X96011 Datasheet, PDF (17/23 Pages) Intersil Corporation – Temperature Sensor with Look Up Table Memory and DAC

X96011
SERIAL INTERFACE
Serial Interface Conventions
The device supports a bidirectional bus oriented proto-
col. The protocol defines any device that sends data
onto the bus as a transmitter, and the receiving device
as the receiver. The device controlling the transfer is
called the master and the device being controlled is
called the slave. The master always initiates data
transfers, and provides the clock for both transmit and
receive operations. The X96011 operates as a slave in
all applications.
Serial Clock and Data
Data states on the SDA line can change only while
SCL is LOW. SDA state changes while SCL is HIGH
are reserved for indicating START and STOP condi-
tions. See Figure 10. On power-up of the X96011, the
SDA pin is in the input mode.
Serial Start Condition
All commands are preceded by the START condition,
which is a HIGH to LOW transition of SDA while SCL
is HIGH. The device continuously monitors the SDA
and SCL lines for the START condition and does not
respond to any command until this condition has been
met. See Figure 9.
Serial Stop Condition
All communications must be terminated by a STOP
condition, which is a LOW to HIGH transition of SDA
while 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.
Serial Acknowledge
An ACK (Acknowledge), is a software convention used
to indicate a successful data transfer. The transmitting
device, either master or slave, releases the bus after
transmitting eight bits. During the ninth clock cycle, the
receiver pulls the SDA line LOW to acknowledge the
reception of the eight bits of data. See Figure 11.
The device responds with an ACK after recognition of
a START condition followed by a valid Slave Address
byte. A valid Slave Address byte must contain the
Device Type Identifier 1010, and the Device Address
bits matching the logic state of pins A2, A1, and A0.
See Figure 13.
If a write operation is selected, the device responds
with an ACK after the receipt of each subsequent
eight-bit word.
In the read mode, the device transmits eight bits of
data, releases the SDA line, and then monitors the line
for an ACK. The device continues transmitting data if
an ACK is detected. The device terminates further
data transmissions if an ACK is not detected. The
master must then issue a STOP condition to place the
device into a known state.
The X96011 acknowledges all incoming data and
address bytes except: 1) The “Slave Address Byte”
when the “Device Identifier” or “Device Address” are
wrong; 2) All “Data Bytes” when the “WEL” bit is “0”,
with the exception of a “Data Byte” addresses to loca-
tion 86h; 3) “Data Bytes” following a “Data Byte”
addressed to locations 80h, 85h, or 86h.
17
FN8215.1
October 25, 2005