AK09912 Datasheet, PDF (24/42 Pages) HuaXinAn Electronics CO.,LTD – 3-axis Electronic Compass

[AK09912]
7.2. I²C Bus Interface
The I²C bus interface of AK09912 supports the Standard mode (100 kHz max.), the Fast mode (400 kHz max.) and
High-speed mode (Hs-mode, 2.5 MHz max.).
7.2.1. Data Transfer
To access AK09912 on the bus, generate a start condition first.
Next, transmit a one-byte slave address including a device address. At this time, AK09912 compares the slave address with
its own address. If these addresses match, AK09912 generates an acknowledgement, and then executes READ or WRITE
instruction. At the end of instruction execution, generate a stop condition.
7.2.1.1. Change of Data
A change of data on the SDA line must be made during “Low” period of the clock on the SCL line. When the clock signal
on the SCL line is “High”, the state of the SDA line must be stable. (Data on the SDA line can be changed only when the
clock signal on the SCL line is “Low”.)
During the SCL line is “High”, the state of data on the SDA line is changed only when a start condition or a stop condition
is generated.
SCL
SDA
DATA LINE
STABLE :
DATA VALID
CHANGE
OF DATA
ALLOWED
Figure 7.3 Data Change
7.2.1.2. Start/Stop Condition
If the SDA line is driven to “Low” from “High” when the SCL line is “High”, a start condition is generated. Every
instruction starts with a start condition.
If the SDA line is driven to “High” from “Low” when the SCL line is “High”, a stop condition is generated. Every
instruction stops with a stop condition.
SCL
SDA
START CONDITION
STOP CONDITION
Figure 7.4 Start and Stop Condition
MS1547-E-02
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