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tuupola / micropython-mpu9250

MicroPython I2C driver for MPU9250 9-axis motion tracking device
MIT License
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gy91 mpu9255 and new ak8963 #12

Open hortovanyi opened 5 years ago

hortovanyi commented 5 years ago

Using a gy-91 which contains a mpu9255 and a different model AK8963

Changed in AK8963.init if 0x48 != self.whoami: to if self.whoami not in (0x48,0x5F):

in AK8963.magnetic (was getting the same y an z values, appears you can no longer read six bytes at a time but must read 2 bytes for each of hxl, hyl, hzl) So changed xyz = list(self._register_three_shorts(_HXL) to

x = self._register_short(_HXL)
y = self._register_short(_HYL)
z = self._register_short(_HZL)
xyz=[x,y,z]

and in mpu6500.init if 0x71 != self.whoami to if self.whoami not in (0x71,0x73)

Still working away trying to get this working ...

tuupola commented 5 years ago

You mean this? Looks quite interesting board. Let me know how it goes.

hortovanyi commented 5 years ago

Cant seem to get this to work properly .. when I plot all the graphs for calibration the data doesnt look correct. Heres the MPU-9255 register map

Sample output and the code follows

6.53933,-1.681542,-6.165654
-42.7859,-6.165654,-12.14447
-42.41222,-12.14447,-12.14447
-6.165654,-12.14447,-12.14447
-6.165654,-24.84945,-12.14447
-3.176246,-36.05973,-12.14447
-1.681542,-39.04914,-12.14447
6.913006,-41.2912,-15.13388
-37.55444,-39.04914,-12.14447
-30.82827,-24.47578,-12.14447
-36.43341,-6.165654,-12.14447
-37.74128,-5.231464,-15.13388
-42.41222,-46.89634,-12.14447
-42.7859,-46.89634,-12.14447
-0.560514,-42.22539,-12.14447
0.0,-36.43341,-12.33131
-45.77531,-30.08092,-12.14447
3.923598,17.74961,-12.14447
-42.7859,-25.59681,-6.165654
-42.7859,-27.09151,-6.165654
-42.22539,-27.09151,-6.165654
-43.90693,-30.26776,-6.165654
-43.53325,-30.08092,-6.165654
-1.681542,-30.08092,-6.165654
-3.176246,-30.82827,-6.165654
-3.176246,-30.08092,-6.165654
-3.176246,-34.9387,-6.165654
-1.681542,-30.08092,-6.165654
-3.176246,-30.08092,-6.165654
-3.176246,-36.43341,-6.165654
-6.165654,-37.55444,-6.165654
-6.165654,-40.73068,-6.165654
-6.165654,-42.7859,-6.165654
-6.165654,-0.186838,-12.14447
-6.165654,-1.681542,-6.165654
-6.165654,-6.165654,-6.165654
-12.14447,-6.165654,-6.165654
-12.14447,-12.89182,-6.165654
-12.14447,-12.14447,-6.165654
-6.165654,-12.14447,-12.14447
-6.165654,-12.14447,-12.14447
-6.165654,-24.1021,-12.14447
-3.176246,-30.08092,-12.14447
-3.176246,-30.08092,-12.14447
-0.186838,-30.08092,-12.14447
-1.681542,-30.08092,-12.14447
-45.40164,-39.04914,-12.14447
-43.72009,-39.04914,-12.14447
-37.55444,-43.53325,-12.14447
-37.55444,-45.96215,-6.165654
-37.55444,-43.90693,-12.14447
-30.08092,-42.22539,-12.14447
-30.08092,-0.560514,-12.14447
-30.82827,-45.40164,-12.14447
-27.09151,-0.93419,-6.165654
-12.14447,-0.93419,-6.165654
-12.14447,-0.93419,-6.165654
-12.14447,-0.93419,-12.14447
-12.14447,-1.681542,-12.14447
-12.14447,-0.560514,-12.14447
-6.165654,-46.52266,-12.14447
-3.176246,-46.52266,-6.165654
-1.681542,-42.7859,-12.14447
50.81994,-39.79649,-12.14447
53.062,-39.04914,-12.14447
55.11721,-33.81768,-202.7192
-30.08092,-30.08092,-250.5497
-34.9387,-24.47578,-11.02344
62.96441,-12.14447,-6.165654
-30.82827,-12.14447,-6.165654
-30.08092,-12.14447,-12.14447
-30.08092,-25.59681,-6.165654
-39.42282,-36.05973,-6.165654
48.39104,-41.2912,-6.165654
-13.63917,-1.681542,-6.165654
-12.14447,-0.93419,-6.165654
15.32072,-47.08318,-12.14447
7.47352,-44.84112,-12.14447
# Copyright (c) 2018-2019 Mika Tuupola
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of  this software and associated documentation files (the "Software"), to
# deal in  the Software without restriction, including without limitation the
# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
# sell copied of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

# https://github.com/tuupola/micropython-mpu9250
# https://www.akm.com/akm/en/file/datasheet/AK8963C.pdf

"""
MicroPython I2C driver for AK8963 magnetometer
"""

__version__ = "0.2.1"

# pylint: disable=import-error
import ustruct
import utime
from machine import I2C, Pin
from micropython import const
# pylint: enable=import-error

_WIA = const(0x00)
_INFO = const(0x01)
_ST1 = const(0x02)
_HXL = const(0x03)
_HXH = const(0x04)
_HYL = const(0x05)
_HYH = const(0x06)
_HZL = const(0x07)
_HZH = const(0x08)
_ST2 = const(0x09)
_CNTL1 = const(0x0a)
_ASAX = const(0x10)
_ASAY = const(0x11)
_ASAZ = const(0x12)

_MODE_POWER_DOWN = 0b00000000
MODE_SINGLE_MEASURE = 0b00000001
MODE_CONTINOUS_MEASURE_1 = 0b00000010 # 8Hz
MODE_CONTINOUS_MEASURE_2 = 0b00000110 # 100Hz
MODE_EXTERNAL_TRIGGER_MEASURE = 0b00000100
_MODE_SELF_TEST = 0b00001000
_MODE_FUSE_ROM_ACCESS = 0b00001111

OUTPUT_14_BIT = 0b00000000
OUTPUT_16_BIT = 0b00010000

_SO_14BIT = 0.6 # μT per digit when 14bit mode
_SO_16BIT = 4912/32760 # μT per digit when 16bit mode

DRDY = 0b00000001
DOR = 0b00000010
HOFL = 0b00001000

class AK8963:
    """Class which provides interface to AK8963 magnetometer."""
    def __init__(
        self, i2c, address=0x0c,
        mode=MODE_CONTINOUS_MEASURE_2, output=OUTPUT_16_BIT,
        offset=(0, 0, 0), scale=(1, 1, 1)
    ):
        self.i2c = i2c
        self.address = address
        self._offset = offset
        self._scale = scale

    self._raw_buf_x = bytearray(2)
    self._raw_buf_y = bytearray(2)
    self._raw_buf_z = bytearray(2)
    self._raw_xyz = [0.0,0.0,0.0]

        #if 0x48 != self.whoami:
    whoami = self.whoami
    if whoami not in (0x48,0x5F,0x7F):
            raise RuntimeError("AK8963 not found in I2C bus - found 0x%02X." % whoami)

        # Sensitivity adjustement values
        self._register_char(_CNTL1, _MODE_FUSE_ROM_ACCESS)
        asax = self._register_char(_ASAX)
        asay = self._register_char(_ASAY)
        asaz = self._register_char(_ASAZ)
        self._register_char(_CNTL1, _MODE_POWER_DOWN)

        # Should wait atleast 100us before next mode
        self._adjustement = (
            (0.5 * (asax - 128)) / 128 + 1,
            (0.5 * (asay - 128)) / 128 + 1,
            (0.5 * (asaz - 128)) / 128 + 1
        )
        utime.sleep_us(100)

        # Power on
        self._register_char(_CNTL1, (mode | output))

        if output is OUTPUT_16_BIT:
            self._so = _SO_16BIT
        else:
            self._so = _SO_14BIT

    @property
    def magnetic(self):
        """
        X, Y, Z axis micro-Tesla (uT) as floats.
        """

    while not self.data_is_ready:
        utime.sleep_ms(10)
        pass

    self.i2c.readfrom_mem_into(self.address, _HXL, self._raw_buf_x)
    self.i2c.readfrom_mem_into(self.address, _HYL, self._raw_buf_y)
    self.i2c.readfrom_mem_into(self.address, _HZL, self._raw_buf_z)

    if not self.magnetic_sensor_overflow:
        self._raw_xyz[0] = self._read_int(self._raw_buf_x)
        self._raw_xyz[1] = self._read_int(self._raw_buf_y)
        self._raw_xyz[2] = self._read_int(self._raw_buf_z)

    xyz=self._raw_xyz

        #self._register_char(_ST2) # Enable updating readings again

        # Apply factory axial sensitivy adjustements
        xyz[0] *= self._adjustement[0]
        xyz[1] *= self._adjustement[1]
        xyz[2] *= self._adjustement[2]

        # Apply output scale determined in constructor
        so = self._so
        xyz[0] *= so
        xyz[1] *= so
        xyz[2] *= so

        # Apply hard iron ie. offset bias from calibration
        xyz[0] -= self._offset[0]
        xyz[1] -= self._offset[1]
        xyz[2] -= self._offset[2]

        # Apply soft iron ie. scale bias from calibration
        xyz[0] *= self._scale[0]
        xyz[1] *= self._scale[1]
        xyz[2] *= self._scale[2]

        return tuple(xyz)

    @property
    def adjustement(self):
        return self._adjustement

    @property
    def whoami(self):
        """ Value of the whoami register. """
        return self._register_char(_WIA)

    @property
    def data_is_ready(self):
        return bool(self._register_char(_ST1) & DRDY)

    @property
    def data_overrun(self):
        return bool(self._register_char(_ST1) & DOR)

    @property
    def magnetic_sensor_overflow(self):
    return bool(self._register_char(_ST2) & HOFL)

    def calibrate(self, count=256, delay=200):
        self._offset = (0, 0, 0)
        self._scale = (1, 1, 1)

        reading = self.magnetic
        minx = maxx = reading[0]
        miny = maxy = reading[1]
        minz = maxz = reading[2]

        while count:
            utime.sleep_ms(delay)
            reading = self.magnetic
            minx = min(minx, reading[0])
            maxx = max(maxx, reading[0])
            miny = min(miny, reading[1])
            maxy = max(maxy, reading[1])
            minz = min(minz, reading[2])
            maxz = max(maxz, reading[2])
            count -= 1

        # Hard iron correction
        offset_x = (maxx + minx) / 2
        offset_y = (maxy + miny) / 2
        offset_z = (maxz + minz) / 2

        self._offset = (offset_x, offset_y, offset_z)

        # Soft iron correction
        avg_delta_x = (maxx - minx) / 2
        avg_delta_y = (maxy - miny) / 2
        avg_delta_z = (maxz - minz) / 2

        avg_delta = (avg_delta_x + avg_delta_y + avg_delta_z) / 3

        scale_x = avg_delta / avg_delta_x
        scale_y = avg_delta / avg_delta_y
        scale_z = avg_delta / avg_delta_z

        self._scale = (scale_x, scale_y, scale_z)

        return self._offset, self._scale

    def _read_int(self, buf=bytearray(2)):
    value = (buf[1] <<8) + buf[0]
    if (value >= 0x8000):
        return -((65535 - value) + 1)
    else:
        return value

    def _register_short(self, register, value=None, buf=bytearray(2)):
        if value is None:
            self.i2c.readfrom_mem_into(self.address, register, buf)
            return ustruct.unpack("<h", buf)[0]

        ustruct.pack_into("<h", buf, 0, value)
        return self.i2c.writeto_mem(self.address, register, buf)

    def _register_three_shorts(self, register, buf=bytearray(6)):
        self.i2c.readfrom_mem_into(self.address, register, buf)
        return ustruct.unpack("<hhh", buf)

    def _register_char(self, register, value=None, buf=bytearray(1)):
        if value is None:
            self.i2c.readfrom_mem_into(self.address, register, buf)
            return buf[0]

        ustruct.pack_into("<b", buf, 0, value)
        return self.i2c.writeto_mem(self.address, register, buf)

    def __enter__(self):
        return self

    def __exit__(self, exception_type, exception_value, traceback):
        pass
hortovanyi commented 5 years ago

Getting better data using i2c = I2C(scl=Pin(21), sda=Pin(22), freq=100000). There appears to be an issue with the default freq on an ESP32 communicating with the GY-91. Might be a timing issues?

Tokelu commented 4 years ago

@hortovanyi Did you get this to work? I have been looking into using th GY-91 with a LoPy4. The LoPy is running µ-Python and getting the IMU to work has but me in some deep waters i have to admit, so I was looking for something to a library or driver for the GY-91

gretel commented 4 years ago

seems like a common issue.. https://hackaday.io/project/28491-quick-draw-motion-tracking/log/71828-a-spark-a-doh-a-surprise-and-data-sheets

gretel commented 4 years ago

working fine for me using MicroPython v1.13-186-g5a7027915 on 2020-11-25; ESP module with ESP8266:

ℹ️ the gy-91 datasheet states 100 and 400khz as the only rates supported.

some seconds running:

acc (1.5275, -0.462081, 10.6111)
gyr (0.277387, 3.5177, -0.50388)
mag (10.4332, 20.6402, 1.39219)
tmp 31.0009
--
acc (-0.390255, 0.0766144, 9.69173)
gyr (0.0141225, 0.00106585, -0.0150551)
mag (12.232, 27.8824, 2.78437)
tmp 30.7134
--
acc (-0.301669, 0.0861912, 9.66539)
gyr (0.0222496, -0.0226493, -0.0159877)
mag (12.4119, 27.3392, 1.21816)
tmp 30.5217
--
acc (-0.332794, 0.100556, 9.742)
gyr (0.0209173, -0.0434334, -0.0190521)
mag (11.8723, 27.1582, 2.43633)
tmp 30.5217
--
acc (-0.28491, 0.0742202, 9.61511)
gyr (0.0182527, -0.013856, -0.0123905)
mag (13.3113, 26.434, 3.13242)
tmp 30.6654
--
acc (-0.299275, 0.083797, 9.72046)
gyr (0.0199847, -0.0110582, -0.0163874)
mag (13.3113, 26.0719, 3.13242)
tmp 30.5217
--
acc (-0.299275, 0.047884, 9.64145)
gyr (0.0225161, 0.0214502, -0.0151884)
mag (12.232, 26.434, 2.08828)
tmp 30.0904
--
Alex-CodeLab commented 2 years ago

Any luck with this?

I'm getting similar results, but it doesn't seem right (only the temp seems to be correct)

acce  (-0.02154782, -0.02154782, 9.289502)
gyro  (-0.05249311, 0.01985146, -0.02264931)
magn  (-12.14364, -9.666079, 7.323508)
temp  27.6463

acce  (-0.01197101, -0.06943185, 9.315839)
gyro  (-0.05342574, 0.02251608, -0.01891884)
magn  (-11.57441, -9.490331, 6.794097)
temp  27.79007

acce  (-0.01197101, -0.05027823, 9.344569)
gyro  (-0.05449158, 0.01998469, -0.02118377)
magn  (-11.76415, -10.72056, 5.911747)
temp  27.6463

acce  (-0.01197101, -0.02394202, 9.358934)
gyro  (-0.05315928, 0.02451455, -0.02251608)
magn  (-11.19492, -9.490331, 6.794097)
temp  27.79007
ttyyzz34 commented 1 year ago

Cant seem to get this to work properly .. when I plot all the graphs for calibration the data doesnt look correct. Heres the MPU-9255 register map

Sample output and the code follows

6.53933,-1.681542,-6.165654
-42.7859,-6.165654,-12.14447
-42.41222,-12.14447,-12.14447
-6.165654,-12.14447,-12.14447
-6.165654,-24.84945,-12.14447
-3.176246,-36.05973,-12.14447
-1.681542,-39.04914,-12.14447
6.913006,-41.2912,-15.13388
-37.55444,-39.04914,-12.14447
-30.82827,-24.47578,-12.14447
-36.43341,-6.165654,-12.14447
-37.74128,-5.231464,-15.13388
-42.41222,-46.89634,-12.14447
-42.7859,-46.89634,-12.14447
-0.560514,-42.22539,-12.14447
0.0,-36.43341,-12.33131
-45.77531,-30.08092,-12.14447
3.923598,17.74961,-12.14447
-42.7859,-25.59681,-6.165654
-42.7859,-27.09151,-6.165654
-42.22539,-27.09151,-6.165654
-43.90693,-30.26776,-6.165654
-43.53325,-30.08092,-6.165654
-1.681542,-30.08092,-6.165654
-3.176246,-30.82827,-6.165654
-3.176246,-30.08092,-6.165654
-3.176246,-34.9387,-6.165654
-1.681542,-30.08092,-6.165654
-3.176246,-30.08092,-6.165654
-3.176246,-36.43341,-6.165654
-6.165654,-37.55444,-6.165654
-6.165654,-40.73068,-6.165654
-6.165654,-42.7859,-6.165654
-6.165654,-0.186838,-12.14447
-6.165654,-1.681542,-6.165654
-6.165654,-6.165654,-6.165654
-12.14447,-6.165654,-6.165654
-12.14447,-12.89182,-6.165654
-12.14447,-12.14447,-6.165654
-6.165654,-12.14447,-12.14447
-6.165654,-12.14447,-12.14447
-6.165654,-24.1021,-12.14447
-3.176246,-30.08092,-12.14447
-3.176246,-30.08092,-12.14447
-0.186838,-30.08092,-12.14447
-1.681542,-30.08092,-12.14447
-45.40164,-39.04914,-12.14447
-43.72009,-39.04914,-12.14447
-37.55444,-43.53325,-12.14447
-37.55444,-45.96215,-6.165654
-37.55444,-43.90693,-12.14447
-30.08092,-42.22539,-12.14447
-30.08092,-0.560514,-12.14447
-30.82827,-45.40164,-12.14447
-27.09151,-0.93419,-6.165654
-12.14447,-0.93419,-6.165654
-12.14447,-0.93419,-6.165654
-12.14447,-0.93419,-12.14447
-12.14447,-1.681542,-12.14447
-12.14447,-0.560514,-12.14447
-6.165654,-46.52266,-12.14447
-3.176246,-46.52266,-6.165654
-1.681542,-42.7859,-12.14447
50.81994,-39.79649,-12.14447
53.062,-39.04914,-12.14447
55.11721,-33.81768,-202.7192
-30.08092,-30.08092,-250.5497
-34.9387,-24.47578,-11.02344
62.96441,-12.14447,-6.165654
-30.82827,-12.14447,-6.165654
-30.08092,-12.14447,-12.14447
-30.08092,-25.59681,-6.165654
-39.42282,-36.05973,-6.165654
48.39104,-41.2912,-6.165654
-13.63917,-1.681542,-6.165654
-12.14447,-0.93419,-6.165654
15.32072,-47.08318,-12.14447
7.47352,-44.84112,-12.14447
# Copyright (c) 2018-2019 Mika Tuupola
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of  this software and associated documentation files (the "Software"), to
# deal in  the Software without restriction, including without limitation the
# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
# sell copied of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

# https://github.com/tuupola/micropython-mpu9250
# https://www.akm.com/akm/en/file/datasheet/AK8963C.pdf

"""
MicroPython I2C driver for AK8963 magnetometer
"""

__version__ = "0.2.1"

# pylint: disable=import-error
import ustruct
import utime
from machine import I2C, Pin
from micropython import const
# pylint: enable=import-error

_WIA = const(0x00)
_INFO = const(0x01)
_ST1 = const(0x02)
_HXL = const(0x03)
_HXH = const(0x04)
_HYL = const(0x05)
_HYH = const(0x06)
_HZL = const(0x07)
_HZH = const(0x08)
_ST2 = const(0x09)
_CNTL1 = const(0x0a)
_ASAX = const(0x10)
_ASAY = const(0x11)
_ASAZ = const(0x12)

_MODE_POWER_DOWN = 0b00000000
MODE_SINGLE_MEASURE = 0b00000001
MODE_CONTINOUS_MEASURE_1 = 0b00000010 # 8Hz
MODE_CONTINOUS_MEASURE_2 = 0b00000110 # 100Hz
MODE_EXTERNAL_TRIGGER_MEASURE = 0b00000100
_MODE_SELF_TEST = 0b00001000
_MODE_FUSE_ROM_ACCESS = 0b00001111

OUTPUT_14_BIT = 0b00000000
OUTPUT_16_BIT = 0b00010000

_SO_14BIT = 0.6 # μT per digit when 14bit mode
_SO_16BIT = 4912/32760 # μT per digit when 16bit mode

DRDY = 0b00000001
DOR = 0b00000010
HOFL = 0b00001000

class AK8963:
    """Class which provides interface to AK8963 magnetometer."""
    def __init__(
        self, i2c, address=0x0c,
        mode=MODE_CONTINOUS_MEASURE_2, output=OUTPUT_16_BIT,
        offset=(0, 0, 0), scale=(1, 1, 1)
    ):
        self.i2c = i2c
        self.address = address
        self._offset = offset
        self._scale = scale

  self._raw_buf_x = bytearray(2)
  self._raw_buf_y = bytearray(2)
  self._raw_buf_z = bytearray(2)
  self._raw_xyz = [0.0,0.0,0.0]

        #if 0x48 != self.whoami:
  whoami = self.whoami
  if whoami not in (0x48,0x5F,0x7F):
            raise RuntimeError("AK8963 not found in I2C bus - found 0x%02X." % whoami)

        # Sensitivity adjustement values
        self._register_char(_CNTL1, _MODE_FUSE_ROM_ACCESS)
        asax = self._register_char(_ASAX)
        asay = self._register_char(_ASAY)
        asaz = self._register_char(_ASAZ)
        self._register_char(_CNTL1, _MODE_POWER_DOWN)

        # Should wait atleast 100us before next mode
        self._adjustement = (
            (0.5 * (asax - 128)) / 128 + 1,
            (0.5 * (asay - 128)) / 128 + 1,
            (0.5 * (asaz - 128)) / 128 + 1
        )
        utime.sleep_us(100)

        # Power on
        self._register_char(_CNTL1, (mode | output))

        if output is OUTPUT_16_BIT:
            self._so = _SO_16BIT
        else:
            self._so = _SO_14BIT

    @property
    def magnetic(self):
        """
        X, Y, Z axis micro-Tesla (uT) as floats.
        """

  while not self.data_is_ready:
      utime.sleep_ms(10)
      pass

  self.i2c.readfrom_mem_into(self.address, _HXL, self._raw_buf_x)
  self.i2c.readfrom_mem_into(self.address, _HYL, self._raw_buf_y)
  self.i2c.readfrom_mem_into(self.address, _HZL, self._raw_buf_z)

  if not self.magnetic_sensor_overflow:
      self._raw_xyz[0] = self._read_int(self._raw_buf_x)
      self._raw_xyz[1] = self._read_int(self._raw_buf_y)
      self._raw_xyz[2] = self._read_int(self._raw_buf_z)

  xyz=self._raw_xyz

        #self._register_char(_ST2) # Enable updating readings again

        # Apply factory axial sensitivy adjustements
        xyz[0] *= self._adjustement[0]
        xyz[1] *= self._adjustement[1]
        xyz[2] *= self._adjustement[2]

        # Apply output scale determined in constructor
        so = self._so
        xyz[0] *= so
        xyz[1] *= so
        xyz[2] *= so

        # Apply hard iron ie. offset bias from calibration
        xyz[0] -= self._offset[0]
        xyz[1] -= self._offset[1]
        xyz[2] -= self._offset[2]

        # Apply soft iron ie. scale bias from calibration
        xyz[0] *= self._scale[0]
        xyz[1] *= self._scale[1]
        xyz[2] *= self._scale[2]

        return tuple(xyz)

    @property
    def adjustement(self):
        return self._adjustement

    @property
    def whoami(self):
        """ Value of the whoami register. """
        return self._register_char(_WIA)

    @property
    def data_is_ready(self):
        return bool(self._register_char(_ST1) & DRDY)

    @property
    def data_overrun(self):
        return bool(self._register_char(_ST1) & DOR)

    @property
    def magnetic_sensor_overflow(self):
  return bool(self._register_char(_ST2) & HOFL)

    def calibrate(self, count=256, delay=200):
        self._offset = (0, 0, 0)
        self._scale = (1, 1, 1)

        reading = self.magnetic
        minx = maxx = reading[0]
        miny = maxy = reading[1]
        minz = maxz = reading[2]

        while count:
            utime.sleep_ms(delay)
            reading = self.magnetic
            minx = min(minx, reading[0])
            maxx = max(maxx, reading[0])
            miny = min(miny, reading[1])
            maxy = max(maxy, reading[1])
            minz = min(minz, reading[2])
            maxz = max(maxz, reading[2])
            count -= 1

        # Hard iron correction
        offset_x = (maxx + minx) / 2
        offset_y = (maxy + miny) / 2
        offset_z = (maxz + minz) / 2

        self._offset = (offset_x, offset_y, offset_z)

        # Soft iron correction
        avg_delta_x = (maxx - minx) / 2
        avg_delta_y = (maxy - miny) / 2
        avg_delta_z = (maxz - minz) / 2

        avg_delta = (avg_delta_x + avg_delta_y + avg_delta_z) / 3

        scale_x = avg_delta / avg_delta_x
        scale_y = avg_delta / avg_delta_y
        scale_z = avg_delta / avg_delta_z

        self._scale = (scale_x, scale_y, scale_z)

        return self._offset, self._scale

    def _read_int(self, buf=bytearray(2)):
  value = (buf[1] <<8) + buf[0]
  if (value >= 0x8000):
      return -((65535 - value) + 1)
  else:
      return value

    def _register_short(self, register, value=None, buf=bytearray(2)):
        if value is None:
            self.i2c.readfrom_mem_into(self.address, register, buf)
            return ustruct.unpack("<h", buf)[0]

        ustruct.pack_into("<h", buf, 0, value)
        return self.i2c.writeto_mem(self.address, register, buf)

    def _register_three_shorts(self, register, buf=bytearray(6)):
        self.i2c.readfrom_mem_into(self.address, register, buf)
        return ustruct.unpack("<hhh", buf)

    def _register_char(self, register, value=None, buf=bytearray(1)):
        if value is None:
            self.i2c.readfrom_mem_into(self.address, register, buf)
            return buf[0]

        ustruct.pack_into("<b", buf, 0, value)
        return self.i2c.writeto_mem(self.address, register, buf)

    def __enter__(self):
        return self

    def __exit__(self, exception_type, exception_value, traceback):
        pass

Where did you change?I can use this code!