X45620 Datasheet, PDF (13/20 Pages) Intersil Corporation – Dual Voltage Monitor with Integrated System Battery Switch and EEPROM

Figure 7. Data Validity
X45620
SCL
SDA
Data Stable Data
Change
Figure 8. Definition of Start and Stop
SCL
SDA
Start Bit
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 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 indi-
cate successful data transfer. The transmitting device,
either master or slave, will release the bus after trans-
mitting 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 9.
Figure 9. Acknowledge Response From Receiver
SCL from
Master
1
Data Output
from Transmitter
Stop Bit
The device 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 device will respond with an acknowledge
after the receipt of each subsequent 8-bit word.
In the read mode the device 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 device
will continue to transmit data. If an acknowledge is not
detected, the device will terminate further data trans-
missions. The master must then issue a stop condition
to return the device to the standby power mode and
place the device into a known state.
8
9
Data Output
fromReceiver
Start
Acknowledge
13
FN8250.0
July 29, 2005