PNI RM3000 Sensor Suites - Manual (Page 34)

PNI Sensor Corporation Doc #1015673 r08
RM3000 & RM2000 Sensor Suite User Manual – July 2012 Page 34 of 41
5.3.3 MAM Axes Select Byte
The MAM Axes Select Byte establishes which axes are to be measured and 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 Measured AAX1 AAX0
X, Y, and Z 0 0
X and Y 0 1
X only 1 0
No axis measured 1 1
5.3.4 Making a Multi-Axis Measurement
The steps to make a multi-axis sensor 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.
Initiate a sensor measurement by sending 82
H
(MAM Command Byte to write to
the Mode Register) followed by 01
H
(Mode Register Word to initiate
measurement) on the MOSI pin. 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.