AK9720 Datasheet, PDF (25/31 Pages) Asahi Kasei Microsystems – IR Sensor Module with I2C I/F

[AK9720]
master device.
MSB
LSB
D7 D6 D5 D4 D3 D2 D1 D0
Fig.6. Control data
Two or more bytes can be written to the AK9720 at once.
The AK9720 generates an Acknowledge and receives the next data after receiving the
third byte (Control Data). When the following data is transmitted without a Stop condition,
after transmitting one byte, the internal address counter is automatically incremented, and
data is written in the next address.
The automatic increment function works in the address from 00H to 14H and the address
from 15H to 18H. When the start address is “00H”, the address is repeatedly incremented
as follows: “00H -> 01H -> ... -> 14H -> 00H -> 01H ...”. When the start address is “15H”,
the address is repeatedly incremented as follows: “15H -> 16H -> ... -> 18H -> 15H ->
16H ...”.
S
T
S
A
R
R/W=0
T
O
T
P
SDA
S ^Slave
Address
Register
Address(n)
A
C
K
Data(n)
A
C
K
Data(n+1)
A
A
C
C
K
K
Data(n+x)
P
A
A
C
C
K
K
Fig.7. WRITE Operation
2. READ Instruction
When the R/W bit is set to “1”, the AK9720 executes a READ Operation.
When the AK9720 transmits the data from the specified address, and then the master
device generates an Acknowledge instead of a Stop condition, the next address data can
be read out.
The AK9720 supports both current address read and random address read.
The automatic increment function works in the address of 00H to 13H, and the address of
14H to 16H.
When the address 13H is read out, the next address returns to 00H.
When the address 16H is read out, the next address returns to 14H.
2.1 Current Address Read
The AK9720 has an integrated address counter. The data specified by the counter is read
out in the current address read operation. The internal address counter retains the next
address which is accessed at last.
For example, when the address which was accessed last was ”n”, the data of address
“n+1” is read out by the current address read instruction.
The AK9720 will generate an Acknowledge after receiving a Slave address for a Read
instruction (R/W bit =”1”) in the current address read operation. Then, the AK9720 will start
to transmit the data specified by the internal address counter at the next clock, and will
increment the internal address counter by one.
When the AK9720 generates a Stop condition instead of an Acknowledge after
transmitting the one byte data, a Read out operation is terminated.
Rev.02
AKM Confidential
- 25 -
2012/11