LE24CB642MC

No.2090-9/14

6-3. Acknowledge polling

Acknowledge polling is used to find out when the EEPROM internal write operation is completed. When the stop

condition is received and the EEPROM starts rewriting, all operations are prohibited, and no response can be given to

the signals sent by the master device. Therefore, in order to find out when the EEPROM internal write operation is

completed, the start condition, device address and write command code are sent from the master device to the

EEPROM (slave device), and the response of the slave device is detected.

In other words, if the slave device does not send the acknowledge signal, it means that the internal write operation is

in progress; conversely, if it does send the acknowledge signal, it means that the internal write operation has been

completed.

When codes are sent by the master device during acknowledge polling, if a write or random read is to be performed

next, the write command "0" is executed. If a current read or sequential read is to be performed next, the read

command "1" is executed. After the write command "0" is executed and ACK="L" is confirmed, the start

condition/stop condition is entered to cancel the command and change to standby mode.

SDA

1 0 1 0

W

R/W

NO ACK

1 0 1 0

W

R/W

NO ACK

1 0 1 0

W

R/W

ACK

Write timing

Writing end

Write timing

S1

S2

S0

S1

S2

S0

S1

S2

S0