X24C02

4

Stop Condition

All communications must be terminated by a stop condition,

which is a LOW to HIGH transition of SDA when SCL is

HIGH. The stop condition is also used by the X24C02 to

place the device in the standby power mode after a read

sequence. A stop condition can only be issued after the

transmitting device has released the

bus.

Acknowledge

Acknowledge is a software convention used to indicate

successful data transfer. The transmitting device, either

master or slave, will release the bus after transmitting

eight bits. During the ninth clock cycle the receiver will

pull the SDA line LOW to acknowledge that it received the

eight bits of data. Refer to Figure 3.

The X24C02 will respond with an acknowledge after

recognition of a start condition and its slave address. If

both the device and a write operation have been

selected, the X24C02 will respond with an acknowledge

after the receipt of each subsequent eight bit word.

In the read mode the X24C02 will transmit eight bits of data,

release the SDA line and monitor the line for an

acknowledge. If an acknowledge is detected and no stop

condition is generated by the master, the X24C02

will continue to transmit data. If an acknowledge is not

detected, the X24C02 will terminate further data trans-

missions. The master must then issue a stop condition to

return the X24C02 to the standby power mode and

place the device into a known state.

Figure 2. Definition of Start and Stop

SCL

SDA

START BIT

STOP BIT

Figure 3. Acknowledge Response From Receiver

SCL FROM

MASTER

DATA

OUTPUT

FROM

TRANSMITTER

1

8

9

DATA

OUTPUT

FROM

RECEIVER

START

ACKNOWLEDGE

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