MicroPythonOS/lib/qmi8658.py

"""A simple driver for the QMI8658 IMU.

This driver is based on bjepson's CircuitPython driver.


MIT License

Copyright (c) 2024 Ethan Lacasse

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 (including the next
paragraph) 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.
"""
import struct
import time

from machine import I2C


# Sensor constants
_QMI8685_PARTID = const(0x05)
_REG_PARTID = const(0x00)
_REG_REVISION = const(0x01)

_REG_CTRL1 = const(0x02)  # Serial interface and sensor enable
_REG_CTRL2 = const(0x03)  # Accelerometer settings
_REG_CTRL3 = const(0x04)  # Gyroscope settings
_REG_CTRL4 = const(0x05)  # Magnetomer settings (support not implemented in this driver yet)
_REG_CTRL5 = const(0x06)  # Sensor data processing settings
_REG_CTRL6 = const(0x07)  # Attitude Engine ODR and Motion on Demand
_REG_CTRL7 = const(0x08)  # Enable Sensors and Configure Data Reads

_REG_TEMP = const(0x33)  # Temperature sensor.

_REG_AX_L = const(0x35)  # Read accelerometer
_REG_AX_H = const(0x36)
_REG_AY_L = const(0x37)
_REG_AY_H = const(0x38)
_REG_AZ_L = const(0x39)
_REG_AZ_H = const(0x3A)

_REG_GX_L = const(0x3B)  # read gyro
_REG_GX_H = const(0x3C)
_REG_GY_L = const(0x3D)
_REG_GY_H = const(0x3E)
_REG_GZ_L = const(0x3F)
_REG_GZ_H = const(0x40)

_QMI8658_I2CADDR_DEFAULT = const(0X6B)


_ACCELSCALE_RANGE_2G = const(0b00)
_ACCELSCALE_RANGE_4G = const(0b01)
_ACCELSCALE_RANGE_8G = const(0b10)
_ACCELSCALE_RANGE_16G = const(0b11)

_GYROSCALE_RANGE_16DPS = const(0b000)
_GYROSCALE_RANGE_32DPS = const(0b001)
_GYROSCALE_RANGE_64DPS = const(0b010)
_GYROSCALE_RANGE_128DPS = const(0b011)
_GYROSCALE_RANGE_256DPS = const(0b100)
_GYROSCALE_RANGE_512DPS = const(0b101)
_GYROSCALE_RANGE_1024DPS = const(0b110)
_GYROSCALE_RANGE_2048DPS = const(0b111)

_ODR_8000HZ = const(0b0000)
_ODR_4000HZ = const(0b0001)
_ODR_2000HZ = const(0b0010)
_ODR_1000HZ = const(0b0011)
_ODR_500HZ = const(0b0100)
_ODR_250HZ = const(0b0101)
_ODR_125HZ = const(0b0110)
_ODR_62_5HZ = const(0b0111)


class QMI8658:
    """QMI8658 inertial measurement unit."""

    def __init__(
            self,
            i2c_bus: I2C,
            address: int = _QMI8658_I2CADDR_DEFAULT,
            accel_scale: int = _ACCELSCALE_RANGE_8G,
            gyro_scale: int = _GYROSCALE_RANGE_256DPS):
        """Read from a sensor on the given I2C bus, at the given address."""
        self.i2c = i2c_bus
        self.address = address

        # Verify sensor part ID
        if self._read_u8(_REG_PARTID) != _QMI8685_PARTID:
            raise AttributeError("Cannot find a QMI8658")

        # Setup initial configuration
        self._configure_sensor(accel_scale, gyro_scale)

        # Configure scales/divisors for the driver
        self.acc_scale_divisor = {
            _ACCELSCALE_RANGE_2G: 1 << 14,
            _ACCELSCALE_RANGE_4G: 1 << 13,
            _ACCELSCALE_RANGE_8G: 1 << 12,
            _ACCELSCALE_RANGE_16G: 1 << 11,
        }[accel_scale]

        self.gyro_scale_divisor = {
            _GYROSCALE_RANGE_16DPS: 2048,
            _GYROSCALE_RANGE_32DPS: 1024,
            _GYROSCALE_RANGE_64DPS: 512,
            _GYROSCALE_RANGE_128DPS: 256,
            _GYROSCALE_RANGE_256DPS: 128,
            _GYROSCALE_RANGE_512DPS: 64,
            _GYROSCALE_RANGE_1024DPS: 32,
            _GYROSCALE_RANGE_2048DPS: 16,
        }[gyro_scale]


    def _configure_sensor(self, accel_scale: int, gyro_scale: int):
        # Initialize accelerometer and gyroscope settings
        self._write_u8(_REG_CTRL1, 0x60)  # Set SPI auto increment and big endian (Ctrl 1)
        self._write_u8(_REG_CTRL2, (accel_scale << 4) | _ODR_1000HZ)  # Accel Config
        self._write_u8(_REG_CTRL3, (gyro_scale << 4) | _ODR_1000HZ)  # Gyro Config
        self._write_u8(_REG_CTRL5, 0x01)  # Low-pass filter enable
        self._write_u8(_REG_CTRL7, 0x03)  # Enable accel and gyro
        time.sleep_ms(100)


    # Helper functions for register operations
    def _read_u8(self, reg:int) -> int:
        return self.i2c.readfrom_mem(self.address, reg, 1)[0]

    def _read_xyz(self, reg:int) -> tuple[int, int, int]:
        data = self.i2c.readfrom_mem(self.address, reg, 6)
        return struct.unpack('<hhh', data)

    def _write_u8(self, reg: int, value: int):
        self.i2c.writeto_mem(self.address, reg, bytes([value]))


    @property
    def temperature(self) -> float:
        """Get the device temperature."""
        temp_raw = self._read_u8(_REG_TEMP)
        return temp_raw / 256

    @property
    def acceleration(self) -> tuple[float, float, float]:
        """Get current acceleration reading."""
        raw_accel = self._read_xyz(_REG_AX_L)
        return tuple(val / self.acc_scale_divisor for val in raw_accel)

    @property
    def gyro(self) -> tuple[float, float, float]:
        """Get current gyroscope reading."""
        raw_gyro = self._read_xyz(_REG_GX_L)
        return tuple(val / self.gyro_scale_divisor for val in raw_gyro)