X24C01A

3

Figure 1. Data Validity

Figure 2. Definition of Start and Stop

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 X24C01A

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 X24C01A 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 se-

lected, the X24C01A will respond with an acknowledge

after the receipt of each subsequent eight bit word.

In the read mode the X24C01A 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 X24C01A

will continue to transmit data. If an acknowledge is not

detected, the X24C01A will terminate further data trans-

missions. The master must then issue a stop condition

to return the X24C01A to the standby power mode and

place the device into a known state.

Figure 3. Acknowledge Response From Receiver

SCL

SDA

DATA STABLE

DATA

CHANGE

3841 FHD F05

3841 FHD F06

3841 FHD F07

SCL FROM

MASTER

DATA

OUTPUT

FROM

TRANSMITTER

1

89

DATA

OUTPUT

FROM

RECEIVER

START

ACKNOWLEDGE

SCL

SDA

START BIT

STOP BIT