PNI RM3100 Evaluation Board - Manual (Page 21)

PNI Sensor Corporation Doc 1017252 r02
RM3100 Evaluation Board User Manual Page 20 of 33
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 RM3100 Evaluation Board 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.