Datasheet

Data Sheet ADT7320
Rev. 0 | Page 17 of 24
SERIAL INTERFACE
ADT7320
GND
SCLK
DOUT
DIN
CT
INT
V
DD
10kΩ10kΩ
PULL-UP
TO V
DD
0.1µF
MICROCONTROLLER
V
DD
CS
09012-014
Figure 14. Typical SPI Interface Connection
The ADT7320 has a 4-wire serial peripheral interface (SPI). The
interface has a data input pin (DIN) for writing data to the device, a
data output pin (DOUT) for reading data back from the device,
and a serial data clock pin (SCLK) for clocking data into and out of
the device. A chip select pin (
CS
) enables or disables the serial
interface.
CS
is required for correct operation of the interface.
Data is clocked out of the on the falling edge of SCLK,
and data is clocked into the device on the rising edge of SCLK.
ADT7320
SPI COMMAND BYTE
All data transactions on the bus begin with the master taking
CS
from high to low and sending out the command byte. The
command byte indicates to the whether the transaction
is a read or a write and provides the address of the register for the
data transfer. shows the command byte.
ADT7320
Tabl e 15
Table 15. Command Byte
C7 C6 C5 C4 C3 C2 C1 C0
0
R/W
Register address 0 0 0
Bit C7, Bit C2, Bit C1, and Bit C0 of the command byte must all be
set to 0 to successfully begin a bus transaction. The SPI interface
does not work correctly if a 1 is written into any of these bits.
Bit C6 is the read/
write
bit; 1 indicates a read, and 0 indicates
a write.
Bits[C5:C3] contain the target register address. One register can
be read from or written to per bus transaction.