M24256-DR datasheet(22/42 Pages) STMICROELECTRONICS

22 / 42 page

Device operation

M24256-BF, M24256-BR, M24256-BW, M24256-DR

22/42

Doc ID 6757 Rev 21

3.18

Read Identification Page status (locked/unlocked)

The locked/unlocked status of the Identification page can be checked by issuing a specific

truncated instruction consisting of the Identification Page Write instruction followed by one

data byte. The data byte will be acknowledged if the Identification page is unlocked, while it

will not be acknowledged if the Identification page is locked.

Once the acknowledge bit of this data byte is read, it is recommended to generate a Start

condition followed by a Stop condition, so that:

●

The instruction is truncated and not executed as the Start condition resets the device

internal logic.

●

The device is set to Standby mode by the Stop condition.

3.19

Acknowledge in Read mode

For all Read instructions, the device waits, after each byte read, for an acknowledgment

during the 9th bit time. If the bus master does not drive Serial Data (SDA) Low during this

time, the device terminates the data transfer and switches to its Standby mode.

M24256-DR Datasheet(PDF) 22 Page - STMicroelectronics