PNI RM3100 Sensor Suite - Manual (Page 32)

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RM3100 & RM2100 Sensor Suite User Manual Page 31 of 45
To set the TMRC register, send the register address, 0x0B, followed by the desired
TMRC register value. To read the TMRC register, send 0x8B.
Note: The Cycle Count Registers establish the maximum data rate of the sensors. For instance,
if the cycle count is set to 200
D
, then the maximum 3-axis update rate is ~430 Hz. If TMRC is set
to 0x92, indicating an update rate of ~600 Hz, the rate established by the cycle count will override
the TMRC request, and the actual update rate will be ~430 Hz.
Table 5-4: CMM Update Rates
TMRC Value
(Hex)
Time Between
Readings
Update
Rate
92 ~1.7 ms ~600 Hz
93 ~3 ms ~300 Hz
94 ~7 ms ~150 Hz
95 ~13 ms ~75 Hz
96 ~27 ms ~37 Hz
97 ~55 ms ~18 Hz
98 ~110 ms ~9 Hz
99 ~220 ms ~4.5 Hz
9A ~440 ms ~2.3 Hz
9B ~0.8 s ~1.2 Hz
9C ~1.6 s ~0.6 Hz
9D ~3.3 s ~0.3 Hz
9E ~6.7 s ~0.015 Hz
9F ~13 s ~0.075 Hz
5.2.2 Alarm Mode
The MagI2C incorporates an Alarm Mode feature that sets the ALARM bit to “1” in the
CMM register whenever measurement results exceed an established limit. This feature
can be particularly useful for applications where the user’s device is briefly waking up to
take a magnetic field measurement reading and trying to determine if the field has
changed in an appreciable manner.
This is an optional feature and does not need to be implemented. To disable the feature,
the Alarm Lower Limit and Alarm Upper Limit register values should be `“0”, which are
the defaults.