From ecf5d5460b4c0c8da99a4561011bc23cd5413e4d Mon Sep 17 00:00:00 2001
From: Ryan Pavlik <ryan.pavlik@collabora.com>
Date: Tue, 16 Mar 2021 13:08:00 -0500
Subject: [PATCH 01/12] Fix LUT

---
 adafruit_emc2101.py | 37 ++++++-------------------------------
 1 file changed, 6 insertions(+), 31 deletions(-)

diff --git a/adafruit_emc2101.py b/adafruit_emc2101.py
index 3ed3002..1dcbfa1 100644
--- a/adafruit_emc2101.py
+++ b/adafruit_emc2101.py
@@ -102,27 +102,6 @@ class FanSpeedLUT:
     _fan_lut_t8 = UnaryStruct(0x5E, "<B")
     _fan_lut_s8 = UnaryStruct(0x5F, "<B")
 
-    _lut_speed_setters = [
-        _fan_lut_s1,
-        _fan_lut_s2,
-        _fan_lut_s3,
-        _fan_lut_s4,
-        _fan_lut_s5,
-        _fan_lut_s6,
-        _fan_lut_s7,
-        _fan_lut_s8,
-    ]
-    _lut_temp_setters = [
-        _fan_lut_t1,
-        _fan_lut_t2,
-        _fan_lut_t3,
-        _fan_lut_t4,
-        _fan_lut_t5,
-        _fan_lut_t6,
-        _fan_lut_t7,
-        _fan_lut_t8,
-    ]
-
     def __init__(self, fan_obj):
         self.emc_fan = fan_obj
         self.lut_values = {}
@@ -187,19 +166,15 @@ def _set_lut(self, lut_dict):
         # get and sort the new lut keys so that we can assign them in order
         lut_keys = list(self.lut_values.keys())
         lut_keys.sort()
-        for idx in range(lut_size):
-            current_temp = lut_keys[idx]
+        for idx, current_temp in enumerate(sorted(self.lut_values.keys())):
             current_speed = _speed_to_lsb(self.lut_values[current_temp])
-            getattr(self, "_fan_lut_t%d" % (idx + 1)).__set__(self, current_temp)
-            getattr(self, "_fan_lut_s%d" % (idx + 1)).__set__(self, current_speed)
-
-            # self.emc_fan._lut_temp_setters[idx].__set__(self.emc_fan, current_temp)
-            # self.emc_fan._lut_speed_setters[idx].__set__(self.emc_fan, current_speed)
+            setattr(self, "_fan_lut_t%d" % (idx + 1), current_temp)
+            setattr(self, "_fan_lut_s%d" % (idx + 1), current_speed)
 
         # Set the remaining LUT entries to the default (Temp/Speed = max value)
-        for idx in range(8)[lut_size:]:
-            getattr(self, "_fan_lut_t%d" % (idx + 1)).__set__(self, MAX_LUT_TEMP)
-            getattr(self, "_fan_lut_s%d" % (idx + 1)).__set__(self, MAX_LUT_SPEED)
+        for idx in range(8)[len(self.lut_values) :]:
+            setattr(self, "_fan_lut_t%d" % (idx + 1), MAX_LUT_TEMP)
+            setattr(self, "_fan_lut_s%d" % (idx + 1), MAX_LUT_SPEED)
         self.emc_fan.lut_enabled = current_mode
 
 

From f7b2b73f944425de0db65bf3d45417237e802a4a Mon Sep 17 00:00:00 2001
From: Ryan Pavlik <ryan.pavlik@gmail.com>
Date: Sun, 14 Mar 2021 12:43:48 -0500
Subject: [PATCH 02/12] Split file for low mem like samd21, and slightly
 improve LUT code

---
 .../__init__.py                               | 190 --------------
 adafruit_emc2101/emc2101_lut.py               | 238 ++++++++++++++++++
 examples/emc2101_lut_example.py               |   4 +-
 examples/set_pwm_freq.py                      |   4 +-
 4 files changed, 242 insertions(+), 194 deletions(-)
 rename adafruit_emc2101.py => adafruit_emc2101/__init__.py (57%)
 create mode 100644 adafruit_emc2101/emc2101_lut.py

diff --git a/adafruit_emc2101.py b/adafruit_emc2101/__init__.py
similarity index 57%
rename from adafruit_emc2101.py
rename to adafruit_emc2101/__init__.py
index 1dcbfa1..24df5ec 100644
--- a/adafruit_emc2101.py
+++ b/adafruit_emc2101/__init__.py
@@ -39,7 +39,6 @@
 _EXTERNAL_TEMP_MSB = const(0x01)
 _EXTERNAL_TEMP_LSB = const(0x10)
 
-_STATUS = const(0x02)
 _REG_CONFIG = const(0x03)
 _TEMP_FORCE = const(0x0C)
 _TACH_LSB = const(0x46)
@@ -49,11 +48,7 @@
 _FAN_CONFIG = const(0x4A)
 _FAN_SPINUP = const(0x4B)
 _REG_FAN_SETTING = const(0x4C)
-_PWM_FREQ = const(0x4D)
-_PWM_DIV = const(0x4E)
-_LUT_HYSTERESIS = const(0x4F)
 
-_TEMP_FILTER = const(0xBF)
 _REG_PARTID = const(0xFD)  # 0x16
 _REG_MFGID = const(0xFE)  # 0xFF16
 
@@ -62,120 +57,6 @@
 
 _I2C_ADDR = const(0x4C)
 _FAN_RPM_DIVISOR = const(5400000)
-_TEMP_LSB = 0.125
-
-
-def _speed_to_lsb(percentage):
-    return round((percentage / 100.0) * MAX_LUT_SPEED)
-
-
-def _lsb_to_speed(lsb_speed):
-    return round((lsb_speed / MAX_LUT_SPEED) * 100.0)
-
-
-class FanSpeedLUT:
-    """A class used to provide a dict-like interface to the EMC2101's Temperature to Fan speed
-    Look Up Table"""
-
-    # seems like a pain but ¯\_(ツ)_/¯
-    _fan_lut_t1 = UnaryStruct(0x50, "<B")
-    _fan_lut_s1 = UnaryStruct(0x51, "<B")
-
-    _fan_lut_t2 = UnaryStruct(0x52, "<B")
-    _fan_lut_s2 = UnaryStruct(0x53, "<B")
-
-    _fan_lut_t3 = UnaryStruct(0x54, "<B")
-    _fan_lut_s3 = UnaryStruct(0x55, "<B")
-
-    _fan_lut_t4 = UnaryStruct(0x56, "<B")
-    _fan_lut_s4 = UnaryStruct(0x57, "<B")
-
-    _fan_lut_t5 = UnaryStruct(0x58, "<B")
-    _fan_lut_s5 = UnaryStruct(0x59, "<B")
-
-    _fan_lut_t6 = UnaryStruct(0x5A, "<B")
-    _fan_lut_s6 = UnaryStruct(0x5B, "<B")
-
-    _fan_lut_t7 = UnaryStruct(0x5C, "<B")
-    _fan_lut_s7 = UnaryStruct(0x5D, "<B")
-
-    _fan_lut_t8 = UnaryStruct(0x5E, "<B")
-    _fan_lut_s8 = UnaryStruct(0x5F, "<B")
-
-    def __init__(self, fan_obj):
-        self.emc_fan = fan_obj
-        self.lut_values = {}
-        self.i2c_device = fan_obj.i2c_device
-
-    def __getitem__(self, index):
-        if not isinstance(index, int):
-            raise IndexError
-        if not index in self.lut_values:
-            raise IndexError
-        return self.lut_values[index]
-
-    def __setitem__(self, index, value):
-        if not isinstance(index, int):
-            raise IndexError
-        self.lut_values[index] = value
-        self._set_lut(self.lut_values)
-
-    def __repr__(self):
-        """return the official string representation of the LUT"""
-        return "FanSpeedLUT <%x>" % id(self)
-
-    def __str__(self):
-        """return the official string representation of the LUT"""
-        value_strs = []
-        lut_keys = list(self.lut_values.keys())
-        lut_keys.sort()
-        for temp in lut_keys:
-            fan_drive = self.lut_values[temp]
-            value_strs.append("%d deg C => %.1f%% duty cycle" % (temp, fan_drive))
-
-        return "\n".join(value_strs)
-
-    def __len__(self):
-        return len(self.lut_values)
-
-    # this function does a whole lot of work to organized the user-supplied lut dict into
-    # their correct spot within the lut table as pairs of set registers, sorted with the lowest
-    # temperature first
-
-    def _set_lut(self, lut_dict):
-        lut_keys = list(lut_dict.keys())
-        lut_size = len(lut_dict)
-        # Make sure we're not going to try to set more entries than we have slots
-        if lut_size > 8:
-            raise AttributeError("LUT can only contain a maximum of 8 items")
-
-        # we want to assign the lowest temperature to the lowest LUT slot, so we sort the keys/temps
-        for k in lut_keys:
-            # Verify that the value is a correct amount
-            lut_value = lut_dict[k]
-            if lut_value > 100.0 or lut_value < 0:
-                raise AttributeError("LUT values must be a fan speed from 0-100%")
-
-            # add the current temp/speed to our internal representation
-            self.lut_values[k] = lut_value
-        current_mode = self.emc_fan.lut_enabled
-
-        # Disable the lut to allow it to be updated
-        self.emc_fan.lut_enabled = False
-
-        # get and sort the new lut keys so that we can assign them in order
-        lut_keys = list(self.lut_values.keys())
-        lut_keys.sort()
-        for idx, current_temp in enumerate(sorted(self.lut_values.keys())):
-            current_speed = _speed_to_lsb(self.lut_values[current_temp])
-            setattr(self, "_fan_lut_t%d" % (idx + 1), current_temp)
-            setattr(self, "_fan_lut_s%d" % (idx + 1), current_speed)
-
-        # Set the remaining LUT entries to the default (Temp/Speed = max value)
-        for idx in range(8)[len(self.lut_values) :]:
-            setattr(self, "_fan_lut_t%d" % (idx + 1), MAX_LUT_TEMP)
-            setattr(self, "_fan_lut_s%d" % (idx + 1), MAX_LUT_SPEED)
-        self.emc_fan.lut_enabled = current_mode
 
 
 class CV:
@@ -285,11 +166,6 @@ class EMC2101:  # pylint: disable=too-many-instance-attributes
     """When set to True, the magnitude of the fan output signal is inverted, making 0 the maximum
     value and 100 the minimum value"""
 
-    _fan_pwm_clock_select = RWBit(_FAN_CONFIG, 3)
-    _fan_pwm_clock_override = RWBit(_FAN_CONFIG, 2)
-    _pwm_freq = RWBits(5, _PWM_FREQ, 0)
-    _pwm_freq_div = UnaryStruct(_PWM_DIV, "<B")
-
     dac_output_enabled = RWBit(_REG_CONFIG, 4)
     """When set, the fan control signal is output as a DC voltage instead of a PWM signal"""
 
@@ -299,27 +175,18 @@ class EMC2101:  # pylint: disable=too-many-instance-attributes
     _spin_time = RWBits(3, _FAN_SPINUP, 0)
     _spin_tach_limit = RWBit(_FAN_SPINUP, 5)
 
-    lut_temperature_hysteresis = UnaryStruct(_LUT_HYSTERESIS, "<B")
-    """The amount of hysteresis in Degrees celcius of hysteresis applied to temperature readings
-    used for the LUT. As the temperature drops, the controller will switch to a lower LUT entry when
-    the measured value is belowthe lower entry's threshold, minus the hysteresis value"""
-
     def __init__(self, i2c_bus):
         self.i2c_device = i2cdevice.I2CDevice(i2c_bus, _I2C_ADDR)
 
         if not self._part_id in [0x16, 0x28] or self._mfg_id != 0x5D:
             raise AttributeError("Cannot find a EMC2101")
-        # self._lut = {}
 
         self.initialize()
-        self._lut = FanSpeedLUT(self)
 
     def initialize(self):
         """Reset the controller to an initial default configuration"""
         self._tach_mode_enable = True
-        self.lut_enabled = False
         self._enabled_forced_temp = False
-        self._fan_pwm_clock_override = True
         self._spin_tach_limit = False
 
     @property
@@ -339,54 +206,6 @@ def external_temperature(self):
 
         return full_tmp
 
-    def set_pwm_clock(self, use_preset=False, use_slow=False):
-        """
-             Select the PWM clock source, chosing between two preset clocks or by configuring the
-             clock using `pwm_frequency` and `pwm_frequency_divisor`.
-
-        :param bool use_preset:
-         True: Select between two preset clock sources
-         False: The PWM clock is set by `pwm_frequency` and `pwm_frequency_divisor`
-        :param bool use_slow:
-             True: Use the 1.4kHz clock
-             False: Use the 360kHz clock.
-        :type priority: integer or None
-        :return: None
-        :raises AttributeError: if use_preset is not a `bool`
-        :raises AttributeError: if use_slow is not a `bool`
-
-        """
-
-        if not isinstance(use_preset, bool):
-            raise AttributeError("use_preset must be given a bool")
-        if not isinstance(use_slow, bool):
-            raise AttributeError("use_slow_pwm must be given a bool")
-
-        self._fan_pwm_clock_override = not use_preset
-        self._fan_pwm_clock_select = use_slow
-
-    @property
-    def pwm_frequency(self):
-        """Selects the base clock frequency used for the fan PWM output"""
-        return self._pwm_freq
-
-    @pwm_frequency.setter
-    def pwm_frequency(self, value):
-        if value < 0 or value > 0x1F:
-            raise AttributeError("pwm_frequency must be from 0-31")
-        self._pwm_freq = value
-
-    @property
-    def pwm_frequency_divisor(self):
-        """The Divisor applied to the PWM frequency to set the final frequency"""
-        return self._pwm_freq_div
-
-    @pwm_frequency_divisor.setter
-    def pwm_frequency_divisor(self, divisor):
-        if divisor < 0 or divisor > 255:
-            raise AttributeError("pwm_frequency_divisor must be from 0-255")
-        self._pwm_freq_div = divisor
-
     @property
     def fan_speed(self):
         """The current speed in Revolutions per Minute (RPM)"""
@@ -422,15 +241,6 @@ def lut_enabled(self):
         to a fan speed. When the LUT is disabled fan speed can be changed with `manual_fan_speed`"""
         return not self._fan_lut_prog
 
-    @lut_enabled.setter
-    def lut_enabled(self, enable_lut):
-        self._fan_lut_prog = not enable_lut
-
-    @property
-    def lut(self):
-        """The dict-like representation of the LUT"""
-        return self._lut
-
     @property
     def tach_limit(self):
         """The maximum /minimum speed expected for the fan"""
diff --git a/adafruit_emc2101/emc2101_lut.py b/adafruit_emc2101/emc2101_lut.py
new file mode 100644
index 0000000..4a818d8
--- /dev/null
+++ b/adafruit_emc2101/emc2101_lut.py
@@ -0,0 +1,238 @@
+# SPDX-FileCopyrightText: Copyright (c) 2020 Bryan Siepert for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
+"""
+`adafruit_emc2101.emc2101_lut`
+================================================================================
+
+Brushless fan controller: extended functionality
+
+
+* Author(s): Bryan Siepert
+
+Implementation Notes
+--------------------
+
+**Hardware:**
+
+* `Adafruit EMC2101 Breakout <https://adafruit.com/product/4808>`_
+
+**Software and Dependencies:**
+
+* Adafruit CircuitPython firmware for the supported boards:
+  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
+
+The class defined here may be used instead of adafruit_emc2101.EMC2101,
+if your device has enough RAM to support it. This class adds LUT control
+and PWM frequency control to the base feature set.
+"""
+
+from micropython import const
+from adafruit_register.i2c_struct import UnaryStruct
+from adafruit_register.i2c_bit import RWBit
+from adafruit_register.i2c_bits import RWBits
+from . import EMC2101
+
+__version__ = "0.0.0-auto.0"
+__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_EMC2101.git"
+
+_FAN_CONFIG = const(0x4A)
+_PWM_FREQ = const(0x4D)
+_PWM_DIV = const(0x4E)
+_LUT_HYSTERESIS = const(0x4F)
+
+MAX_LUT_SPEED = 0x3F  # 6-bit value
+MAX_LUT_TEMP = 0x7F  # 7-bit
+
+
+def _speed_to_lsb(percentage):
+    return round((percentage / 100.0) * MAX_LUT_SPEED)
+
+
+class FanSpeedLUT:
+    """A class used to provide a dict-like interface to the EMC2101's Temperature to Fan speed
+    Look Up Table"""
+
+    # seems like a pain but ¯\_(ツ)_/¯
+    _fan_lut_t1 = UnaryStruct(0x50, "<B")
+    _fan_lut_s1 = UnaryStruct(0x51, "<B")
+
+    _fan_lut_t2 = UnaryStruct(0x52, "<B")
+    _fan_lut_s2 = UnaryStruct(0x53, "<B")
+
+    _fan_lut_t3 = UnaryStruct(0x54, "<B")
+    _fan_lut_s3 = UnaryStruct(0x55, "<B")
+
+    _fan_lut_t4 = UnaryStruct(0x56, "<B")
+    _fan_lut_s4 = UnaryStruct(0x57, "<B")
+
+    _fan_lut_t5 = UnaryStruct(0x58, "<B")
+    _fan_lut_s5 = UnaryStruct(0x59, "<B")
+
+    _fan_lut_t6 = UnaryStruct(0x5A, "<B")
+    _fan_lut_s6 = UnaryStruct(0x5B, "<B")
+
+    _fan_lut_t7 = UnaryStruct(0x5C, "<B")
+    _fan_lut_s7 = UnaryStruct(0x5D, "<B")
+
+    _fan_lut_t8 = UnaryStruct(0x5E, "<B")
+    _fan_lut_s8 = UnaryStruct(0x5F, "<B")
+
+    def __init__(self, fan_obj):
+        self.emc_fan = fan_obj
+        self.lut_values = {}
+        self.i2c_device = fan_obj.i2c_device
+
+    def __getitem__(self, index):
+        if not isinstance(index, int):
+            raise IndexError
+        if not index in self.lut_values:
+            raise IndexError
+        return self.lut_values[index]
+
+    def __setitem__(self, index, value):
+        if not isinstance(index, int):
+            raise IndexError
+        if value > 100.0 or value < 0:
+            raise AttributeError("LUT values must be a fan speed from 0-100%")
+        self.lut_values[index] = value
+        self._update_lut()
+
+    def __repr__(self):
+        """return the official string representation of the LUT"""
+        return "FanSpeedLUT <%x>" % id(self)
+
+    def __str__(self):
+        """return the official string representation of the LUT"""
+        value_strs = []
+        lut_keys = list(sorted(self.lut_values.keys()))
+        for temp in lut_keys:
+            fan_drive = self.lut_values[temp]
+            value_strs.append("%d deg C => %.1f%% duty cycle" % (temp, fan_drive))
+
+        return "\n".join(value_strs)
+
+    def __len__(self):
+        return len(self.lut_values)
+
+    # this function does a whole lot of work to organized the user-supplied lut dict into
+    # their correct spot within the lut table as pairs of set registers, sorted with the lowest
+    # temperature first
+
+    def _update_lut(self):
+        # Make sure we're not going to try to set more entries than we have slots
+        if len(self.lut_values) > 8:
+            raise AttributeError("LUT can only contain a maximum of 8 items")
+
+        # Backup state
+        current_mode = self.emc_fan.lut_enabled
+
+        # Disable the lut to allow it to be updated
+        self.emc_fan.lut_enabled = False
+
+        # we want to assign the lowest temperature to the lowest LUT slot, so we sort the keys/temps
+        # get and sort the new lut keys so that we can assign them in order
+        for idx, current_temp in enumerate(sorted(self.lut_values.keys())):
+            current_speed = _speed_to_lsb(self.lut_values[current_temp])
+            setattr(self, "_fan_lut_t%d" % (idx + 1), current_temp)
+            setattr(self, "_fan_lut_s%d" % (idx + 1), current_speed)
+
+        # Set the remaining LUT entries to the default (Temp/Speed = max value)
+        for idx in range(8)[len(self.lut_values) :]:
+            setattr(self, "_fan_lut_t%d" % (idx + 1), MAX_LUT_TEMP)
+            setattr(self, "_fan_lut_s%d" % (idx + 1), MAX_LUT_SPEED)
+        self.emc_fan.lut_enabled = current_mode
+
+
+class EMC2101_LUT(EMC2101):  # pylint: disable=too-many-instance-attributes
+    """Driver for the EMC2101 Fan Controller.
+    :param ~busio.I2C i2c_bus: The I2C bus the EMC is connected to.
+    """
+
+    _fan_pwm_clock_select = RWBit(_FAN_CONFIG, 3)
+    _fan_pwm_clock_override = RWBit(_FAN_CONFIG, 2)
+    _pwm_freq = RWBits(5, _PWM_FREQ, 0)
+    _pwm_freq_div = UnaryStruct(_PWM_DIV, "<B")
+
+    lut_temperature_hysteresis = UnaryStruct(_LUT_HYSTERESIS, "<B")
+    """The amount of hysteresis in Degrees celcius of hysteresis applied to temperature readings
+    used for the LUT. As the temperature drops, the controller will switch to a lower LUT entry when
+    the measured value is belowthe lower entry's threshold, minus the hysteresis value"""
+
+    def __init__(self, i2c_bus):
+        super().__init__(i2c_bus)
+
+        self.initialize()
+        self._lut = FanSpeedLUT(self)
+
+    def initialize(self):
+        """Reset the controller to an initial default configuration"""
+        self.lut_enabled = False
+        self._fan_pwm_clock_override = True
+        super().initialize()
+
+    def set_pwm_clock(self, use_preset=False, use_slow=False):
+        """
+             Select the PWM clock source, chosing between two preset clocks or by configuring the
+             clock using `pwm_frequency` and `pwm_frequency_divisor`.
+
+        :param bool use_preset:
+         True: Select between two preset clock sources
+         False: The PWM clock is set by `pwm_frequency` and `pwm_frequency_divisor`
+        :param bool use_slow:
+             True: Use the 1.4kHz clock
+             False: Use the 360kHz clock.
+        :type priority: integer or None
+        :return: None
+        :raises AttributeError: if use_preset is not a `bool`
+        :raises AttributeError: if use_slow is not a `bool`
+
+        """
+
+        if not isinstance(use_preset, bool):
+            raise AttributeError("use_preset must be given a bool")
+        if not isinstance(use_slow, bool):
+            raise AttributeError("use_slow_pwm must be given a bool")
+
+        self._fan_pwm_clock_override = not use_preset
+        self._fan_pwm_clock_select = use_slow
+
+    @property
+    def pwm_frequency(self):
+        """Selects the base clock frequency used for the fan PWM output"""
+        return self._pwm_freq
+
+    @pwm_frequency.setter
+    def pwm_frequency(self, value):
+        if value < 0 or value > 0x1F:
+            raise AttributeError("pwm_frequency must be from 0-31")
+        self._pwm_freq_div = value
+
+    @property
+    def pwm_frequency_divisor(self):
+        """The Divisor applied to the PWM frequency to set the final frequency"""
+        return self._pwm_freq_div
+
+    @pwm_frequency_divisor.setter
+    def pwm_frequency_divisor(self, divisor):
+        if divisor < 0 or divisor > 255:
+            raise AttributeError("pwm_frequency_divisor must be from 0-255")
+        self._pwm_freq_div = divisor
+
+    @property
+    def lut_enabled(self):
+        """Enable or disable the internal look up table used to map a given temperature
+        to a fan speed. When the LUT is disabled fan speed can be changed with `manual_fan_speed`"""
+        return not self._fan_lut_prog
+
+    @lut_enabled.setter
+    def lut_enabled(self, enable_lut):
+        self._fan_lut_prog = not enable_lut
+
+    @property
+    def lut(self):
+        """The dict-like representation of the LUT"""
+        return self._lut
diff --git a/examples/emc2101_lut_example.py b/examples/emc2101_lut_example.py
index a68f703..3322105 100644
--- a/examples/emc2101_lut_example.py
+++ b/examples/emc2101_lut_example.py
@@ -4,12 +4,12 @@
 import time
 import board
 import busio
-from adafruit_emc2101 import EMC2101
+from adafruit_emc2101.emc2101_lut import EMC2101_LUT
 
 i2c = busio.I2C(board.SCL, board.SDA)
 
 FAN_MAX_RPM = 1700
-emc = EMC2101(i2c)
+emc = EMC2101_LUT(i2c)
 emc.manual_fan_speed = 50
 time.sleep(1)
 emc.lut[27] = 25
diff --git a/examples/set_pwm_freq.py b/examples/set_pwm_freq.py
index faf8dc8..3dda875 100644
--- a/examples/set_pwm_freq.py
+++ b/examples/set_pwm_freq.py
@@ -4,11 +4,11 @@
 import time
 import board
 import busio
-from adafruit_emc2101 import EMC2101
+from adafruit_emc2101.emc2101_lut import EMC2101_LUT
 
 i2c = busio.I2C(board.SCL, board.SDA)
 
-emc = EMC2101(i2c)
+emc = EMC2101_LUT(i2c)
 emc.set_pwm_clock(use_preset=False)
 # Datasheet recommends using the maximum value of 31 (0x1F)
 # to provide the highest effective resolution

From 3e694b7371215f64357801cb6098191ca41a77b9 Mon Sep 17 00:00:00 2001
From: Ryan Pavlik <ryan.pavlik@gmail.com>
Date: Sun, 14 Mar 2021 13:04:44 -0500
Subject: [PATCH 03/12] Update docs

---
 docs/api.rst | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/docs/api.rst b/docs/api.rst
index daa9bd5..a798197 100644
--- a/docs/api.rst
+++ b/docs/api.rst
@@ -6,3 +6,7 @@
 
 .. automodule:: adafruit_emc2101
    :members:
+
+
+.. automodule:: adafruit_emc2101.emc2101_lut
+   :members:

From a8c1adaa9d28776a55aa1c4d0253f26eebb28268 Mon Sep 17 00:00:00 2001
From: Ryan Pavlik <ryan.pavlik@collabora.com>
Date: Tue, 16 Mar 2021 09:36:40 -0500
Subject: [PATCH 04/12] Slightly adjust examples

---
 examples/emc2101_lut_example.py | 4 ++--
 examples/set_pwm_freq.py        | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/examples/emc2101_lut_example.py b/examples/emc2101_lut_example.py
index 3322105..9c162e0 100644
--- a/examples/emc2101_lut_example.py
+++ b/examples/emc2101_lut_example.py
@@ -4,12 +4,12 @@
 import time
 import board
 import busio
-from adafruit_emc2101.emc2101_lut import EMC2101_LUT
+from adafruit_emc2101.emc2101_lut import EMC2101_LUT as EMC2101
 
 i2c = busio.I2C(board.SCL, board.SDA)
 
 FAN_MAX_RPM = 1700
-emc = EMC2101_LUT(i2c)
+emc = EMC2101(i2c)
 emc.manual_fan_speed = 50
 time.sleep(1)
 emc.lut[27] = 25
diff --git a/examples/set_pwm_freq.py b/examples/set_pwm_freq.py
index 3dda875..78df320 100644
--- a/examples/set_pwm_freq.py
+++ b/examples/set_pwm_freq.py
@@ -4,11 +4,11 @@
 import time
 import board
 import busio
-from adafruit_emc2101.emc2101_lut import EMC2101_LUT
+from adafruit_emc2101.emc2101_lut import EMC2101_LUT as EMC2101
 
 i2c = busio.I2C(board.SCL, board.SDA)
 
-emc = EMC2101_LUT(i2c)
+emc = EMC2101(i2c)
 emc.set_pwm_clock(use_preset=False)
 # Datasheet recommends using the maximum value of 31 (0x1F)
 # to provide the highest effective resolution

From 030db8d10d61b2722a4814ed6fb69877228e85cf Mon Sep 17 00:00:00 2001
From: Ryan Pavlik <ryan.pavlik@collabora.com>
Date: Tue, 16 Mar 2021 14:59:23 -0500
Subject: [PATCH 05/12] Simplify LUT using StructArray, and allow deleting
 entries by assigning None

---
 adafruit_emc2101/emc2101_lut.py | 51 ++++++++++++---------------------
 1 file changed, 19 insertions(+), 32 deletions(-)

diff --git a/adafruit_emc2101/emc2101_lut.py b/adafruit_emc2101/emc2101_lut.py
index 4a818d8..dba477a 100644
--- a/adafruit_emc2101/emc2101_lut.py
+++ b/adafruit_emc2101/emc2101_lut.py
@@ -8,7 +8,7 @@
 Brushless fan controller: extended functionality
 
 
-* Author(s): Bryan Siepert
+* Author(s): Bryan Siepert, Ryan Pavlik
 
 Implementation Notes
 --------------------
@@ -31,6 +31,7 @@
 """
 
 from micropython import const
+from adafruit_register.i2c_struct_array import StructArray
 from adafruit_register.i2c_struct import UnaryStruct
 from adafruit_register.i2c_bit import RWBit
 from adafruit_register.i2c_bits import RWBits
@@ -43,6 +44,7 @@
 _PWM_FREQ = const(0x4D)
 _PWM_DIV = const(0x4E)
 _LUT_HYSTERESIS = const(0x4F)
+_LUT_BASE = const(0x50)
 
 MAX_LUT_SPEED = 0x3F  # 6-bit value
 MAX_LUT_TEMP = 0x7F  # 7-bit
@@ -56,30 +58,8 @@ class FanSpeedLUT:
     """A class used to provide a dict-like interface to the EMC2101's Temperature to Fan speed
     Look Up Table"""
 
-    # seems like a pain but ¯\_(ツ)_/¯
-    _fan_lut_t1 = UnaryStruct(0x50, "<B")
-    _fan_lut_s1 = UnaryStruct(0x51, "<B")
-
-    _fan_lut_t2 = UnaryStruct(0x52, "<B")
-    _fan_lut_s2 = UnaryStruct(0x53, "<B")
-
-    _fan_lut_t3 = UnaryStruct(0x54, "<B")
-    _fan_lut_s3 = UnaryStruct(0x55, "<B")
-
-    _fan_lut_t4 = UnaryStruct(0x56, "<B")
-    _fan_lut_s4 = UnaryStruct(0x57, "<B")
-
-    _fan_lut_t5 = UnaryStruct(0x58, "<B")
-    _fan_lut_s5 = UnaryStruct(0x59, "<B")
-
-    _fan_lut_t6 = UnaryStruct(0x5A, "<B")
-    _fan_lut_s6 = UnaryStruct(0x5B, "<B")
-
-    _fan_lut_t7 = UnaryStruct(0x5C, "<B")
-    _fan_lut_s7 = UnaryStruct(0x5D, "<B")
-
-    _fan_lut_t8 = UnaryStruct(0x5E, "<B")
-    _fan_lut_s8 = UnaryStruct(0x5F, "<B")
+    # 8 (Temperature, Speed) pairs in increasing order
+    _fan_lut = StructArray(_LUT_BASE, "<B", 16)
 
     def __init__(self, fan_obj):
         self.emc_fan = fan_obj
@@ -96,9 +76,14 @@ def __getitem__(self, index):
     def __setitem__(self, index, value):
         if not isinstance(index, int):
             raise IndexError
-        if value > 100.0 or value < 0:
+        if value is None:
+            # Assign None to remove this entry
+            del self.lut_values[index]
+        elif value > 100.0 or value < 0:
+            # Range check
             raise AttributeError("LUT values must be a fan speed from 0-100%")
-        self.lut_values[index] = value
+        else:
+            self.lut_values[index] = value
         self._update_lut()
 
     def __repr__(self):
@@ -137,15 +122,17 @@ def _update_lut(self):
         # get and sort the new lut keys so that we can assign them in order
         for idx, current_temp in enumerate(sorted(self.lut_values.keys())):
             current_speed = _speed_to_lsb(self.lut_values[current_temp])
-            setattr(self, "_fan_lut_t%d" % (idx + 1), current_temp)
-            setattr(self, "_fan_lut_s%d" % (idx + 1), current_speed)
+            self._set_lut_entry(idx, current_temp, current_speed)
 
         # Set the remaining LUT entries to the default (Temp/Speed = max value)
-        for idx in range(8)[len(self.lut_values) :]:
-            setattr(self, "_fan_lut_t%d" % (idx + 1), MAX_LUT_TEMP)
-            setattr(self, "_fan_lut_s%d" % (idx + 1), MAX_LUT_SPEED)
+        for idx in range(len(self.lut_values), 8):
+            self._set_lut_entry(idx, MAX_LUT_TEMP, MAX_LUT_SPEED)
         self.emc_fan.lut_enabled = current_mode
 
+    def _set_lut_entry(self, idx, temp, speed):
+        self._fan_lut[idx * 2] = bytearray((temp,))
+        self._fan_lut[idx * 2 + 1] = bytearray((speed,))
+
 
 class EMC2101_LUT(EMC2101):  # pylint: disable=too-many-instance-attributes
     """Driver for the EMC2101 Fan Controller.

From cc0669cd82ff7577b453c1a41978ec94d4de288f Mon Sep 17 00:00:00 2001
From: Ryan Pavlik <ryan.pavlik@collabora.com>
Date: Tue, 16 Mar 2021 14:08:16 -0500
Subject: [PATCH 06/12] Minor performance tweak

---
 adafruit_emc2101/emc2101_lut.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/adafruit_emc2101/emc2101_lut.py b/adafruit_emc2101/emc2101_lut.py
index dba477a..96d4e36 100644
--- a/adafruit_emc2101/emc2101_lut.py
+++ b/adafruit_emc2101/emc2101_lut.py
@@ -93,7 +93,7 @@ def __repr__(self):
     def __str__(self):
         """return the official string representation of the LUT"""
         value_strs = []
-        lut_keys = list(sorted(self.lut_values.keys()))
+        lut_keys = tuple(sorted(self.lut_values.keys()))
         for temp in lut_keys:
             fan_drive = self.lut_values[temp]
             value_strs.append("%d deg C => %.1f%% duty cycle" % (temp, fan_drive))

From b75099fcc12f6828061bbfac3b0769d0a1e24e13 Mon Sep 17 00:00:00 2001
From: Ryan Pavlik <ryan.pavlik@collabora.com>
Date: Tue, 16 Mar 2021 14:59:33 -0500
Subject: [PATCH 07/12] Docs improvements

---
 adafruit_emc2101/__init__.py    | 19 ++++++++++++++-----
 adafruit_emc2101/emc2101_lut.py | 21 +++++++++++++++------
 docs/examples.rst               |  4 ++++
 3 files changed, 33 insertions(+), 11 deletions(-)

diff --git a/adafruit_emc2101/__init__.py b/adafruit_emc2101/__init__.py
index 24df5ec..bd93543 100644
--- a/adafruit_emc2101/__init__.py
+++ b/adafruit_emc2101/__init__.py
@@ -21,9 +21,8 @@
 
 * Adafruit CircuitPython firmware for the supported boards:
   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
+* Adafruit's Bus Device library: https://github.com/adafruit/Adafruit_CircuitPython_BusDevice
+* Adafruit's Register library: https://github.com/adafruit/Adafruit_CircuitPython_Register
 """
 
 from micropython import const
@@ -133,8 +132,13 @@ class SpinupTime(CV):
 
 
 class EMC2101:  # pylint: disable=too-many-instance-attributes
-    """Driver for the EMC2101 Fan Controller.
+    """Basic driver for the EMC2101 Fan Controller.
+
     :param ~busio.I2C i2c_bus: The I2C bus the EMC is connected to.
+
+    If you need control over PWM frequency and the controller's built in temperature/speed
+    look-up table (LUT), you will need :class:`emc2101_lut.EMC2101_LUT` which extends this
+    class to add those features, at the cost of increased memory usage.
     """
 
     _part_id = ROUnaryStruct(_REG_PARTID, "<B")
@@ -238,7 +242,12 @@ def manual_fan_speed(self, fan_speed):
     @property
     def lut_enabled(self):
         """Enable or disable the internal look up table used to map a given temperature
-        to a fan speed. When the LUT is disabled fan speed can be changed with `manual_fan_speed`"""
+        to a fan speed.
+
+        When the LUT is disabled (the default), fan speed can be changed with `manual_fan_speed`.
+        To actually set this to True and modify the LUT, you need to use the extended version of
+        this driver, :class:`emc2101_lut.EMC2101_LUT`
+        """
         return not self._fan_lut_prog
 
     @property
diff --git a/adafruit_emc2101/emc2101_lut.py b/adafruit_emc2101/emc2101_lut.py
index 96d4e36..3679215 100644
--- a/adafruit_emc2101/emc2101_lut.py
+++ b/adafruit_emc2101/emc2101_lut.py
@@ -22,10 +22,10 @@
 * Adafruit CircuitPython firmware for the supported boards:
   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
+* Adafruit's Bus Device library: https://github.com/adafruit/Adafruit_CircuitPython_BusDevice
+* Adafruit's Register library: https://github.com/adafruit/Adafruit_CircuitPython_Register
 
-The class defined here may be used instead of adafruit_emc2101.EMC2101,
+The class defined here may be used instead of :class:`adafruit_emc2101.EMC2101`,
 if your device has enough RAM to support it. This class adds LUT control
 and PWM frequency control to the base feature set.
 """
@@ -56,7 +56,13 @@ def _speed_to_lsb(percentage):
 
 class FanSpeedLUT:
     """A class used to provide a dict-like interface to the EMC2101's Temperature to Fan speed
-    Look Up Table"""
+    Look Up Table.
+
+    Keys are integer temperatures, values are fan duty cycles between 0 and 100.
+    A max of 8 values may be stored.
+
+    To remove a single stored point in the LUT, assign it as `None`.
+    """
 
     # 8 (Temperature, Speed) pairs in increasing order
     _fan_lut = StructArray(_LUT_BASE, "<B", 16)
@@ -135,7 +141,10 @@ def _set_lut_entry(self, idx, temp, speed):
 
 
 class EMC2101_LUT(EMC2101):  # pylint: disable=too-many-instance-attributes
-    """Driver for the EMC2101 Fan Controller.
+    """Driver for the EMC2101 Fan Controller, with PWM frequency and LUT control.
+
+    See :class:`adafruit_emc2101.EMC2101` for the base/common functionality.
+
     :param ~busio.I2C i2c_bus: The I2C bus the EMC is connected to.
     """
 
@@ -221,5 +230,5 @@ def lut_enabled(self, enable_lut):
 
     @property
     def lut(self):
-        """The dict-like representation of the LUT"""
+        """The dict-like representation of the LUT, actually of type :class:`FanSpeedLUT`"""
         return self._lut
diff --git a/docs/examples.rst b/docs/examples.rst
index 89b6025..5adfe22 100644
--- a/docs/examples.rst
+++ b/docs/examples.rst
@@ -11,6 +11,8 @@ LUT Usage Example
 -----------------
 
 Use the temperature to fan speed Look Up Table to automatically control the fan speed.
+This example requires more memory than the first one because it needs to use the extended
+:class:`adafruit_emc2101.emc2101_lut.EMC2101_LUT` driver to access LUT functionality.
 
 .. literalinclude:: ../examples/emc2101_lut_example.py
     :caption: examples/emc2101_lut_example.py
@@ -21,6 +23,8 @@ PWM Tuning
 -----------------
 
 Adjust the EMC2101s PWM settings to fit your application.
+This example requires more memory than the first one because it needs to use the extended
+:class:`adafruit_emc2101.emc2101_lut.EMC2101_LUT` driver to access LUT functionality.
 
 .. literalinclude:: ../examples/set_pwm_freq.py
     :caption: examples/set_pwm_freq.py

From 896cd98418f34b0a7b61baa611e65d3f1c2c9604 Mon Sep 17 00:00:00 2001
From: Ryan Pavlik <ryan.pavlik@collabora.com>
Date: Tue, 16 Mar 2021 14:30:39 -0500
Subject: [PATCH 08/12] Fix typo in example

---
 examples/emc2101_lut_example.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/emc2101_lut_example.py b/examples/emc2101_lut_example.py
index 9c162e0..2e4ce04 100644
--- a/examples/emc2101_lut_example.py
+++ b/examples/emc2101_lut_example.py
@@ -27,6 +27,6 @@
 time.sleep(3)
 print("50%% duty cycle is %f RPM:" % emc.fan_speed)
 
-emc.forced_ext_temp = 43  # over 30, should be 50%
+emc.forced_ext_temp = 43  # over 42, should be 75%
 time.sleep(3)
 print("75%% duty cycle is %f RPM:" % emc.fan_speed)

From ce7d6ca3819949d47d79ccb4959d7f19c36c3681 Mon Sep 17 00:00:00 2001
From: Ryan Pavlik <ryan.pavlik@collabora.com>
Date: Tue, 16 Mar 2021 14:38:46 -0500
Subject: [PATCH 09/12] Improve comments

---
 adafruit_emc2101/__init__.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/adafruit_emc2101/__init__.py b/adafruit_emc2101/__init__.py
index bd93543..01fed23 100644
--- a/adafruit_emc2101/__init__.py
+++ b/adafruit_emc2101/__init__.py
@@ -145,12 +145,15 @@ class to add those features, at the cost of increased memory usage.
     _mfg_id = ROUnaryStruct(_REG_MFGID, "<B")
     _int_temp = ROUnaryStruct(_INTERNAL_TEMP, "<b")
 
+    # Some of these registers are defined as two halves because
+    # the chip does not support multi-byte reads or writes, and there
+    # is currently no way to tell Struct to do a transaction for each byte.
+
     # IMPORTANT! the sign bit for the external temp is in the msbyte so mark it as signed
     # and lsb as unsigned
     _ext_temp_msb = ROUnaryStruct(_EXTERNAL_TEMP_MSB, "<b")
     _ext_temp_lsb = ROUnaryStruct(_EXTERNAL_TEMP_LSB, "<B")
 
-    # _tach_read = ROUnaryStruct(_TACH_LSB, "<H")
     _tach_read_lsb = ROUnaryStruct(_TACH_LSB, "<B")
     _tach_read_msb = ROUnaryStruct(_TACH_MSB, "<B")
     _tach_mode_enable = RWBit(_REG_CONFIG, 2)

From 429fc20b2cf09f521f513ed7514588dea8be718c Mon Sep 17 00:00:00 2001
From: Ryan Pavlik <ryan.pavlik@collabora.com>
Date: Tue, 16 Mar 2021 14:39:01 -0500
Subject: [PATCH 10/12] remove extra space

---
 adafruit_emc2101/__init__.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/adafruit_emc2101/__init__.py b/adafruit_emc2101/__init__.py
index 01fed23..4d0602d 100644
--- a/adafruit_emc2101/__init__.py
+++ b/adafruit_emc2101/__init__.py
@@ -232,7 +232,7 @@ def manual_fan_speed(self):
     @manual_fan_speed.setter
     def manual_fan_speed(self, fan_speed):
         if fan_speed not in range(0, 101):
-            raise AttributeError("manual_fan_speed must be from 0-100 ")
+            raise AttributeError("manual_fan_speed must be from 0-100")
 
         # convert from a percentage to an lsb value
         percentage = fan_speed / 100.0

From 7b27d9a58345b7e80cc35156819c06b0c7ebb84f Mon Sep 17 00:00:00 2001
From: Ryan Pavlik <ryan.pavlik@collabora.com>
Date: Tue, 16 Mar 2021 14:39:29 -0500
Subject: [PATCH 11/12] Fix typo

---
 adafruit_emc2101/__init__.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/adafruit_emc2101/__init__.py b/adafruit_emc2101/__init__.py
index 4d0602d..0ccec77 100644
--- a/adafruit_emc2101/__init__.py
+++ b/adafruit_emc2101/__init__.py
@@ -63,7 +63,7 @@ class CV:
 
     @classmethod
     def add_values(cls, value_tuples):
-        "creates CV entires"
+        "creates CV entries"
         cls.string = {}
         cls.lsb = {}
 

From 97ecd43415843e24520294a5ea3138922bd05a20 Mon Sep 17 00:00:00 2001
From: Ryan Pavlik <ryan.pavlik@collabora.com>
Date: Tue, 16 Mar 2021 14:29:13 -0500
Subject: [PATCH 12/12] Add ability to clear LUT

---
 adafruit_emc2101/emc2101_lut.py | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/adafruit_emc2101/emc2101_lut.py b/adafruit_emc2101/emc2101_lut.py
index 3679215..be770ca 100644
--- a/adafruit_emc2101/emc2101_lut.py
+++ b/adafruit_emc2101/emc2101_lut.py
@@ -62,6 +62,7 @@ class FanSpeedLUT:
     A max of 8 values may be stored.
 
     To remove a single stored point in the LUT, assign it as `None`.
+    To clear all entries, use :meth:`FanSpeedLUT.clear`
     """
 
     # 8 (Temperature, Speed) pairs in increasing order
@@ -139,6 +140,11 @@ def _set_lut_entry(self, idx, temp, speed):
         self._fan_lut[idx * 2] = bytearray((temp,))
         self._fan_lut[idx * 2 + 1] = bytearray((speed,))
 
+    def clear(self):
+        """Clear all LUT entries."""
+        self.lut_values = {}
+        self._update_lut()
+
 
 class EMC2101_LUT(EMC2101):  # pylint: disable=too-many-instance-attributes
     """Driver for the EMC2101 Fan Controller, with PWM frequency and LUT control.
@@ -232,3 +238,7 @@ def lut_enabled(self, enable_lut):
     def lut(self):
         """The dict-like representation of the LUT, actually of type :class:`FanSpeedLUT`"""
         return self._lut
+
+    def clear_lut(self):
+        """Clear all LUT entries."""
+        self._lut.clear()