Make api more in line with others, clean up the I2C interface
This commit is contained in:
Dave Astels
parent
0fd97ae050
commit
35f4cac319
1 changed files with 40 additions and 55 deletions
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@ -112,17 +112,10 @@ MAGRATE_30 = const(0x05) # 30 Hz
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MAGRATE_75 = const(0x06) # 75 Hz
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MAGRATE_220 = const(0x07) # 200 Hz
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# Sensor types
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_ACCELTYPE = True
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_MAGTYPE = False
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# Conversion constants
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_LSM303ACCEL_MG_LSB = 16704.0 # 1, 2, 4 or 12 mg per lsb
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_LSM303MAG_GAUSS_LSB_XY = 1100.0 # Varies with gain
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_LSM303MAG_GAUSS_LSB_Z = 980.0 # Varies with gain
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_LSM303ACCEL_MG_LSB = 16704.0
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_GRAVITY_STANDARD = 9.80665 # Earth's gravity in m/s^2
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_GAUSS_TO_MICROTESLA = 100.0 # Gauss to micro-Tesla multiplier
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_GAUSS_TO_MICROTESLA = 100.0 # Gauss to micro-Tesla multiplier
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class LSM303(object):
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"""Driver for the LSM303 accelerometer/magnetometer."""
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@ -135,101 +128,101 @@ class LSM303(object):
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def __init__(self, i2c):
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self._accel_device = I2CDevice(i2c, _ADDRESS_ACCEL)
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self._mag_device = I2CDevice(i2c, _ADDRESS_MAG)
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self._write_u8(_ACCELTYPE, _REG_ACCEL_CTRL_REG1_A, 0x27) # Enable the accelerometer
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self._write_u8(_MAGTYPE, _REG_MAG_MR_REG_M, 0x00) # Enable the magnetometer
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self._write_u8(self._accel_device, _REG_ACCEL_CTRL_REG1_A, 0x27) # Enable the accelerometer
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self._write_u8(self._mag_device, _REG_MAG_MR_REG_M, 0x00) # Enable the magnetometer
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self._lsm303mag_gauss_lsb_xy = 1100.0
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self._lsm303mag_gauss_lsb_z = 980.0
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self._mag_gain = MAGGAIN_1_3
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self._mag_rate = MAGRATE_0_7
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@property
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def raw_accel(self):
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def raw_accelerometer(self):
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"""The raw accelerometer sensor values.
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A 3-tuple of X, Y, Z axis values that are 16-bit signed integers.
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"""
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self._read_bytes(_ACCELTYPE, _REG_ACCEL_OUT_X_L_A | 0x80, 6, self._BUFFER)
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self._read_bytes(self._accel_device, _REG_ACCEL_OUT_X_L_A | 0x80, 6, self._BUFFER)
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return struct.unpack_from('<hhh', self._BUFFER[0:6])
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@property
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def accel(self):
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def accelerometer(self):
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"""The processed accelerometer sensor values.
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A 3-tuple of X, Y, Z axis values in meters per second squared that are signed floats.
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"""
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raw_accel_data = self.raw_accel
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raw_accel_data = self.raw_accelerometer
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return [n / _LSM303ACCEL_MG_LSB * _GRAVITY_STANDARD for n in raw_accel_data]
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@property
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def raw_mag(self):
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def raw_magnetometer(self):
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"""The raw magnetometer sensor values.
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A 3-tuple of X, Y, Z axis values that are 16-bit signed integers.
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"""
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self._read_bytes(_MAGTYPE, _REG_MAG_OUT_X_H_M, 6, self._BUFFER)
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self._read_bytes(self._mag_device, _REG_MAG_OUT_X_H_M, 6, self._BUFFER)
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raw_values = struct.unpack_from('>hhh', self._BUFFER[0:6])
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return [n >> 4 for n in raw_values]
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@property
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def mag(self):
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def magnetometer(self):
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"""The processed magnetometer sensor values.
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A 3-tuple of X, Y, Z axis values in microteslas that are signed floats.
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"""
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mag_x, mag_y, mag_z = self.raw_mag
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return (mag_x / _LSM303MAG_GAUSS_LSB_XY * _GAUSS_TO_MICROTESLA,
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mag_y / _LSM303MAG_GAUSS_LSB_XY * _GAUSS_TO_MICROTESLA,
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mag_z / _LSM303MAG_GAUSS_LSB_Z * _GAUSS_TO_MICROTESLA)
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mag_x, mag_y, mag_z = self.raw_magnetometer
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return (mag_x / self._lsm303mag_gauss_lsb_xy * _GAUSS_TO_MICROTESLA,
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mag_y / self._lsm303mag_gauss_lsb_xy * _GAUSS_TO_MICROTESLA,
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mag_z / self._lsm303mag_gauss_lsb_z * _GAUSS_TO_MICROTESLA)
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@property
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def mag_gain(self):
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"""The magnetometer's gain."""
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return self._mag_gain
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@mag_gain.setter
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def mag_gain(self, value):
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"""The magnetometer's gain."""
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assert value in (MAGGAIN_1_3, MAGGAIN_1_9, MAGGAIN_2_5, MAGGAIN_4_0, MAGGAIN_4_7, MAGGAIN_5_6, MAGGAIN_8_1)
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self._mag_gain = value
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self._write_u8(_MAGTYPE, _REG_MAG_CRB_REG_M, self._mag_gain)
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self._write_u8(self._mag_device, _REG_MAG_CRB_REG_M, self._mag_gain)
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if self._mag_gain == MAGGAIN_1_3:
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_LSM303MAG_GAUSS_LSB_XY = 1100.0
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_LSM303MAG_GAUSS_LSB_Z = 980.0
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self._lsm303mag_gauss_lsb_xy = 1100.0
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self._lsm303mag_gauss_lsb_z = 980.0
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elif self._mag_gain == MAGGAIN_1_9:
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_LSM303MAG_GAUSS_LSB_XY = 855.0
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_LSM303MAG_GAUSS_LSB_Z = 760.0
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self._lsm303mag_gauss_lsb_xy = 855.0
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self._lsm303mag_gauss_lsb_z = 760.0
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elif self._mag_gain == MAGGAIN_2_5:
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_LSM303MAG_GAUSS_LSB_XY = 670.0
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_LSM303MAG_GAUSS_LSB_Z = 600.0
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self._lsm303mag_gauss_lsb_xy = 670.0
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self._lsm303mag_gauss_lsb_z = 600.0
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elif self._mag_gain == MAGGAIN_4_0:
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_LSM303MAG_GAUSS_LSB_XY = 450.0
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_LSM303MAG_GAUSS_LSB_Z = 400.0
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self._lsm303mag_gauss_lsb_xy = 450.0
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self._lsm303mag_gauss_lsb_z = 400.0
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elif self._mag_gain == MAGGAIN_4_7:
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_LSM303MAG_GAUSS_LSB_XY = 400.0
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_LSM303MAG_GAUSS_LSB_Z = 355.0
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self._lsm303mag_gauss_lsb_xy = 400.0
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self._lsm303mag_gauss_lsb_z = 355.0
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elif self._mag_gain == MAGGAIN_5_6:
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_LSM303MAG_GAUSS_LSB_XY = 330.0
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_LSM303MAG_GAUSS_LSB_Z = 295.0
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self._lsm303mag_gauss_lsb_xy = 330.0
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self._lsm303mag_gauss_lsb_z = 295.0
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elif self._mag_gain == MAGGAIN_8_1:
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_LSM303MAG_GAUSS_LSB_XY = 230.0
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_LSM303MAG_GAUSS_LSB_Z = 205.0
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self._lsm303mag_gauss_lsb_xy = 230.0
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self._lsm303mag_gauss_lsb_z = 205.0
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@property
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def mag_rate(self):
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"""The magnetometer update rate."""
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return self._mag_rate
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@mag_rate.setter
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def mag_rate(self, value):
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"""The magnetometer update rate."""
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assert value in (MAGRATE_0_7, MAGRATE_1_5, MAGRATE_3_0, MAGRATE_7_5, MAGRATE_15, MAGRATE_30, MAGRATE_75, MAGRATE_220)
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self._mag_rate = value
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reg_m = ((value & 0x07) << 2) & 0xFF
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self._write_u8(_MAGTYPE, _REG_MAG_CRA_REG_M, reg_m)
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self._write_u8(self._mag_device, _REG_MAG_CRA_REG_M, reg_m)
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def _read_u8(self, sensor_type, address):
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if sensor_type == _ACCELTYPE:
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device = self._accel_device
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else:
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device = self._mag_device
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def _read_u8(self, device, address):
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with device as i2c:
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self._BUFFER[0] = address & 0xFF
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i2c.write(self._BUFFER, end=1, stop=False)
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@ -237,22 +230,14 @@ class LSM303(object):
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return self._BUFFER[0]
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def _read_bytes(self, sensor_type, address, count, buf):
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if sensor_type == _ACCELTYPE:
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device = self._accel_device
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else:
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device = self._mag_device
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def _read_bytes(self, device, address, count, buf):
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with device as i2c:
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buf[0] = address & 0xFF
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i2c.write(buf, end=1, stop=False)
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i2c.readinto(buf, end=count)
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def _write_u8(self, sensor_type, address, val):
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if sensor_type == _ACCELTYPE:
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device = self._accel_device
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else:
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device = self._mag_device
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def _write_u8(self, device, address, val):
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with device as i2c:
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self._BUFFER[0] = address & 0xFF
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self._BUFFER[1] = val & 0xFF
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