2 alarm mode, Alarm mode, Table 5-4: cmm update rates – PNI RM3100 Sensor Suite User Manual

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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

, 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

~1.7 ms

~600 Hz

~3 ms

~300 Hz

~7 ms

~150 Hz

~13 ms

~75 Hz

~27 ms

~37 Hz

~55 ms

~18 Hz

~110 ms

~9 Hz

~220 ms

~4.5 Hz

~440 ms

~2.3 Hz

~0.8 s

~1.2 Hz

~1.6 s

~0.6 Hz

~3.3 s

~0.3 Hz

~6.7 s

~0.015 Hz

~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.