M24LR04E-R datasheet(29/142 Pages) STMICROELECTRONICS

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M24LR04E-R

System memory area

Doc ID 022208 Rev 5

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4.3.4

Configuration byte access in I²C and RF modes

In I²C mode, read and write accesses to the non-volatile Configuration byte are always

allowed. To access the Configuration byte, the device select code used for any I²C

command must have the E2 Chip enable address at 1.

The dedicated commands to access the Configuration byte in RF mode are:

●

Read configuration byte command (ReadCfg):

The ReadCfg command is used to read the eight bits of the Configuration byte.

●

Write energy harvesting configuration command (WriteEHCfg):

The WriteEHCfg command is used to write the EH_mode, EH_cfg1 and EH_cfg0 bits into

the Configuration byte.

●

Write RF WIP/BUSY pin configuration command (WriteDOCfg):

The WriteDOCfg command is used to write the RF WIP/BUSY bit into the Configuration

byte.

After any write access to the Configuration byte, the new configuration is automatically

applied.

4.3.5

Control register access in I²C or RF mode

In I²C mode, read and write accesses to the volatile Control register are always allowed. To

access the Control register, the device select code used for any I²C command must have the

E2 Chip enable address at 1.

The dedicated commands to access the Control register in RF mode are:

●

Check energy harvesting enable bit command (CheckEHEn):

The CheckEHEn command is used to read the eight bits of the Control register. When it is

run, the FIELD_ON bit is always read at 1.

●

Set/reset energy harvesting enable bit command (SetRstEHEn):

The SetRstEHEn command is used to set or reset the value of the EH_enable bit into the

Control register.

4.4

ISO 15693 system parameters

The M24LR04E-R provides the system area required by the ISO 15693 RF protocol, as

shown in Table 17.

The first 32-bit block starting from I2C address 2304 stores the I2C password. This password

is used to activate/deactivate the write protection of the protected sector in I2C mode. At

power-on, all user memory sectors protected by the I2C_Write_Lock bits can be read but

cannot be modified. To remove the write protection, it is necessary to use the I2C present

password described in Figure 12. When the password is correctly presented — that is, when

all the presented bits correspond to the stored ones — it is also possible to modify the I2C

password using the I2C write password command described in Figure 13.

The next three 32-bit blocks store the three RF passwords. These passwords are neither

read- nor write- accessible in the I2C mode.

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