LSM303AH Datasheet, PDF (24/82 Pages) –

Functionality
Figure 5. Interrupt function
LSM303AH
Two different approaches for the interrupt function are available:
 Typical: comparison is between magnetic data read by the sensor and the
programmable threshold;
 Advanced: comparison is made between magnetic data after hard-iron correction and
the programmable threshold.
These approaches are configurable by setting the INT_on_DataOFF bit in CFG_REG_B_M
(61h).
If INT_on_DataOFF is set to '0' the typical approach is selected, otherwise if it is set to '1'
the advanced approach is selected.
Two different interrupts are available:
 Pulsed interrupt signal: it goes high when the magnetic data exceed one of the two
thresholds and goes low when the magnetic data are between the two thresholds. This
kind of interrupt is selected by setting the IEL bit in INT_CTRL_REG_M (63h) to '0'.
 Latched interrupt signal: it goes high when the data exceed one of the two thresholds
but is reset only once the source register is read and not when the magnetic data
returns between the two thresholds. This kind of interrupt is selected by setting the IEL
bit in INT_CTRL_REG_M (63h) to '1'.
The interrupt signal polarity can be set using the IEA bit in INT_CTRL_REG_M (63h).
If IEA is set to '1' then the interrupt signal is active high, while if it is set to '0' the interrupt
signal is active low.
In order to drive the interrupt signal from the DRDY pad, the INT_MAG_PIN bit in
CFG_REG_C_M (62h) must be set to '1'.
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