6 7 8 9 10

20 21 22 23 24 25 26 27

14 13

28 29 30

High impedance

Data Out 1

Instruction

16-bit address

MSB

Data Out 2

M95256-W M95256-R M95256-DF

Read Identification page (available only in M95256-D devices)

DS4712 - Rev 22

page 22/51

M95256-R 데이터시트(PDF) 22 Page - STMicroelectronics