It is useful to document the bits,, and perhaps sorting them later by function, interaction, ones that have to be set a particular way to work with the module code. (A todo)

Magnetometer bits

TEMP_COMP

Temperature compensation enable. Default value: 0
(0: temperature compensation disabled; 1: temperature compensation enabled)
For the output of the magnetic data compensated by temperature, the
TEMP_COMP bit in CTRL_REG1_M (20h) must be set to ‘1’.

OM

0 = Low-power mode
1 = Medium-performance mode
2 = High-performance mode
3 = Ultra-high performance

DO

0 = 0.625 Hz.
1= 1.25
2 = 2.5
3 = 5
4 = 10
5 = 20
6 = 40
7 = 80

FAST_ODR

enables data rates higher than 80 Hz. Default value: 0
(0: Fast_ODR disabled; 1: FAST_ODR enabled)

ST

Self-test enable. Default value: 0
(0: self-test disabled; 1: self-test enabled)

FS

Full scale
0 = ± 4 gauss
1 = ± 8 gauss
2 = ± 12 gauss
3 = ± 16 gauss

REBOOT

Reboot memory content. Default value: 0
(0: normal mode; 1: reboot memory content)

SOFT_RST

Configuration registers and user register reset function.
(0: default value; 1: reset operation)

I2C_DISABLE

Disable I2C interface. Default value 0. (0: I2C enable; 1: I2C disable)

LP

Low-power mode configuration. Default value: 0
If this bit is ‘1’, the DO[2:0] is set to 0.625 Hz and the system performs, for each
channel, the minimum number of averages. Once the bit is set to ‘0’, the magnetic
data rate is configured by the DO bits in the CTRL_REG1_M (20h) register.

SIM

SPI Serial Interface mode selection. Default value: 0
(0: SPI only write operations enabled; 1: SPI read and write operations enable).

MD

Operating mode selection. Default value: 11
0 = Continuous-conversion mode
1 = Single-conversion mode
2 = Power-down mode
3 = Power-down mode
The magnetic sensor has three operating modes available: power-down (default),
continuous-conversion mode and single-conversion mode. Switching from power-down to
the other modes requires one write operation to CTRL_REG3_M (22h), setting values in the
MD[1:0] bits. For the output of the magnetic data compensated by temperature, the
TEMP_COMP bit in CTRL_REG1_M (20h) must be set to ‘1’.

OMZ

Z-axis operative mode selection
0 = Low-power mode
1 = Medium-performance mode
2 = High-performance mode
3 = Ultra-high performance mode

BLE

Big/Little Endian data selection. Default value: 0
(0: data LSb at lower address; 1: data MSb at lower address)

FAST_READ

FAST_READ allows reading the high part of DATA OUT only in order to increase
reading efficiency. Default value: 0
(0: FAST_READ disabled; 1: FAST_READ enabled)

BDU

Block data update for magnetic data. Default value: 0
(0: continuous update; 1: output registers not updated until MSB and LSB have
been read)

ZYXOR

X, Y and Z-axis data overrun. Default value: 0
(0: no overrun has occurred;
1: a new set of data has overwritten the previous set)

ZOR

Z-axis data overrun. Default value: 0
(0: no overrun has occurred;
1: new data for the Z-axis has overwritten the previous data)

YOR

Y-axis data overrun. Default value: 0
(0: no overrun has occurred;
1: new data for the Y-axis has overwritten the previous data)

XOR

X-axis data overrun. Default value: 0
(0: no overrun has occurred;
1: new data for the X-axis has overwritten the previous data)

ZYXDA

X, Y and Z-axis new data available. Default value: 0
(0: a new set of data is not yet available;
1: a new set of data is available)

ZDA

Z-axis new data available. Default value: 0
(0: new data for the Z-axis is not yet available;
1: new data for the Z-axis is available)

YDA

Y-axis new data available. Default value: 0
(0: new data for the Y-axis is not yet available;
1: new data for the Y-axis is available)

XDA

X-axis new data available. Default value: 0
(0: a new data for the X-axis is not yet available;
1: a new data for the X-axis is available)

XIEN

Enable interrupt generation on X-axis. Default value: 0
0: disable interrupt request; 1: enable interrupt request

YIEN

Enable interrupt generation on Y-axis. Default value: 0
0: disable interrupt request; 1: enable interrupt request

ZIEN

Enable interrupt generation on Z-axis. Default value: 0
0: disable interrupt request; 1: enable interrupt request

IEA

Interrupt active configuration on INT_MAG. Default value: 0
0: low; 1: high

IEL

Latch interrupt request. Default value: 0
0: interrupt request latched; 1: interrupt request not latched)
Once latched, the INT_M pin remains in the same state until INT_SRC_M (31h)) is
read.

IEN

Interrupt enable on the INT_M pin. Default value: 0
0: disable; 1: enable

PTH_X

Value on X-axis exceeds the threshold on the positive side.
Default value: 0

PTH_Y

Value on Y-axis exceeds the threshold on the positive side.
Default value: 0

PTH_Z

Value on Z-axis exceeds the threshold on the positive side.
Default value: 0

NTH_X

Value on X-axis exceeds the threshold on the negative side.
Default value: 0

NTH_Y

Value on Y-axis exceeds the threshold on the negative side.
Default value: 0

NTH_Z

Value on Z-axis exceeds the threshold on the negative side.
Default value: 0

MROI

Internal measurement range overflow on magnetic value.
Default value: 0

INT

This bit signals when the interrupt event occurs.