SRIX4K datasheet(17/50 Pages) STMICROELECTRONICS

17 / 50 page

SRIX4K

Memory mapping

17/50

Figure 16.

Count down example (binary format)

The counter with block address 6 controls the Reload command used to reset the resettable

OTP area (addresses 0 to 4). Bits b31 to b21 act as an 11-bit Reload counter; whenever one

of these 11 bits is updated, the SRIX4K detects the change and adds an Erase cycle to the

WRITE_BLOCK command for locations 0 to 4 (see Section 4.1: Resettable OTP area). The

Erase cycle remains active until a POWER-OFF or a SELECT command is issued. The

SRIX4K’s resettable OTP area can be reloaded up to 2,047 times (211-1).

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 Section 4.4.1: OTP_Lock_Reg for

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

ai07661

...1111111111111

...111111111111

...

11111111111

Initial data

1-unit decrement

b31

...

11111111111

...

111111111

0100

...111111111

1000

1-unit decrement

8-unit decrement

Increment not allowed

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