X24022
Stop Condition
All communications must be terminated by a stop con-
dition, which is a LOW to HIGH transition of SDA when
SCL is HIGH. The stop condition is also used by the
X24022 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.
Figure 2. Definition of Start and Stop
The X24022 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 X24022 will respond with an acknowledge
after the receipt of each subsequent eight bit word.
In the read mode the X24022 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 X24022
will continue to transmit data. If an acknowledge is not
detected, the X24022 will terminate further data trans-
missions. The master must then issue a stop condition
to return the X24022 to the standby power mode and
place the device into a known state.
SCL
SDA
START BIT
STOP BIT
3848 FHD F07
Figure 3. Acknowledge Response From Receiver
SCL FROM
MASTER
1
8
9
DATA
OUTPUT
FROM
TRANSMITTER
DATA
OUTPUT
FROM
RECEIVER
START
ACKNOWLEDGE
3848 FHD F08
4
XICOR [ XICOR INC. ]
