AK8963C Datasheet, PDF (14/38 Pages) Asahi Kasei Microsystems – 3-axis Electronic Compass

6.4. Description of Each Operation Mode
[AK8963]
6.4.1. Power-down Mode
Power to almost all internal circuits is turned off. All registers are accessible in power-down mode. However,
fuse ROM data cannot be read correctly. Data stored in read/write registers are remained. They can be reset by
soft reset.
6.4.2. Single Measurement Mode
When single measurement mode (MODE[3:0]=“0001”) is set, sensor is measured, and after sensor
measurement and signal processing is finished, measurement data is stored to measurement data registers
(HXL to HZH), then AK8963 transits to power-down mode automatically. On transition to power-down mode,
MODE[3:0] turnes to “0000”. At the same time, DRDY bit in ST1 register turnes to “1”. This is called “Data
Ready”. When any of measurement data register (HXL to HZH) or ST2 register is read, DRDY bit turnes to
“0”. It remains “1” on transition from Power-down mode to another mode. DRDY pin is in the same state as
DRDY bit. (Refer to Figure 6.2.)
When sensor is measuring (Measurement period), measurement data registers (HXL ~ HZH) keep the
previous data. Therefore, it is possible to read out data even in measurement period. Data read out in
measurement period are previous data. (Refer to Figure 6.3.)
Operation Mode: Single measuremnet
Power-down
(1)
(2)
(3)
Measurement period
Measurement Data Register
Last Data
Measurement Data (1)
Data(2)
Data(3)
DRDY
Data read
Data(1)
Data(3)
Register Write MODE[3:0]="0001"
MODE[3:0]="0001" MODE[3:0]="0001"
Figure 6.2 Single measurement mode: when data is read out of measurement period
Operation Mode: Single measuremnet
Power-down
(1)
(2)
(3)
Measurement period
Measurement Data Register
Last Data
Measurement Data (1)
Data(2)
Data(3)
DRDY
Data read
Data(1)
Register Write MODE[3:0]="0001"
MODE[3:0]="0001" MODE[3:0]="0001"
Figure 6.3 Single measurement mode: when data read started during measurement period
MS1356-E-02
- 14 -
2013/10