AN3002

M24LRxx’s conditional memory access

Doc ID 15912 Rev 2

19/22

Figure 8.

RF multiple password memory access condition after password 2

presentation

Using the password 0 condition

The M24LRxx offers the possibility of permanently locking the RF read/write access rights of

a sector. The password 0 condition is applied by resetting (to ‘0’) the bits b4 and b3 in the

Sector security status byte (see Table 6: Password Control bits), and then by issuing the RF

Lock-sector Password command. The access rights defined by bits b2 and b1 (see Table 5:

Read / Write protection bit setting) are then applied in a permanent way. Indeed, since the

RF Present-sector Password command does not allow the use of Password 0, the sector

access rights once applied can no longer be modified.

4.1.3

access conditions described in Section 4.1.1: I2C access and Section 4.1.2: RF access.

The M24LRxx offers flexibility, allowing the sharing of data or restricting their access as

illustrated in Figure 9: M24LRxx RF and I2C access condition mix.

Access condition

M24LRxx user memory sectors

Password

Read and write

Password 2

Not accessible

Password 3

Not accessible

Password 1

Read and write

No password

Read and write

Password 2

Read only

Public area ROM

Application area 2

Application area 3

Application area 1

Public area EEPROM

Application area 2

ai17128

Not accessible

Non-accessible area