AK09915 Datasheet, PDF (16/42 Pages) Asahi Kasei Microsystems – 3-axis Electronic Compass

[AK09915]
9.4.3. Continuous Measurement Mode 1, 2, 3, 4, 5 and 6
When Continuous measurement modes (1 to 6) are set, magnetic sensor measurement is started periodically at
10 Hz, 20 Hz, 50 Hz, 100 Hz, 200 Hz and 1Hz respectively. After magnetic sensor measurement and signal
processing is finished, measurement magnetic data is stored to measurement data registers (HXL to HZH) and
all circuits except for the minimum circuit required for counting cycle length are turned off (PD). When the
next measurement timing comes, AK09915 wakes up automatically from PD and starts measurement again.
Continuous measurement mode ends when Power-down mode (MODE[4:0] bits = “00000”) is set. It repeats
measurement until Power-down mode is set.
When Continuous measurement modes (1 to 6) are set again while AK09915 is already in Continuous
measurement mode, a new measurement starts. ST1, ST2 and measurement data registers (HXL to TMPS) will
not be initialized by this.
Table 9.2 Continuous measurement modes
Operation mode
Register setting Measurement frequency
(MODE[4:0] bits)
[Hz]
Continuous measurement mode 1
00010
10
Continuous measurement mode 2
00100
20
Continuous measurement mode 3
00110
50
Continuous measurement mode 4
01000
100
Continuous measurement mode 5
01010
200
Continuous measurement mode 6
01100
1
(N-1)th
Nth
(N+1)th
PD
Measurement
PD
Measurement
PD
10Hz,20Hz,50Hz,100Hz,200Hz and 1Hz
Figure 9.4 Continuous measurement mode
9.4.3.1. Data Ready
When measurement data is stored and ready to be read, DRDY bit in ST1 register turns to “1”. This is called
“Data Ready”. DRDY pin is in the same state as DRDY bit. When measurement is performed correctly,
AK09915 becomes Data Ready on transition to PD after measurement.
015006484-E-02
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2016/7