6.6

Read identification page

Following a start condition the bus master sends a device select code with the RW bit (RW) set to '0'. The device

acknowledges this and waits for the address bytes where the identification page is located. The device responds

to each address byte with an acknowledge bit. The bits A6/A0 define the byte address inside the identification

page. Then, the bus master sends another start condition, and repeats the same device select code but with

the RW bit set to '1'. The device acknowledges this, and outputs the contents of the identification page. See in

Section 5.5 Device addressing (Table 5, Table 6 and Table 7) how to address the identification page.

The number of bytes to read in the ID page must not exceed the page boundary (e.g.: when reading the

identification page from location 10d, the number of bytes should be less than or equal to 54, as the ID page

boundary is 64 bytes). After the 64th byte of the identification page, there is no “roll-over” to the beginning of the

page.

To terminate the stream of data byte, the bus master must not acknowledge the byte, and must generate a stop

condition, as shown in Figure 12.

6.6.1

Read the lock status

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

command [identification page write instruction + one data byte] to the device. The device returns an acknowledge

bit if the identification page is unlocked, otherwise a no ACK bit if the identification page is locked.

Right after this, it is recommended to transmit to the device a start condition followed by a stop condition, so that:

•

Start: the truncated command is not executed because the start condition resets the device internal logic

•

Stop: the device is then set back into standby mode by the stop condition.

M24256X-F

Read identification page

DS12380 - Rev 2

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