PNI RM3000-F Sensor Suite - Manual (Page 34)

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RM3000-f & RM2000-f Sensor Suite User Manual Page 34
5.3.3 MAM Axes Select Byte
The MAM Axes Select Byte establishes which axes are to be measured and initiates a
multi-axis measurement. It is defined as follows:
Bit # 7 6 5 4 3 2 1 0
Value 0 0 0 AAX1 AAX0 0 0 1
Table 5-3: MAM Axes Select Bits
Axes to be Measured AAX1 AAX0 Axes Select Byte
X, Y, and Z 0 0 0x01
X and Y 0 1 0x09
X only 1 0 0x11
No axis measured 1 1 0x19
5.3.4 Making a Multi-Axis Measurement
The steps to make an interrupt-driven multi-axis measurement are given below. The 3D
MagIC will return the result of a complete forward-reverse measurement of each sensor
in a 24-bit 2’s complement format (range: -8388608 to 8388607).
Start with SSN set HIGH, then set SSN to LOW.
Send 0x82 on the MOSI line. This is the MAM Command Byte that sets up the
3D MagIC to make a new measurement,
Send by 0x01 on the MOSI line. This is the Axes Select Byte which specifies that
a 3-axis measurement is to be taken. The 3D MagIC will now take the prescribed
measurements.
Return SSN to HIGH. This will not affect the measurement process, but will free
up the host to communicate with other devices and ensure the next Command
Byte sent to the 3D MagIC is interpreted properly.
A measurement is taken.
At the end of the measurement, the DRDY pin is set HIGH, indicating data is
ready, and the 3D MagIC is placed in Idle Mode.
When the host is ready to read the measured values, set SSN to LOW. If SSN
already is LOW, then toggle SSN from LOW to HIGH to LOW.