added hpf enable

Author: siddacious

adafruit_lis331.py

@@ -51,6 +51,7 @@
 from struct import unpack_from
 from time import sleep
 from adafruit_register.i2c_bits import RWBits
+from adafruit_register.i2c_bit import RWBit
 from adafruit_register.i2c_struct import UnaryStruct, ROUnaryStruct
 import adafruit_bus_device.i2c_device as i2c_device
 
@@ -214,6 +215,7 @@ class RateDivisor(CV):
 
 
 class LIS331:
+    # pylint:disable=too-many-instance-attributes
     """Base class for the LIS331 family of 3-axis accelerometers.
     **Cannot be instantiated directly**
 
@@ -229,6 +231,12 @@ class LIS331:
     _range_bits = RWBits(2, _LIS331_REG_CTRL4, 4)
     _raw_acceleration = ROByteArray((_LIS331_REG_OUT_X_L | 0x80), "<hhh", 6)
     _reference_value = UnaryStruct(_LIS331_REG_REFERENCE, "<b")
+    _zero_hpf_reference = ROUnaryStruct(_LIS331_REG_HP_FILTER_RESET, "<b")
+
+    _hpf_mode_bits = RWBit(_LIS331_REG_CTRL2, 5)
+    _hpf_enable_bit = RWBit(_LIS331_REG_CTRL2, 4)
+    _hpf_cutoff = RWBits(2, _LIS331_REG_CTRL2, 0)
+
     CHIP_ID = None
     #           Adafruit_BusIO_Register reference_reg = Adafruit_BusIO_Register(
     #       i2c_dev, spi_dev, ADDRBIT8_HIGH_TOREAD, LIS331_REG_REFERENCE);
@@ -244,6 +252,7 @@ def __init__(self, i2c_bus, address=_LIS331_DEFAULT_ADDRESS):
                 "Failed to find %s - check your wiring!" % self.__class__.__name__
             )
         self._range_class = None
+        self.enable_hpf(False)
 
     @property
     def lpf_cutoff(self):
@@ -293,12 +302,32 @@ def hpf_reference(self, reference_value):
             raise AttributeError("`hpf_reference` must be from -128 to 127")
         self._reference_value = reference_value
 
-    #   void enableHighPassFilter(bool filter_enabled,
-    #                             lis331_hpf_cutoff_t cutoff = LIS331_HPF_0_0025_ODR,
-    #                             bool use_reference = false);
-    #   void setHPFReference(int8_t reference);
-    #   int8_t getHPFReference(void);
-    #   void HPFReset(void);
+    def zero_hpf(self):
+        """When the high-pass filter is enabled  with ``use_reference=False``, calling ``zero_hpf``
+        will set all measurements to zero immediately, avoiding the normal settling time seen when
+        using the high-pass filter without a ``hpf_reference``
+        """
+
+    def enable_hpf(
+        self, enabled=True, cutoff=RateDivisor.ODR_DIV_50, use_reference=False
+    ):  # pylint: disable=no-member
+        """Enable or disable the high-pass filter.
+
+        :param enabled: Enable or disable the filter. Default is `True` to enable
+        :param ~RateDivisor cutoff: A `RateDivisor` to set the high-pass cutoff frequency. Default\
+        is ``RateDivisor.ODR_DIV_50``. See ``RateDivisor`` for more information
+        :param use_reference: Determines if the filtered measurements are offset by a reference\
+        value. Default is false.
+
+    See section **4** of the LIS331DLH application note for more information `LIS331DLH application\
+        note for more information <https://www.st.com/content/ccc/resource/technical/document/\
+        application_note/b5/8e/58/69/cb/87/45/55/CD00215823.pdf/files/CD00215823.pdf/jcr:content/\
+        translations/en.CD00215823.pdf>`_
+
+        """
+        self._hpf_mode_bits = use_reference
+        self._hpf_cutoff = cutoff
+        self._hpf_enable_bit = enabled
 
     @property
     def data_rate(self):

examples/lis331_filter_test.py

@@ -8,11 +8,12 @@
 # lis = H3LIS331(i2c)
 lis = LIS331HH(i2c)
 
+# `data_rate` must be a `LOWPOWER` rate to use the low-pass filter
 lis.data_rate = Rate.RATE_LOWPOWER_10_HZ
 print("Rate is %sHz" % Rate.string[lis.data_rate])
 
-lis.lpf_cutoff = Frequency.FREQ_37_HZ
-print("LPF cutoff frequency is %sHz" % Frequency.string[lis.lpf_cutoff])
+# lis.lpf_cutoff = Frequency.FREQ_37_HZ
+# print("LPF cutoff frequency is %sHz" % Frequency.string[lis.lpf_cutoff])
 
 # un-comment the range for the sensor you are using
 # lis.range = H3LIS331Range.RANGE_100G
@@ -21,6 +22,11 @@
 range_string = LIS331HHRange.string[lis.range]
 print("Range is +/-%sg" % range_string)
 
+lis.hpf_reference = 127
+print("high-pass filter reference value:", lis.hpf_reference)
+
+lis.enable_hpf(True)
 while True:
     print(lis.acceleration)  # plotter friendly printing
-    time.sleep(0.005)
+    # print((lis.acceleration[2],))  # plotter friendly printing
+    time.sleep(0.2)