AK9753 Datasheet, PDF (27/50 Pages) Asahi Kasei Microsystems – IR Sensor IC with I2C I/F

[AK9753]
12.1.6. READ Command
When the R/W bit is set to “1”, the AK9753 executes a READ Operation. When the AK9753 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.
The AK9753 supports both current address read and random address read. The automatic increment
function works in the address of 05H to 10H.
When the address 10H is read out, the next address returns to 05H.
(1) Current Address Read
The AK9753 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 AK9753 will generate an Acknowledge after receiving a Slave address for a Read command (R/W
bit = “1”) in the current address read operation. Then the AK9753 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 AK9753 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 12.8. 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 a 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 AK9753 generates an Acknowledge in response to this address input, generate a start
condition and the slave address for a READ instruction (R/W)R/W bit = “1”) again. The AK9753
generates an Acknowledge in response to the input of this slave address. Next, the AK9753 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 AK9753 outputs data, Read operation stops.
R/W= “0”
R/W= “1”
SDA
S
Slave
Address
Register
Address(n)
S
Slave
Address
DATA(n) DATA(n+1)
DATA(n+x) _P
Figure 12.9. Random Read
017005237-E-00
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2017/04