M24M02E-F datasheet(21/54 Pages) STMICROELECTRONICS

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6.2.5

Lock operation on identification page

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

Following a start condition the bus controller sends a device select code with the R/W bit (RW) set to 0. The

device acknowledges this, as shown in Figure 14, and waits for the address bytes where the identification page is

located. The device responds to each address byte with an acknowledge bit, and then waits for a specific data

byte value. See in Table 9, Table 10, and Table 11 how to address the identification page.

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

When the bus controller generates a stop condition immediately after the data byte ACK bit (in the tenth bit time

slot), the internal write cycle tW is triggered. A stop condition at any other time slot does not trigger the internal

write cycle.

During the internal write cycle, serial data (SDA) is disabled internally, and the device does not respond to any

requests (NO ACK).

If the identification page is already locked or hard write protected with WC line driven high, the write operation is

not executed and the accompanying data bytes are not acknowledged as shown in Figure 15.

Figure 14. Lock operation on identification page (unlocked or data write enabled)

Dev sel

Byte addr

Data in

ACK

Figure 15. Lock operation on identification page (already locked or data write inhibited)

Byte addr

Data in

ACK

NO ACK

R/W

Byte addr

Dev sel

M24M02E-F

Instructions

DS14157 - Rev 2

page 21/54

M24M02E-F 数据表(PDF) 21 Page - STMicroelectronics