Data Sheet

MLX90393
Micropower Triaxis® Magnetometer Datasheet
7. Functional Specification
The MLX90393 can operate in 3 modes:
• Burst mode
The ASIC will have a programmable data rate at which it will operate. This data rate implies auto-
wakeup and sequencing of the ASIC, flagging that data is ready on a dedicated pin (INT/DRDY). The
maximum data rate corresponds to continuous burst mode, and is a function of the chosen
measurement axes. For non-continuous burst modes, the time during which the ASIC has a counter
running but is not doing an actual conversion is called the Standby mode (STBY).
• Single Measure mode
The master will ask for data via the corresponding protocol (I
2
C or SPI), waking up the ASIC to make
a single conversion, immediately followed by an automatic return to sleep mode (IDLE) until the
next polling of the master. This polling can also be done by strobing the TRG pin instead, which has
the same effect as sending a protocol command for a single measurement.
• Wake-Up on Change
This mode is similar to the burst mode in the sense that the device will be auto-sequencing, with
the difference that the measured component(s) is/are compared with a reference and in case the
difference is bigger than a user-defined threshold, the DRDY signal is set on the designated pin. The
user can select which axes and/or temperature fall under this cyclic check, and which thresholds are
allowed.
The user can change the operating mode at all time through a specific command on the bus. The device
waits in IDLE mode after power-up, but with a proper user command any mode can be set after power-up.
Changing to Burst or WOC mode, coming from Single Measure mode, is always accompanied by a
measurement first. The top-level state diagram indicating the different modes and some relevant timing is
shown below in Figure 4. In the Measure state, the MDATA flag will define which components will be
measured (ZYXT). The order of conversion is defined as TXYZ and can not be modified by the user, only the
combination of axes is a degree of freedom.
Arrows indicated in grey are the direct result of an Exit command. The main difference between STANDBY
and WOC_IDLE is that in STANDBY mode, all analog circuitry is ready to make a conversion, but this is
accompanied by a larger current consumption than IDLE mode. For burst mode this extra current
consumption is justified because the emphasis is more on accurate timing intervals, avoiding the delay of
T
STBY
before conversion and supporting an efficient continuous burst mode without standby overhead.
It is the user’s responsibility to read back the measured data, the MLX90393 acts as a pure slave. Even in
burst mode and WOC mode when the MLX90393 is auto-sequencing, the master will be responsible for
collecting the acquired sensor data.
3901090393 Data Sheet
Rev002 Page 9 Feb-2015