SRI4K_11 datasheet(17/46 Pages) STMICROELECTRONICS

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SRI4K

Memory mapping

Doc 11605 Rev 5

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4.3

EEPROM area

The 121 blocks between addresses 7 and 127 are EEPROM blocks of 32 bits each (484

bytes in total). (See Figure 17 for a map of the area.) These blocks can be accessed using

the Read_block and Write_block commands. The Write_block command for the EEPROM

area always includes an auto-erase cycle prior to the write cycle.

Blocks 7 to 15 can be write-protected. Write access is controlled by the 8 bits of the

OTP_Lock_Reg located at block address 255 (see “OTP_Lock_Reg” for details). Once

protected, these blocks (7 to 15) cannot be unprotected.

Figure 17.

EEPROM (addresses 7 to 127)

4.4

System area

This area is used to modify the settings of the SRI4K. It contains 3 registers:

OTP_Lock_Reg, Fixed Chip_ID and ST Reserved. See Figure 18 for a map of this area.

A Write_block command in this area will not erase the previous contents. Selected bits can

thus be set from 1 to 0. All bits previously at 0 remain unchanged. Once all the 32 bits of a

block are at 0, the block is empty and cannot be updated any more.

Block

address

MSb

b31

32-bit block

b16 b15

b24 b23

b8 b7

LSb

Description

Lockable

EEPROM

User area

Ai07662c

...

User area

127

User area

EEPROM

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