AK09918C Datasheet, PDF (15/30 Pages) Asahi Kasei Microsystems – 3-axis Electronic Compass

[AK09918]
9.4.4. Self-test Mode
Self-test mode is used to check if the magnetic sensor is working normally.
When Self-test mode (MODE[4:0] bits = “10000”) is set, magnetic field is generated by the internal
magnetic source and magnetic sensor is measured. Measurement data is stored to measurement data registers
(HXL to HZH), then AK09918 transits to Power-down mode automatically.
Data read sequence and functions of read-only registers in Self-test mode is the same as Single measurement
mode.
9.4.4.1. Self-test Sequence
(1) Set Power-down mode. (MODE[4:0] bits = “00000”)
(2) Set Self-test mode. (MODE[4:0] bits = “10000”)
(3) Check Data Ready or not by polling DRDY bit of ST1 register.
When Data Ready, proceed to the next step.
(4) Read measurement data. (HXL to HZH)
9.4.4.2. Self-test Judgment
When measurement data read by the above sequence is in the range of following table, AK09918 is working
normally.
Criteria
HX[15:0] bits
-200 ≤ HX ≤ 200
HY[15:0] bits
-200 ≤ HY ≤ 200
HZ[15:0] bits
-1000 ≤ HZ ≤ -150
016014242-E-00
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2016/11