M24C64 datasheet(17/38 Pages) STMICROELECTRONICS

17 / 38 page

M24128, M24C64, M24C32

Device operation

17/38

Figure 8.

Write mode sequences with WC = 0 (data write enabled)

4.9

ECC (error correction code) and Write cycling

The M24128-BFMB6 and M24C64-FMB6 salestypes offer an ECC (error correction code)

logic which compares each 4-byte word with its six associated EEPROM ECC bits. As a

result, if a single bit out of 4 bytes of data happens to be erroneous during a read operation,

the ECC detects it and replaces it by the correct value. The read reliability is therefore much

improved by the use of this feature.

Note however that even if a single byte has to be written, 4 bytes are internally modified

(plus the ECC word), that is, the addressed byte is cycled together with the three other bytes

making up the word. It is therefore recommended to write by packets of 4 bytes in order to

benefit from the larger amount of write cycles.

All M24C32, M24C64 and M24128 devices are qualified at 1 million (1 000 000) write

cycles; the M24128-BFMB6 and M24C64-FMB6 are qualified (at 1 million write cycles),

using a cycling routine that writes to the device by multiples of 4-byte words.

Byte Write

Dev Select

Byte address

Data in

Page Write

Dev Select

Byte address

Data in 1

Data in 2

AI01106d

Page Write

(cont'd)

WC (cont'd)

Data in N

ACK

R/W

ACK

R/W

ACK

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