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Adafruit_CircuitPython_BNO055/adafruit_bno055.py
Scott Shawcroft dfe23c84da Fix up init. Also add Design Guide compatible acceleration and 
magnetic properties. Orientation should be standardized but its
unclear what it should be.
2018-01-08 17:38:30 -08:00

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# The MIT License (MIT)
#
# Copyright (c) 2017 Radomir Dopieralski for Adafruit Industries.
#
# 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
# copies 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.
"""
``adafruit_bno055``
===================
This is a CircuitPython driver for the Bosch BNO055 nine degree of freedom
inertial measurement unit module with sensor fusion.
* Author(s): Radomir Dopieralski
"""
import time
from micropython import const
from adafruit_bus_device.i2c_device import I2CDevice
from adafruit_register.i2c_struct import Struct, UnaryStruct
__version__ = "0.0.0-auto.0"
__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_BNO055.git"
_CHIP_ID = const(0xa0)
CONFIG_MODE = const(0x00)
ACCONLY_MODE = const(0x01)
MAGONLY_MODE = const(0x02)
GYRONLY_MODE = const(0x03)
ACCMAG_MODE = const(0x04)
ACCGYRO_MODE = const(0x05)
MAGGYRO_MODE = const(0x06)
AMG_MODE = const(0x07)
IMUPLUS_MODE = const(0x08)
COMPASS_MODE = const(0x09)
M4G_MODE = const(0x0a)
NDOF_FMC_OFF_MODE = const(0x0b)
NDOF_MODE = const(0x0c)
_POWER_NORMAL = const(0x00)
_POWER_LOW = const(0x01)
_POWER_SUSPEND = const(0x02)
_MODE_REGISTER = const(0x3d)
_PAGE_REGISTER = const(0x07)
_TRIGGER_REGISTER = const(0x3f)
_POWER_REGISTER = const(0x3e)
_ID_REGISTER = const(0x00)
class _ScaledReadOnlyStruct(Struct): # pylint: disable=too-few-public-methods
def __init__(self, register_address, struct_format, scale):
super(_ScaledReadOnlyStruct, self).__init__(
register_address, struct_format)
self.scale = scale
def __get__(self, obj, objtype=None):
result = super(_ScaledReadOnlyStruct, self).__get__(obj, objtype)
return tuple(self.scale * v for v in result)
def __set__(self, obj, value):
raise NotImplementedError()
class _ReadOnlyUnaryStruct(UnaryStruct): # pylint: disable=too-few-public-methods
def __set__(self, obj, value):
raise NotImplementedError()
class BNO055:
"""
Driver for the BNO055 9DOF IMU sensor.
"""
temperature = _ReadOnlyUnaryStruct(0x34, 'B')
"""Measures the temperature of the chip in degrees Celsius."""
accelerometer = _ScaledReadOnlyStruct(0x08, '<hhh', 1/100)
"""Gives the raw accelerometer readings, in m/s.
.. warning:: This is deprecated. Use `acceleration` instead. It'll work
with other drivers too."""
acceleration = _ScaledReadOnlyStruct(0x08, '<hhh', 1/100)
"""Gives the raw accelerometer readings, in m/s."""
magnetometer = _ScaledReadOnlyStruct(0x0e, '<hhh', 1/16)
"""Gives the raw magnetometer readings in microteslas.
.. warning:: This is deprecated. Use `magnetic` instead. It'll work with
other drivers too."""
magnetic = _ScaledReadOnlyStruct(0x0e, '<hhh', 1/16)
"""Gives the raw magnetometer readings in microteslas."""
gyroscope = _ScaledReadOnlyStruct(0x14, '<hhh', 1/900)
"""Gives the raw gyroscope reading in degrees per second."""
euler = _ScaledReadOnlyStruct(0x1a, '<hhh', 1/16)
"""Gives the calculated orientation angles, in degrees."""
quaternion = _ScaledReadOnlyStruct(0x20, '<hhhh', 1/(1<<14))
"""Gives the calculated orientation as a quaternion."""
linear_acceleration = _ScaledReadOnlyStruct(0x28, '<hhh', 1/100)
"""Returns the linear acceleration, without gravity, in m/s."""
gravity = _ScaledReadOnlyStruct(0x2e, '<hhh', 1/100)
"""Returns the gravity vector, without acceleration in m/s."""
def __init__(self, i2c, address=0x28):
self.i2c_device = I2CDevice(i2c, address)
self.buffer = bytearray(2)
chip_id = self._read_register(_ID_REGISTER)
if chip_id != _CHIP_ID:
raise RuntimeError("bad chip id (%x != %x)" % (chip_id, _CHIP_ID))
self.reset()
self._write_register(_POWER_REGISTER, _POWER_NORMAL)
self._write_register(_PAGE_REGISTER, 0x00)
self._write_register(_TRIGGER_REGISTER, 0x00)
time.sleep(0.01)
self.mode = NDOF_MODE
time.sleep(0.01)
def _write_register(self, register, value):
self.buffer[0] = register
self.buffer[1] = value
with self.i2c_device as i2c:
i2c.write(self.buffer)
def _read_register(self, register):
self.buffer[0] = register
with self.i2c_device as i2c:
i2c.write(self.buffer, end=1, stop=False)
i2c.readinto(self.buffer, start=1)
return self.buffer[1]
def reset(self):
"""Resets the sensor to default settings."""
self.mode = CONFIG_MODE
try:
self._write_register(_TRIGGER_REGISTER, 0x20)
except OSError: # error due to the chip resetting
pass
while True: # wait for the chip to reset
time.sleep(0.01)
try:
chip_id = self._read_register(_ID_REGISTER)
except OSError:
chip_id = 0
if chip_id == _CHIP_ID:
break
@property
def mode(self):
"""
Switch the mode of operation and return the previous mode.
Mode of operation defines which sensors are enabled and whether the
measurements are absolute or relative:
+------------------+-------+---------+------+----------+
| Mode | Accel | Compass | Gyro | Absolute |
+==================+=======+=========+======+==========+
| CONFIG_MODE | - | - | - | - |
+------------------+-------+---------+------+----------+
| ACCONLY_MODE | X | - | - | - |
+------------------+-------+---------+------+----------+
| MAGONLY_MODE | - | X | - | - |
+------------------+-------+---------+------+----------+
| GYRONLY_MODE | - | - | X | - |
+------------------+-------+---------+------+----------+
| ACCMAG_MODE | X | X | - | - |
+------------------+-------+---------+------+----------+
| ACCGYRO_MODE | X | - | X | - |
+------------------+-------+---------+------+----------+
| MAGGYRO_MODE | - | X | X | - |
+------------------+-------+---------+------+----------+
| AMG_MODE | X | X | X | - |
+------------------+-------+---------+------+----------+
| IMUPLUS_MODE | X | - | X | - |
+------------------+-------+---------+------+----------+
| COMPASS_MODE | X | X | - | X |
+------------------+-------+---------+------+----------+
| M4G_MODE | X | X | - | - |
+------------------+-------+---------+------+----------+
| NDOF_FMC_OFF_MODE| X | X | X | X |
+------------------+-------+---------+------+----------+
| NDOF_MODE | X | X | X | X |
+------------------+-------+---------+------+----------+
The default mode is ``NDOF_MODE``.
"""
return self._read_register(_MODE_REGISTER)
@mode.setter
def mode(self, new_mode):
self._write_register(_MODE_REGISTER, new_mode)
@property
def external_crystal(self):
"""Switches the use of external crystal on or off."""
last_mode = self.mode
self.mode = CONFIG_MODE
self._write_register(_PAGE_REGISTER, 0x00)
value = self._read_register(_TRIGGER_REGISTER)
self.mode = last_mode
return value == 0x80
@external_crystal.setter
def use_external_crystal(self, value):
last_mode = self.mode
self.mode = CONFIG_MODE
self._write_register(_PAGE_REGISTER, 0x00)
self._write_register(_TRIGGER_REGISTER, 0x80 if value else 0x00)
self.mode = last_mode
time.sleep(0.01)
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