X24012

4

Stop Condition

All communications must be terminated by a stop condi-

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

is HIGH. The stop condition is also used by the X24012 to

place the device into 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 transfers. The transmitting device 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 X24012 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 X24012 will respond with an acknowledge

after the receipt of each subsequent eight bit word.

In the read mode the X24012 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 X24012

will continue to transmit data. If an acknowledge is not

detected, the X24012 will terminate further data trans-

missions. The master must then issue a stop condition to

return the X24012 to the standby power mode and

place the device into a known state

.

Figure 3. Acknowledge Response From Receiver

3847 FHD F07

SCL FROM

MASTER

DATA

OUTPUT

FROM

TRANSMITTER

1

8

9

DATA

OUTPUT

FROM

RECEIVER

START

ACKNOWLEDGE