SLx 24C01/02/P

Semiconductor Group

18

1998-07-27

7

Page Protection Mode

TM

Each page (8 bytes) in the Data Memory can be protected against unintended data

changes by an associated protection bit. The protection bit memory consists of an

additional EEPROM of 16/32 bits (figure 14).

Data in the Data Memory can be modified only if the assigned protection bit is erased

(logical state“1”). Afterwriting thedatabytes toapage, theprotectionis achievedby

writing the associated protection bit (logical state “0”). Further changes in the data in a

protected page is possible only after erasing the protection bit.

Figure 14

Data Page and Assigned Protection Memory

A special procedure to write or erase a protection bit guarantees proper activation or

deactivation respectively of page protection. For protection bit write or erase, all 8 data

bytes of the respective page have to be entered for a second time. The data then are

compared internally with the data to be protected, and in case of identity the protection

bit is written or erased respectively.

1

02 3

.

.

.

.

.

.

0

1

2

3

n

Page 0

Page 1

Page 2

Page 3

Page n

Byte

Bit

Data Memory Area

IED02141

567

4