AK09918 Datasheet, PDF (11/30 Pages) Asahi Kasei Microsystems – 3-axis Electronic Compass

[AK09918]
9.4.3. Continuous Measurement Mode 1, 2, 3 and 4
When Continuous measurement mode 1 (MODE[4:0] bits = “00010”), 2 (MODE[4:0] bits = “00100”), 3
(MODE[4:0] bits = “00110”) or 4 (MODE[4:0] bits = “01000”) is set, magnetic sensor measurement is
started periodically at 10 Hz, 20 Hz, 50 Hz or 100 Hz 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, AK09918 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 mode 1 (MODE[4:0] bits = “00010”), 2 (MODE[4:0] bits = “00100”), 3
(MODE[4:0] bits = “00110”) or 4 (MODE[4:0] bits = “01000”) is set again while AK09918 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.
(N-1)th
Nth
(N+1)th
PD
Measurement
PD
Measurement
PD
10Hz,20Hz,50Hz or 100Hz
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”. When measurement is performed correctly, AK09918 becomes Data Ready on transition to
PD after measurement.
016014242-E-00
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2016/11