M24LR64-R memory organization

AN3171

10/14

Doc ID 17229 Rev 1

Figure 6.

3.2

System memory seen from the I²C bus (E2=1)

The M24LR64-R device offers an additional EEPROM memory area named the system

memory (see Figure 4: M24LR64-R’s user and system memories). The system memory can

only be accessed in read or/and write mode through the I²C bus by setting the E2 bit to 1 in

the device select byte.

3.2.1

M24LR64-R’s RF block security status

The 64 bytes in the system memory store the RF block security status value of each RF

sector (1 byte for 1 sector).

This RF block security status can be read from the I²C bus in order to verify the protection of

the user memory, when accessed from the RF channel.

The data in the RF block security status can be erased or modified from the I²C bus only if

the I²C password has been presented successfully.

ai15126

Device select

code

Password

address 09h

Password

address 00h

New password

[31:24]

Ack

R/W

Ack

Ack

Ack

Device select code = 1010 1 E1 E0

New password

[23:16]

New password

[15:8]

New password

[7:0]

Ack

Ack

Ack

Validation

code 07h

Ack

New password

[31:24]

Ack

New password

[23:16]

New password

[15:8]

New password

[7:0]

Ack

Ack

Ack

Table 3.

RF block security status

Bits [31:24]

Bits [23:16]

Bits [15:8]

Bits [7:0]

E2 = 1

0

SSS 3

SSS 2

SSS 1

SSS 0

E2 = 1

4

SSS 7

SSS 6

SSS 5

SSS 4

E2 = 1

8

SSS 11

SSS 10

SSS 9

SSS 8

E2 = 1

12

SSS 15

SSS 14

SSS 13

SSS 12

E2 = 1

16

SSS 19

SSS 18

SSS 17

SSS 16

E2 = 1

20

SSS 23

SSS 22

SSS 21

SSS 20

E2 = 1

24

SSS 27

SSS 26

SSS 25

SSS 24

E2 = 1

28

SSS 31

SSS 30

SSS 29

SSS 28

E2 = 1

32

SSS 35

SSS 34

SSS 33

SSS 32

E2 = 1

36

SSS 39

SSS 38

SSS 37

SSS 36

E2 = 1

40

SSS 43

SSS 42

SSS 41

SSS 40