# The MIT License (MIT) # # Copyright (c) 2017 Dave Astels 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_LSM303` ==================================================== CircuitPython driver for the LSM303 accelerometer + magnetometer. * Author(s): Dave Astels """ try: import struct except ImportError: import ustruct as struct from micropython import const from adafruit_bus_device.i2c_device import I2CDevice __version__ = "1.1.0" __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_LSM303.git" # pylint: disable=bad-whitespace _ADDRESS_ACCEL = const(0x19) # (0x32 >> 1) // 0011001x _ADDRESS_MAG = const(0x1E) # (0x3C >> 1) // 0011110x _ID = const(0xD4) # (0b11010100) # Accelerometer registers _REG_ACCEL_CTRL_REG1_A = const(0x20) _REG_ACCEL_CTRL_REG2_A = const(0x21) _REG_ACCEL_CTRL_REG3_A = const(0x22) _REG_ACCEL_CTRL_REG4_A = const(0x23) _REG_ACCEL_CTRL_REG5_A = const(0x24) _REG_ACCEL_CTRL_REG6_A = const(0x25) _REG_ACCEL_REFERENCE_A = const(0x26) _REG_ACCEL_STATUS_REG_A = const(0x27) _REG_ACCEL_OUT_X_L_A = const(0x28) _REG_ACCEL_OUT_X_H_A = const(0x29) _REG_ACCEL_OUT_Y_L_A = const(0x2A) _REG_ACCEL_OUT_Y_H_A = const(0x2B) _REG_ACCEL_OUT_Z_L_A = const(0x2C) _REG_ACCEL_OUT_Z_H_A = const(0x2D) _REG_ACCEL_FIFO_CTRL_REG_A = const(0x2E) _REG_ACCEL_FIFO_SRC_REG_A = const(0x2F) _REG_ACCEL_INT1_CFG_A = const(0x30) _REG_ACCEL_INT1_SOURCE_A = const(0x31) _REG_ACCEL_INT1_THS_A = const(0x32) _REG_ACCEL_INT1_DURATION_A = const(0x33) _REG_ACCEL_INT2_CFG_A = const(0x34) _REG_ACCEL_INT2_SOURCE_A = const(0x35) _REG_ACCEL_INT2_THS_A = const(0x36) _REG_ACCEL_INT2_DURATION_A = const(0x37) _REG_ACCEL_CLICK_CFG_A = const(0x38) _REG_ACCEL_CLICK_SRC_A = const(0x39) _REG_ACCEL_CLICK_THS_A = const(0x3A) _REG_ACCEL_TIME_LIMIT_A = const(0x3B) _REG_ACCEL_TIME_LATENCY_A = const(0x3C) _REG_ACCEL_TIME_WINDOW_A = const(0x3D) # Magnetometer registers _REG_MAG_CRA_REG_M = const(0x00) _REG_MAG_CRB_REG_M = const(0x01) _REG_MAG_MR_REG_M = const(0x02) _REG_MAG_OUT_X_H_M = const(0x03) _REG_MAG_OUT_X_L_M = const(0x04) _REG_MAG_OUT_Z_H_M = const(0x05) _REG_MAG_OUT_Z_L_M = const(0x06) _REG_MAG_OUT_Y_H_M = const(0x07) _REG_MAG_OUT_Y_L_M = const(0x08) _REG_MAG_SR_REG_M = const(0x09) _REG_MAG_IRA_REG_M = const(0x0A) _REG_MAG_IRB_REG_M = const(0x0B) _REG_MAG_IRC_REG_M = const(0x0C) _REG_MAG_TEMP_OUT_H_M = const(0x31) _REG_MAG_TEMP_OUT_L_M = const(0x32) # Magnetometer gains MAGGAIN_1_3 = const(0x20) # +/- 1.3 MAGGAIN_1_9 = const(0x40) # +/- 1.9 MAGGAIN_2_5 = const(0x60) # +/- 2.5 MAGGAIN_4_0 = const(0x80) # +/- 4.0 MAGGAIN_4_7 = const(0xA0) # +/- 4.7 MAGGAIN_5_6 = const(0xC0) # +/- 5.6 MAGGAIN_8_1 = const(0xE0) # +/- 8.1 # Magentometer rates MAGRATE_0_7 = const(0x00) # 0.75 Hz MAGRATE_1_5 = const(0x01) # 1.5 Hz MAGRATE_3_0 = const(0x62) # 3.0 Hz MAGRATE_7_5 = const(0x03) # 7.5 Hz MAGRATE_15 = const(0x04) # 15 Hz MAGRATE_30 = const(0x05) # 30 Hz MAGRATE_75 = const(0x06) # 75 Hz MAGRATE_220 = const(0x07) # 200 Hz # Conversion constants _LSM303ACCEL_MG_LSB = 16704.0 _GRAVITY_STANDARD = 9.80665 # Earth's gravity in m/s^2 _GAUSS_TO_MICROTESLA = 100.0 # Gauss to micro-Tesla multiplier # pylint: enable=bad-whitespace class LSM303(object): """Driver for the LSM303 accelerometer/magnetometer.""" # Class-level buffer for reading and writing data with the sensor. # This reduces memory allocations but means the code is not re-entrant or # thread safe! _BUFFER = bytearray(6) def __init__(self, i2c): self._accel_device = I2CDevice(i2c, _ADDRESS_ACCEL) self._mag_device = I2CDevice(i2c, _ADDRESS_MAG) self._write_u8(self._accel_device, _REG_ACCEL_CTRL_REG1_A, 0x27) # Enable the accelerometer self._write_u8(self._mag_device, _REG_MAG_MR_REG_M, 0x00) # Enable the magnetometer self._lsm303mag_gauss_lsb_xy = 1100.0 self._lsm303mag_gauss_lsb_z = 980.0 self._mag_gain = MAGGAIN_1_3 self._mag_rate = MAGRATE_0_7 @property def raw_acceleration(self): """The raw accelerometer sensor values. A 3-tuple of X, Y, Z axis values that are 16-bit signed integers. """ self._read_bytes(self._accel_device, _REG_ACCEL_OUT_X_L_A | 0x80, 6, self._BUFFER) return struct.unpack_from('hhh', self._BUFFER[0:6]) return tuple([n >> 4 for n in raw_values]) @property def magnetic(self): """The processed magnetometer sensor values. A 3-tuple of X, Y, Z axis values in microteslas that are signed floats. """ mag_x, mag_y, mag_z = self.raw_magnetic return (mag_x / self._lsm303mag_gauss_lsb_xy * _GAUSS_TO_MICROTESLA, mag_y / self._lsm303mag_gauss_lsb_xy * _GAUSS_TO_MICROTESLA, mag_z / self._lsm303mag_gauss_lsb_z * _GAUSS_TO_MICROTESLA) @property def mag_gain(self): """The magnetometer's gain.""" return self._mag_gain @mag_gain.setter def mag_gain(self, value): assert value in (MAGGAIN_1_3, MAGGAIN_1_9, MAGGAIN_2_5, MAGGAIN_4_0, MAGGAIN_4_7, MAGGAIN_5_6, MAGGAIN_8_1) self._mag_gain = value self._write_u8(self._mag_device, _REG_MAG_CRB_REG_M, self._mag_gain) if self._mag_gain == MAGGAIN_1_3: self._lsm303mag_gauss_lsb_xy = 1100.0 self._lsm303mag_gauss_lsb_z = 980.0 elif self._mag_gain == MAGGAIN_1_9: self._lsm303mag_gauss_lsb_xy = 855.0 self._lsm303mag_gauss_lsb_z = 760.0 elif self._mag_gain == MAGGAIN_2_5: self._lsm303mag_gauss_lsb_xy = 670.0 self._lsm303mag_gauss_lsb_z = 600.0 elif self._mag_gain == MAGGAIN_4_0: self._lsm303mag_gauss_lsb_xy = 450.0 self._lsm303mag_gauss_lsb_z = 400.0 elif self._mag_gain == MAGGAIN_4_7: self._lsm303mag_gauss_lsb_xy = 400.0 self._lsm303mag_gauss_lsb_z = 355.0 elif self._mag_gain == MAGGAIN_5_6: self._lsm303mag_gauss_lsb_xy = 330.0 self._lsm303mag_gauss_lsb_z = 295.0 elif self._mag_gain == MAGGAIN_8_1: self._lsm303mag_gauss_lsb_xy = 230.0 self._lsm303mag_gauss_lsb_z = 205.0 @property def mag_rate(self): """The magnetometer update rate.""" return self._mag_rate @mag_rate.setter def mag_rate(self, value): assert value in (MAGRATE_0_7, MAGRATE_1_5, MAGRATE_3_0, MAGRATE_7_5, MAGRATE_15, MAGRATE_30, MAGRATE_75, MAGRATE_220) self._mag_rate = value reg_m = ((value & 0x07) << 2) & 0xFF self._write_u8(self._mag_device, _REG_MAG_CRA_REG_M, reg_m) def _read_u8(self, device, address): with device as i2c: self._BUFFER[0] = address & 0xFF i2c.write(self._BUFFER, end=1, stop=False) i2c.readinto(self._BUFFER, end=1) return self._BUFFER[0] def _write_u8(self, device, address, val): with device as i2c: self._BUFFER[0] = address & 0xFF self._BUFFER[1] = val & 0xFF i2c.write(self._BUFFER, end=2) @staticmethod def _read_bytes(device, address, count, buf): with device as i2c: buf[0] = address & 0xFF i2c.write(buf, end=1, stop=False) i2c.readinto(buf, end=count)