User's Manual

UMXXX
(FIFO threshold level), or when it is full, or when it overflows (overrun). The FIFO can
work in the following modes:
• Bypass mode: the FIFO buffer is disabled and cleared.
• FIFO mode: the FIFO buffer collects data until it is full, then stops.
• Continuous mode: the FIFO buffer collects data continuously, when it is full oldest
samples are overwritten as in a circular buffer. The host microcontroller may read
the data before it is overwritten thanks to the FIFO full and FIFO threshold level
interrupts.
• Continuous-to-FIFO mode: the FIFO buffer collects data continuously but switch to
FIFO mode as soon as the selected interrupt occurs. This mode is especially useful
to capture data before and after a specific event.
• Bypass-to-Continuous mode: the FIFO buffer is disabled but switch to continuous
mode as soon as the selected interrupt occurs. This mode is useful to capture data
after an event has occurred.
• Bypass-to-FIFO mode: the FIFO buffer is disabled but switch to FIFO mode as soon
as the selected interrupt occurs. This mode is useful to capture data after an event
has occurred. FIFO is filled and then data collection stops.
LIS2MDL DYNAMIC RANGE, RESOLUTION AND ACCURACY
The LIS2MDL is a 3D digital magnetometer. The magnetic field dynamic range is +/-50
Gauss (reduced to +/-25 Gauss if the magnetic field is not aligned with one of the axis); well
above the earth magnetic field level (which is typically in the range of 0.25 to 0.65 Gauss).
However, the resolution and accuracy is also high: the output is 16 bits (1.5 mgauss/LSB
+/-7%), the RMS noise level in high-performance mode is 3 mgauss (2LSB). This enables
applications such as accurate e-compass orientation estimation as well as distance
measurements from a reference magnet (in its simplest form: the magnetometer can
emulate a Reed-switch, a magnetically activated switch).
The LIS2MDL magnetometer can perform a single-shot measurement and then return to
power-down mode, or it can operate in continuous mode with a programmable sampling
rate (10, 20, 50 or 100 Hz). Single-shot measurements can be done at max 100 Hz in high-
performance mode, or max 150 Hz in low-power mode. In low-power mode the power
consumption is reduced to 25%, while in high-performance mode the RMS noise is halved.
An optional low-pass filter can be activated to further reduce RMS noise, without increasing
the power consumption, the bandwidth in this case is reduced from output data rate ODR/2
down to ODR/4.
LIS2MDL INTRINSIC OFFSET AUTOMATIC CANCELLATION