Datasheet

ADT7316/ADT7317/ADT7318
Rev. B | Page 39 of 44
D7
D6
D5
D4
D3
D2
D1
X
X
X
X
X
X
X
D0
X
CS
SCLK
DIN
DOUT
START
READ COMMAND
DATA BYTE 1
18
1
8
X
XX
X
X
X
X
D6
D5
D4
D3
D2
D1
D0
XD7
STOP
02661-056
Figure 56. SPI —Reading a Single Byte of Data From a Selected Register
D7
D6
D5
D4
D3
D2
D1
X
X
XX
XX X
D0
X
CS
SCLK
DIN
DOUT
START
READ COMMAND
DATA BYTE 1
181
8
X
XX
X
X
X
XD6
D5
D4
D3
D2
D1
D0
X
D7
CS (CONTINUED)
SCLK (CONTINUED)
DIN (CONTINUED)
DOUT (CONTINUED)
STOP
DATA BYTE 2
X
X
X
X
X
X
X
X
1
8
D7
D6
D5
D4 D3
D2
D1 D0
02661-057
Figure 57. SPI—Reading Two Bytes of Data From Two Sequential Registers
CS
SPI READ OPERATION WRITE OPERATION
02661-058
Figure 58. SPI—Correct Use of
CS
During SPI Communication
Read Operation
Figure 56 and Figure 57 show the timing diagrams necessary
to accomplish correct read operations. To read back from a
register, first write to the address pointer register with the
address of the register to read from, as shown in
Figure 53.
Figure 56 shows the procedure for reading back a single byte
o
f data. The read command is first sent to the part during the
first eight clock cycles. As the read command is being sent,
irrelevant data is output onto the DOUT line. During the
following eight clock cycles, the data contained in the register
selected by the address pointer register is output onto the
DOUT line. Data is output onto the DOUT line on the falling
edge of SCLK.
Figure 57 shows the procedure when reading
da
ta from two sequential registers. Multiple data reads are
possible in SPI interface mode as the address pointer register is
auto-incremental. The address pointer register auto-increments
from Address 0x00 to Address 0x3F and loops back to start all
over again at Address 0x00 when it reaches Address 0x3F.