AK9720 Datasheet, PDF (22/31 Pages) Asahi Kasei Microsystems – IR Sensor Module with I2C I/F

[AK9720]
Serial Interface
The I²C bus interface of the AK9720 supports Standard Mode (Max. 100kHz) and High
Speed Mode (Max.400 kHz).
1. Data Transfer
Initially, the start condition should be input to access the AK9720 through the bus. Next,
send a one byte slave address, which includes the device address. The the AK9720
compares the slave address, and if these addresses match, the AK9720 generates an
acknowledge signal and executes a Read/Write instruction. The stop condition should be
input after executing an instruction.
1.1 Changing state of the SDA line
The SDA line state should be changed only while the SCL line is “Low”. The SDA line
state must be maintained while the SCL line is “High”.
The SDA line state can be changed while the SCL line is “High”, only when a Start
Condition or a Stop Condition is input.
SCL
SDA
Constant
Changing
State
Enable
Fig.1. Changing state of SDA line
1.2 Start/Stop Conditions
A Start condition is generated when the SDA line state is changed from “High” to “Low”
while the SCL line is “High”. All instructions start from a Start condition.
A Stop condition is generated when the SDA line state is changed from “Low” to “High”
while the SCL line is “High”. All instructions end after a Stop condition.
SCL
SDA
Start Condition
Stop Condition
Fig.2. Start/Stop Conditions
Rev.02
AKM Confidential
- 22 -
2012/11