AN3171

M24LR64-R memory organization

Doc ID 17229 Rev 1

9/14

3.1.3

Read

The M24C64 and M24LR64-R are read identically (from the I²C bus).

3.1.4

I²C Present Password

It is a command specific to the M24LR64-R. Figure 5 shows the command sequence.

To write data to a locked sector or the system memory, the system has to present the correct

password. This is done using the I²C Present Password command. With this command, you

can:

●

In User memory (see Figure 4: M24LR64-R’s user and system memories):

–

write data to the write-protected sector(s)

●

In System memory (see Figure 4: M24LR64-R’s user and system memories):

–

modify each I²C_Write_Lock bit

–

modify each RF block Security bit

–

read the I²C password

The password is 32 bits long.

Figure 5.

3.1.5

I²C Write Password

This command also is specific to the M24LR64-R. Figure 6 shows the command sequence.

The I²C Write Password command is used to change the I²C password. It has to be

preceded by a correct I²C Present Password sequence, otherwise it is not executed.

ai15125b

Device select

code

Password

address 09h

Password

address 00h

Password

[31:24]

Ack

R/W

Ack

Ack

Ack

Device select code = 1010 1 E1 E0

Password

[23:16]

Password

[15:8]

Password

[7:0]

Ack

Ack

Ack

Validation

code 09h

Ack

Password

[31:24]

Ack

Password

[23:16]

Password

[15:8]

Password

[7:0]

Ack

Ack

Ack