AK09918 Datasheet, PDF (14/30 Pages) Asahi Kasei Microsystems – 3-axis Electronic Compass

[AK09918]
Although Nth data is read out when it is performed during (N+1)th measurement period, (N+1)th data is obtained by
reading out again before completion of (N+2)th measurement.
(N-1)th Nth
(N+1)th
(N+2)th
PD Measurement
PD
Measurement
PD
Measurement
PD
Internal Buffer
(N-1)th
Nth
(N+1)th
(N+2)th
Measurement Data Register
(N-1)th
Nth
Data register is protected
because data is being read
(N+1)th
DRDY
DRDY changes to "1"
because read-out becomes possible.
DOR
Data read
ST1 Data(N)
ST2
ST1 Data(N+1)
Figure 9.9. Read-out is performed before completion of the next measurement after data protection.
9.4.3.5. End Operation
Set Power-down mode (MODE[4:0] bits = “00000”) to end Continuous measurement mode.
9.4.3.6. Magnetic Sensor Overflow
AK09918 has the limitation for measurement range that the sum of absolute values of each axis should be
smaller than 4912 μT. (Note 8)
|X|+|Y|+|Z| < 4912 μT
When the magnetic field exceeded this limitation, data stored at measurement data are not correct. This is
called Magnetic Sensor Overflow.
When magnetic sensor overflow occurs, HOFL bit turns to “1”.
When measurement data register (HXL to HZH) is updated, HOFL bit is updated.
(Note 8) BRG: 0.15μT/LSB
016014242-E-00
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2016/11