AN2440

Power loss and data corruption

Doc ID 023074 Rev 4

9/13

4

Power loss and data corruption

4.1

Updating data

addressed data bytes are accessed and, in case of a supply voltage drop during the internal

Figure 8.

Data corruption due to power-down during a write process

In EEPROMs with embedded ECCx4, when writing one (or more) byte inside a word, the

might be incorrectly written but the data corruption is limited to these addressed data

bytes(d). Figure 8 shows two examples of data corruption in an EEPROM with embedded

ECCx4:

●

Case 1 describes data corruption when the data to update belongs to the same word.

●

Case 2 describes data corruption when the data to update belongs to two different

words.

d.

This is not tested in production but only characterized during the product qualification.

ai13478

Byte0 Byte1 Byte2 Byte3 ECC1

Byte4 Byte5 Byte6 Byte7 ECC2

Memory array

Power-down during a Write cycle

Byte4 Byte5 Byte6 Byte7 ECC2

One word lost

4 bytes & ECC wrong

Correct data

Three new data bytes to be written

CASE 1

CASE 2

Byte8 Byte9 Byte10 Byte11 ECC1

Byte12 Byte13 Byte14 Byte15 ECC2

Power-down during a Write cycle

Two words lost

8 bytes & ECC wrong

Three new data bytes to be written