AK9752 Datasheet, PDF (19/36 Pages) Asahi Kasei Microsystems – Ultra-small IR sensor IC with IC

[AK9752]
R/W= 0
SDA
S ^Slave
Address
Register
Address(n) ^{DATA(n) DATA(n+1)}
DATA(n+x) ^P
Figure 11.7. Write Operation
11.1.6. Read Command
When the R/W bit is set to “1”, the AK9752 executes a read operation. When the AK9752 transmits data
from the specified address, the master device generates an Acknowledge instead of a Stop Condition
and the next address data can be read out.
This automatic address increment works for the registers which store ST1, interrupt factor information,
IR measurement data, Temperature Sensor measurement data, ST2(04H~0AH) and thresholds of IR,
thresholds of Temperature Sensor, interrupt factor setting, cut-off frequency of digital filter, and operation
mode(0BH~15H).
The address counter returns to address 04H after reaching address 0AH.
The address counter returns to address 0BH after reaching address 15H.
The AK9752 supports both current address read and random address read.
(1) Current Address Read
The AK9752 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 is “n”, the data of address “n+1” is read
out by the current address read instruction.
The AK9752 will generate an Acknowledge after receiving the slave address for a read command (R/W
bit = “1”) in the current address read operation. Then the AK9752 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 AK9752 generates a Stop Condition instead of an Acknowledge after transmitting the one byte
data, a read out operation is terminated.
R/W= “1”
SDA S ^Slave
Address
DATA(n) DATA(n+1)
DATA(n+2)
DATA(n+x) ^P
Figure 11.8. Current Address Read
(2) Random Read
Data from an arbitrary address can be read out by a random read operation. A random read requires the
input of a dummy write instruction before the input of the slave address of a read instruction (R/W bit =
“1”). To execute a random read, first generate a Start Condition, then input the slave address for a write
instruction (R/W bit = “0”) and a read address, sequentially.
After the AK9752 generates an Acknowledge in response to this address input, generate a Start
Condition and the slave address for a read instruction (R/W bit = “1”) again. The AK9752 generates an
Acknowledge in response to the input of this slave address. Next, the AK9752 output the data at the
specified address, then increments the internal address counter by one.
When a Stop Condition from the master device is generated in generated instead of an Acknowledge
after the AK9752 outputs data, Read operation stops.
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