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BM390 sample, by Adafruit

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# SPDX-FileCopyrightText: 2018 Carter Nelson for Adafruit Industries
#
# SPDX-License-Identifier: MIT
"""
`adafruit_bmp3xx`
====================================================
CircuitPython driver from BMP388 Temperature and Barometric Pressure sensor.
* Author(s): Carter Nelson
Implementation Notes
--------------------
**Hardware:**
* `Adafruit BMP388 - Precision Barometric Pressure and Altimeter
<https://www.adafruit.com/product/3966>`_ (Product ID: 3966)
**Software and Dependencies:**
* Adafruit CircuitPython firmware for the supported boards:
https://circuitpython.org/downloads
* Adafruit's Bus Device library:
https://github.com/adafruit/Adafruit_CircuitPython_BusDevice
"""
import struct
import time
# from micropython import const
def const(x): return x
__version__ = "0.0.0-auto.0"
__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_BMP3XX.git"
_BMP388_CHIP_ID = const(0x50)
_BMP390_CHIP_ID = const(0x60)
# pylint: disable=import-outside-toplevel
_REGISTER_CHIPID = const(0x00)
_REGISTER_STATUS = const(0x03)
_REGISTER_PRESSUREDATA = const(0x04)
_REGISTER_TEMPDATA = const(0x07)
_REGISTER_CONTROL = const(0x1B)
_REGISTER_OSR = const(0x1C)
_REGISTER_ODR = const(0x1D)
_REGISTER_CONFIG = const(0x1F)
_REGISTER_CAL_DATA = const(0x31)
_REGISTER_CMD = const(0x7E)
_OSR_SETTINGS = (1, 2, 4, 8, 16, 32) # pressure and temperature oversampling settings
_IIR_SETTINGS = (0, 2, 4, 8, 16, 32, 64, 128) # IIR filter coefficients
class BMP3XX:
"""Base class for BMP3XX sensor."""
def __init__(self):
chip_id = self._read_byte(_REGISTER_CHIPID)
if chip_id not in (_BMP388_CHIP_ID, _BMP390_CHIP_ID):
raise RuntimeError("Failed to find BMP3XX! Chip ID 0x%x" % chip_id)
self._read_coefficients()
self.reset()
self.sea_level_pressure = 1013.25
self._wait_time = 0.002 # change this value to have faster reads if needed
"""Sea level pressure in hPa."""
@property
def pressure(self):
"""The pressure in hPa."""
return self._read()[0] / 100
@property
def temperature(self):
"""The temperature in degrees Celsius"""
return self._read()[1]
@property
def altitude(self):
"""The altitude in meters based on the currently set sea level pressure."""
# see https://www.weather.gov/media/epz/wxcalc/pressureAltitude.pdf
return 44307.7 * (1 - (self.pressure / self.sea_level_pressure) ** 0.190284)
@property
def pressure_oversampling(self):
"""The pressure oversampling setting."""
return _OSR_SETTINGS[self._read_byte(_REGISTER_OSR) & 0x07]
@pressure_oversampling.setter
def pressure_oversampling(self, oversample):
if oversample not in _OSR_SETTINGS:
raise ValueError("Oversampling must be one of: {}".format(_OSR_SETTINGS))
new_setting = self._read_byte(_REGISTER_OSR) & 0xF8 | _OSR_SETTINGS.index(
oversample
)
self._write_register_byte(_REGISTER_OSR, new_setting)
@property
def temperature_oversampling(self):
"""The temperature oversampling setting."""
return _OSR_SETTINGS[self._read_byte(_REGISTER_OSR) >> 3 & 0x07]
@temperature_oversampling.setter
def temperature_oversampling(self, oversample):
if oversample not in _OSR_SETTINGS:
raise ValueError("Oversampling must be one of: {}".format(_OSR_SETTINGS))
new_setting = (
self._read_byte(_REGISTER_OSR) & 0xC7 | _OSR_SETTINGS.index(oversample) << 3
)
self._write_register_byte(_REGISTER_OSR, new_setting)
@property
def filter_coefficient(self):
"""The IIR filter coefficient."""
return _IIR_SETTINGS[self._read_byte(_REGISTER_CONFIG) >> 1 & 0x07]
@filter_coefficient.setter
def filter_coefficient(self, coef):
if coef not in _IIR_SETTINGS:
raise ValueError(
"Filter coefficient must be one of: {}".format(_IIR_SETTINGS)
)
self._write_register_byte(_REGISTER_CONFIG, _IIR_SETTINGS.index(coef) << 1)
def reset(self):
"""Perform a power on reset. All user configuration settings are overwritten
with their default state.
"""
self._write_register_byte(_REGISTER_CMD, 0xB6)
def _read(self):
"""Returns a tuple for temperature and pressure."""
# OK, pylint. This one is all kinds of stuff you shouldn't worry about.
# pylint: disable=invalid-name, too-many-locals
# Perform one measurement in forced mode
self._write_register_byte(_REGISTER_CONTROL, 0x13)
# Wait for *both* conversions to complete
while self._read_byte(_REGISTER_STATUS) & 0x60 != 0x60:
time.sleep(self._wait_time)
# Get ADC values
data = self._read_register(_REGISTER_PRESSUREDATA, 6)
adc_p = data[2] << 16 | data[1] << 8 | data[0]
adc_t = data[5] << 16 | data[4] << 8 | data[3]
# datasheet, sec 9.2 Temperature compensation
T1, T2, T3 = self._temp_calib
pd1 = adc_t - T1
pd2 = pd1 * T2
temperature = pd2 + (pd1 * pd1) * T3
# datasheet, sec 9.3 Pressure compensation
P1, P2, P3, P4, P5, P6, P7, P8, P9, P10, P11 = self._pressure_calib
pd1 = P6 * temperature
pd2 = P7 * temperature ** 2.0
pd3 = P8 * temperature ** 3.0
po1 = P5 + pd1 + pd2 + pd3
pd1 = P2 * temperature
pd2 = P3 * temperature ** 2.0
pd3 = P4 * temperature ** 3.0
po2 = adc_p * (P1 + pd1 + pd2 + pd3)
pd1 = adc_p ** 2.0
pd2 = P9 + P10 * temperature
pd3 = pd1 * pd2
pd4 = pd3 + P11 * adc_p ** 3.0
pressure = po1 + po2 + pd4
# pressure in hPa, temperature in deg C
return pressure, temperature
def _read_coefficients(self):
"""Read & save the calibration coefficients"""
coeff = self._read_register(_REGISTER_CAL_DATA, 21)
# See datasheet, pg. 27, table 22
coeff = struct.unpack("<HHbhhbbHHbbhbb", coeff)
# See datasheet, sec 9.1
# Note: forcing float math to prevent issues with boards that
# do not support long ints for 2**<large int>
self._temp_calib = (
coeff[0] / 2 ** -8.0, # T1
coeff[1] / 2 ** 30.0, # T2
coeff[2] / 2 ** 48.0,
) # T3
self._pressure_calib = (
(coeff[3] - 2 ** 14.0) / 2 ** 20.0, # P1
(coeff[4] - 2 ** 14.0) / 2 ** 29.0, # P2
coeff[5] / 2 ** 32.0, # P3
coeff[6] / 2 ** 37.0, # P4
coeff[7] / 2 ** -3.0, # P5
coeff[8] / 2 ** 6.0, # P6
coeff[9] / 2 ** 8.0, # P7
coeff[10] / 2 ** 15.0, # P8
coeff[11] / 2 ** 48.0, # P9
coeff[12] / 2 ** 48.0, # P10
coeff[13] / 2 ** 65.0,
) # P11
def _read_byte(self, register):
"""Read a byte register value and return it"""
return self._read_register(register, 1)[0]
def _read_register(self, register, length):
"""Low level register reading, not implemented in base class"""
raise NotImplementedError()
def _write_register_byte(self, register, value):
"""Low level register writing, not implemented in base class"""
raise NotImplementedError()
class BMP3XX_I2C(BMP3XX):
"""Driver for I2C connected BMP3XX.
:param ~busio.I2C i2c: The I2C bus the BMP388 is connected to.
:param int address: I2C device address. Defaults to :const:`0x77`.
but another address can be passed in as an argument
**Quickstart: Importing and using the BMP388**
Here is an example of using the :class:`BMP3XX_I2C` class.
First you will need to import the libraries to use the sensor
.. code-block:: python
import board
import adafruit_bmp3xx
Once this is done you can define your `board.I2C` object and define your sensor object
.. code-block:: python
i2c = board.I2C() # uses board.SCL and board.SDA
bmp = adafruit_bmp3xx.BMP3XX_I2C(i2c)
Now you have access to the :attr:`temperature` and :attr:`pressure` attributes
.. code-block:: python
temperature = bmp.temperature
pressure = bmp.pressure
"""
def __init__(self, i2c, address=0x77):
from adafruit_bus_device import i2c_device
self._i2c = i2c_device.I2CDevice(i2c, address)
super().__init__()
def _read_register(self, register, length):
"""Low level register reading over I2C, returns a list of values"""
result = bytearray(length)
with self._i2c as i2c:
i2c.write(bytes([register & 0xFF]))
i2c.readinto(result)
return result
def _write_register_byte(self, register, value):
"""Low level register writing over I2C, writes one 8-bit value"""
with self._i2c as i2c:
i2c.write(bytes((register & 0xFF, value & 0xFF)))
class BMP3XX_SPI(BMP3XX):
"""Driver for SPI connected BMP3XX.
:param ~busio.SPI spi: SPI device
:param ~digitalio.DigitalInOut cs: Chip Select
**Quickstart: Importing and using the BMP388**
Here is an example of using the :class:`BMP3XX_SPI` class.
First you will need to import the libraries to use the sensor
.. code-block:: python
import board
import adafruit_bmp3xx
from digitalio import DigitalInOut, Direction
Once this is done you can define your `board.SPI` object and define your sensor object
.. code-block:: python
spi = board.SPI()
cs = DigitalInOut(board.D5)
bmp = adafruit_bmp3xx.BMP3XX_SPI(spi, cs)
Now you have access to the :attr:`temperature` and :attr:`pressure` attributes
.. code-block:: python
temperature = bmp.temperature
pressure = bmp.pressure
"""
def __init__(self, spi, cs):
from adafruit_bus_device import spi_device
self._spi = spi_device.SPIDevice(spi, cs)
# toggle CS low/high to put BMP3XX in SPI mode
with self._spi:
time.sleep(0.001)
super().__init__()
def _read_register(self, register, length):
"""Low level register reading over SPI, returns a list of values"""
result = bytearray(length)
with self._spi as spi:
# pylint: disable=no-member
spi.write(bytes((0x80 | register, 0x00)))
spi.readinto(result)
return result
def _write_register_byte(self, register, value):
"""Low level register writing over SPI, writes one 8-bit value"""
with self._spi as spi:
# pylint: disable=no-member
spi.write(bytes((register & 0x7F, value & 0xFF)))
#
from i2cdriver import I2CDriver
import sys
class BMP3XX_I2CDriver(BMP3XX):
"""Driver for I2CDriver connected BMP3XX.
:param ~busio.I2C i2c: The I2CDriver the BMP388 is connected to.
:param int address: I2C device address. Defaults to :const:`0x77`.
but another address can be passed in as an argument
**Quickstart: Importing and using the BMP388**
Here is an example of using the :class:`BMP3XX_I2CDriver` class.
First you will need to import the libraries
.. code-block:: python
from i2cdriver import I2CDriver
import adafruit_bmp3xx
Once this is done you can connect to the I2CDriver and define the sensor object, e.g.
.. code-block:: python
i2c = I2CDriver("COM9")
bmp = adafruit_bmp3xx.BMP3XX_I2C(i2c)
Now you have access to the :attr:`temperature` and :attr:`pressure` attributes
.. code-block:: python
temperature = bmp.temperature
pressure = bmp.pressure
"""
def __init__(self, i2c, address=0x77):
self.i2c = i2c
self.a = address
super().__init__()
def _read_register(self, register, length):
"""Low level register reading over I2C, returns a list of values"""
return self.i2c.regrd(self.a, register, length)
def _write_register_byte(self, register, value):
"""Low level register writing over I2C, writes one 8-bit value"""
self.i2c.regwr(self.a, register, value)
if __name__ == '__main__':
i2 = I2CDriver(sys.argv[1])
d = BMP3XX_I2CDriver(i2)
d.pressure_oversampling = 32
d.temperature_oversampling = 32
while 1:
(pressure, temperature) = d._read()
print(f"Pressure: {pressure / 100:.2f} hPa")
print(f"Temperature: {temperature:.2f} C")