initial working version

siddacious · siddacious · commit 499c17bcd36f · 2019-04-16T19:58:03.000-07:00
diff --git a/README.rst b/README.rst
@@ -55,7 +55,7 @@ To install in a virtual environment in your current project:
 Usage Example
 =============
 
-.. todo:: Add a quick, simple example. It and other examples should live in the examples folder and be included in docs/examples.rst.
+See the guide at: https://learn.adafruit.com
 
 Contributing
 ============
diff --git a/adafruit_lps35hw.py b/adafruit_lps35hw.py
@@ -23,7 +23,7 @@
 `adafruit_lps35hw`
 ================================================================================
 
-A driver for the ST LPS35HW water resistant mems pressure sensor
+A driver for the ST LPS35HW water resistant MEMS pressure sensor
 
 
 * Author(s): Bryan Siepert
@@ -36,14 +36,210 @@
 **Software and Dependencies:**
 
  * Adafruit CircuitPython firmware for the supported boards:
-  https://github.com/adafruit/circuitpython/releases
-
-
+    https://github.com/adafruit/circuitpython/releases
  * Adafruit's Bus Device library: https://github.com/adafruit/Adafruit_CircuitPython_BusDevice
  * Adafruit's Register library: https://github.com/adafruit/Adafruit_CircuitPython_Register
+
 """
 
 # imports
 
 __version__ = "0.0.0-auto.0"
 __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_LPS35HW.git"
+
+from micropython import const
+import adafruit_bus_device.i2c_device as i2cdevice
+from adafruit_register.i2c_struct import UnaryStruct
+from adafruit_register.i2c_bits import RWBits, ROBits
+from adafruit_register.i2c_bit import RWBit
+# pylint: disable=bad-whitespace
+_INTERRUPT_CFG	= const(0x0B)
+_THS_P_L	    = const(0x0C)
+_THS_P_H	    = const(0x0D)
+_WHO_AM_I 	    = const(0x0F)
+_CTRL_REG1    	= const(0x10)
+_CTRL_REG2    	= const(0x11)
+_CTRL_REG3    	= const(0x12)
+_FIFO_CTRL    	= const(0x14)
+_REF_P_XL    	= const(0x15)
+_REF_P_L    	= const(0x16)
+_REF_P_H    	= const(0x17)
+_RPDS_L	    	= const(0x18)
+_RPDS_H	    	= const(0x19)
+_RES_CONF    	= const(0x1A)
+_INT_SOURCE	    = const(0x25)
+_FIFO_STATUS	= const(0x26)
+_STATUS		    = const(0x27)
+_PRESS_OUT_XL	= const(0x28)
+_PRESS_OUT_L	= const(0x29)
+_PRESS_OUT_H	= const(0x2A)
+_TEMP_OUT_L 	= const(0x2B)
+_TEMP_OUT_H	    = const(0x2C)
+_LPFP_RES	    = const(0x33)
+# pylint: enable=bad-whitespace
+
+class DataRate: # pylint: disable=too-few-public-methods
+    """Options for ``data_rate``
+
+        +---------------------------+-------------------------+
+        | ``DataRate``              | Time                    |
+        +===========================+=========================+
+        | ``DataRate.ONE_SHOT``     | One shot mode           |
+        +---------------------------+-------------------------+
+        | ``DataRate.RATE_1_hz``    | 1 hz                    |
+        +---------------------------+-------------------------+
+        | ``DataRate.RATE_10_hz``   | 10 hz  (Default)        |
+        +---------------------------+-------------------------+
+        | ``DataRate.RATE_25_hz``   | 25 hz                   |
+        +---------------------------+-------------------------+
+        | ``DataRate.RATE_50_hz``   | 50 hz                   |
+        +---------------------------+-------------------------+
+        | ``DataRate.RATE_75_hz``   | 75 hz                   |
+        +---------------------------+-------------------------+
+
+    """
+    ONE_SHOT = const(0x00)
+    RATE_1_hz = const(0x01)
+    RATE_10_hz = const(0x02)
+    RATE_25_hz = const(0x03)
+    RATE_50_hz = const(0x04)
+    RATE_75_hz = const(0x05)
+
+class LPS35HW:
+    """Driver for the ST LPS35HW MEMS pressure sensor
+
+        :param ~busio.I2C i2c_bus: The I2C bus the INA260 is connected to.
+        :param address: The I2C device address for the sensor. Default is ``0x5d``.
+
+    """
+
+
+    reset_pressure = RWBit(_INTERRUPT_CFG, 4)
+    """Reset ``pressure`` to be reported as the measured absolute value"""
+
+
+    data_rate = RWBits(3, _CTRL_REG1, 4)
+    """The rate at which the sensor measures ``pressure`` and ``temperature``. ``data_rate`` should
+    be set to one of the values of ``adafruit_lps35hw.DataRate``. Note that setting ``data_rate``
+    to ``DataRate.ONE_SHOT`` places the sensor into a low-power shutdown mode where measurements to
+    update ``pressure`` and ``temperature`` are only taken when ``take_measurement`` is called."""
+
+    low_pass_enabled = RWBit(_CTRL_REG1, 3)
+    """True if the low pass filter is enabled. Setting to `True` will reduce the sensor bandwidth
+    from ``data_rate/2`` to ``data_rate/9``, filtering out high-frequency noise."""
+
+    _raw_temperature = ROBits(16, _TEMP_OUT_L, 0, 2)
+    _raw_pressure = ROBits(24, _PRESS_OUT_XL, 0, 3)
+    _reference_pressure = RWBits(24, _REF_P_XL, 0, 3)
+    _pressure_offset = RWBits(16, _RPDS_L, 0, 2)
+
+    _block_updates = RWBit(_CTRL_REG1, 1)
+
+    _reset = RWBit(_CTRL_REG2, 2)
+    _one_shot = RWBit(_CTRL_REG2, 0)
+
+    _interrupt_active_low = RWBit(_CTRL_REG3, 7)
+    _interrupt_open_drain = RWBit(_CTRL_REG3, 6)
+    _int_pin_on_high = RWBit(_CTRL_REG3, 1)
+    _int_pin_on_low = RWBit(_CTRL_REG3, 0)
+
+    _interrupt_active = RWBit(_INT_SOURCE, 2)
+    _pressure_low = RWBit(_INT_SOURCE, 1)
+    _pressure_high = RWBit(_INT_SOURCE, 0)
+
+    _auto_zero = RWBit(_INTERRUPT_CFG, 5)
+    _interrupts_enabled = RWBit(_INTERRUPT_CFG, 3)
+    _interrupt_latch = RWBit(_INTERRUPT_CFG, 2)
+    _interrupt_low = RWBit(_INTERRUPT_CFG, 1)
+    _interrupt_high = RWBit(_INTERRUPT_CFG, 0)
+
+    _reset_filter = ROBits(8, _LPFP_RES, 0, 1)
+
+    _chip_id = UnaryStruct(_WHO_AM_I, "<B")
+    _pressure_threshold = UnaryStruct(_THS_P_L, "<H")
+
+    # def __init__(self, i2c_bus, address=0x5c):
+    def __init__(self, i2c_bus, address=0x5d):
+        self.i2c_device = i2cdevice.I2CDevice(i2c_bus, address)
+        if self._chip_id != 0xb1:
+            raise RuntimeError('Failed to find LPS35HW! Chip ID 0x%x' % self._chip_id)
+
+        self.reset()
+
+        # set data_rate to put the sensor in continuous mode
+        self.data_rate = DataRate.RATE_10_hz
+
+        self._block_updates = True
+        self._interrupt_latch = True
+
+    @property
+    def pressure(self):
+        """The current pressure measurement in hPa"""
+        # reset the filter to prevent spurious readings
+        self._reset_filter # pylint: disable=pointless-statement
+
+        # check for negative and convert
+        raw = self._raw_pressure
+        if raw & (1<<23) != 0:
+            raw = (raw - (1<<24))
+        return raw / 4096.0
+
+    @property
+    def temperature(self):
+        """The current temperature measurement in degrees C"""
+
+        return self._raw_temperature / 100.0
+
+    def reset(self):
+        """Reset the sensor, restoring all configuration registers to their defaults"""
+        self._reset = True
+        # wait for the reset to finish
+        while self._reset:
+            pass
+
+    def take_measurement(self):
+        """Update the value of ``pressure`` and ``temperature`` by taking a single measurement.
+            Only meaningful if ``data_rate`` is set to ``ONE_SHOT``"""
+        self._one_shot = True
+        while self._one_shot:
+            pass
+
+    def zero_pressure(self):
+        """Set the current pressure as zero and report the ``pressure`` relative to it"""
+        self._auto_zero = True
+        while self._auto_zero:
+            pass
+
+    # def reset_pressure(self):
+    #     """Reset ``pressure`` to be reported as the measured absolute value"""
+    #     self._reset_zero = True
+
+    @property
+    def pressure_threshold(self):
+        """The high presure threshold. Use ``high_threshold_enabled`` to use it"""
+        return self._pressure_threshold / 16
+
+    @pressure_threshold.setter
+    def pressure_threshold(self, value):
+        """The high value threshold"""
+        self._pressure_threshold = (value * 16)
+
+    @property
+    def high_threshold_enabled(self):
+        """Set to `True` or `False` to enable or disable the high pressure threshold"""
+        return self._interrupts_enabled and self._interrupt_high
+
+    @high_threshold_enabled.setter
+    def high_threshold_enabled(self, value):
+        if value:
+            self._interrupts_enabled = True
+            self._interrupt_high = True
+        else:
+            self._interrupts_enabled = False
+            self._interrupt_high = False
+
+    @property
+    def high_threshold_exceeded(self):
+        """Returns `True` if the pressure high threshold has been exceeded. Must be enabled by
+        setting ``high_threshold_enabled`` to `True` and setting a ``pressure_threshold``."""
+        return self._pressure_high
diff --git a/docs/conf.py b/docs/conf.py
@@ -20,7 +20,7 @@
 # Uncomment the below if you use native CircuitPython modules such as
 # digitalio, micropython and busio. List the modules you use. Without it, the
 # autodoc module docs will fail to generate with a warning.
-# autodoc_mock_imports = ["digitalio", "busio"]
+autodoc_mock_imports = ["micropython", "adafruit_bus_device", "adafruit_register"]
 
 
 intersphinx_mapping = {'python': ('https://docs.python.org/3.4', None),'BusDevice': ('https://circuitpython.readthedocs.io/projects/busdevice/en/latest/', None),'Register': ('https://circuitpython.readthedocs.io/projects/register/en/latest/', None),'CircuitPython': ('https://circuitpython.readthedocs.io/en/latest/', None)}
diff --git a/examples/lps35hw_data_rate.py b/examples/lps35hw_data_rate.py
@@ -0,0 +1,28 @@
+import board
+from adafruit_lps35hw import LPS35HW, DataRate
+import time
+
+i2c = board.I2C()
+lps = LPS35HW(i2c)
+
+lps.data_rate = DataRate.ONE_SHOT
+lps.take_measurement()
+
+
+while True:
+   print("Pressure: %.2f hPa" % lps.pressure)
+   print("")
+   time.sleep(1)
+   print("Pressure: %.2f hPa" % lps.pressure)
+   print("")
+   time.sleep(1)
+   print("Pressure: %.2f hPa" % lps.pressure)
+   print("")
+   time.sleep(1)
+
+   #take another measurement
+   lps.take_measurement()
+   
+   print("New Pressure: %.2f hPa" % lps.pressure)
+   print("")
+   time.sleep(1)
diff --git a/examples/lps35hw_filter.py b/examples/lps35hw_filter.py
@@ -0,0 +1,12 @@
+import board
+import adafruit_lps35hw
+import time
+
+i2c = board.I2C()
+lps = adafruit_lps35hw.LPS35HW(i2c)
+
+lps.low_pass_enabled = True
+while True:
+   print("Pressure: %.2f hPa" % lps.pressure)
+   print("")
+   time.sleep(0.125)
diff --git a/examples/lps35hw_high_threshold.py b/examples/lps35hw_high_threshold.py
@@ -0,0 +1,17 @@
+import board
+import adafruit_lps35hw
+import time
+i2c = board.I2C()
+lps = adafruit_lps35hw.LPS35HW(i2c)
+
+# You may need to adjust the threshold to something closer
+# to the current pressure where the sensor is
+lps.pressure_threshold = 1030
+
+lps.high_threshold_enabled = True
+
+while True:
+   print("Pressure: %.2f hPa" % lps.pressure)
+   print("Threshhold exceeded: %s" % lps.high_threshold_exceeded)
+   print("")
+   time.sleep(1)
diff --git a/examples/lps35hw_relative.py b/examples/lps35hw_relative.py
@@ -0,0 +1,14 @@
+import board
+import adafruit_lps35hw
+import time
+
+i2c = board.I2C()
+lps = adafruit_lps35hw.LPS35HW(i2c)
+
+# set the current pressure as zero hPa and make measurements
+# relative to that pressure, even negative!
+lps.zero_pressure()
+while True:
+   print("Pressure: %.2f hPa" % lps.pressure)
+   print("")
+   time.sleep(0.5)
diff --git a/examples/lps35hw_simpletest.py b/examples/lps35hw_simpletest.py
@@ -0,0 +1,12 @@
+import board
+import adafruit_lps35hw
+import time
+
+i2c = board.I2C()
+lps = adafruit_lps35hw.LPS35HW(i2c)
+
+while True:
+    print("Pressure: %.2f hPa" % lps.pressure)
+    print("Temperature: %.2f C"% lps.temperature)
+    print("")
+    time.sleep(1)
