X9470 Datasheet, PDF (21/25 Pages) Xicor Inc. – RF Power Amplifier (PA) Bias Controller

Preliminary Information
X9470
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. See Figure 9.
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 10.
Figure 9. Valid Start and Stop Conditions
The device will respond with an acknowledge after rec-
ognition of a start condition and if the correct Device
Identifier and Select bits are contained in the Slave
Address Byte. If a write operation is selected, the
device will respond with an acknowledge after the
receipt of each subsequent eight bit word. The device
will acknowledge all incoming data and address bytes,
except for:
– The Slave Address Byte when the Device Identifier
and/or Select bits are incorrect
– The 2nd Data Byte of a Status Register Write Opera-
tion (only 1 data byte is allowed)
SCL
SDA
Start
Figure 10. Acknowledge Response From Receiver
SCL from
Master
1
Data Output
from Transmitter
Data Output
from Receiver
Start
Figure 11. Valid Data Changes on the SDA Bus
SCL
Stop
8
9
Acknowledge
SDA
Data Stable
Data Change
Data Stable
REV 11.16 3/20/03
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