Merge pull request #52 from brentru/add-pwmout-implementation

PWMOut class for ESP32SPI

Author: brentru

adafruit_esp32spi/PWMOut.py

@@ -0,0 +1,108 @@
+# The MIT License (MIT)
+#
+# Copyright (c) 2019 Brent Rubell for Adafruit Industries
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+"""
+`PWMOut`
+==============================
+PWMOut CircuitPython API for ESP32SPI.
+
+* Author(s): Brent Rubell
+"""
+
+class PWMOut():
+    """
+    Implementation of CircuitPython PWMOut for ESP32SPI.
+
+    :param int esp_pin: Valid ESP32 GPIO Pin, predefined in ESP32_GPIO_PINS.
+    :param ESP_SPIcontrol esp: The ESP object we are using.
+    :param int duty_cycle: The fraction of each pulse which is high, 16-bit.
+    :param int frequency: The target frequency in Hertz (32-bit).
+    :param bool variable_frequency: True if the frequency will change over time.
+    """
+    ESP32_PWM_PINS = set([0, 1, 2, 4, 5,
+                          12, 13, 14, 15,
+                          16, 17, 18, 19,
+                          21, 22, 23, 25,
+                          26, 27, 32, 33])
+    def __init__(self, esp, pwm_pin, *, frequency=500, duty_cycle=0, variable_frequency=False):
+        if pwm_pin in self.ESP32_PWM_PINS:
+            self._pwm_pin = pwm_pin
+        else:
+            raise AttributeError("Pin %d is not a valid ESP32 GPIO Pin."%pwm_pin)
+        self._esp = esp
+        self._duty_cycle = duty_cycle
+        self._freq = frequency
+        self._var_freq = variable_frequency
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_value, exc_traceback):
+        self.deinit()
+
+    def deinit(self):
+        """De-initalize the PWMOut object."""
+        self._duty_cycle = 0
+        self._freq = 0
+        self._pwm_pin = None
+
+    def _is_deinited(self):
+        """Checks if PWMOut object has been previously de-initalized"""
+        if self._pwm_pin is None:
+            raise ValueError("PWMOut Object has been deinitialized and can no longer "
+                             "be used. Create a new PWMOut object.")
+
+    @property
+    def duty_cycle(self):
+        """Returns the PWMOut object's duty cycle as a
+        ratio from 0.0 to 1.0."""
+        self._is_deinited()
+        return self._duty_cycle
+
+    @duty_cycle.setter
+    def duty_cycle(self, duty_cycle):
+        """Sets the PWMOut duty cycle.
+        :param float duty_cycle: Between 0.0 (low) and 1.0 (high).
+        :param int duty_cycle: Between 0 (low) and 1 (high).
+        """
+        self._is_deinited()
+        if not isinstance(duty_cycle, (int, float)):
+            raise TypeError("Invalid duty_cycle, should be int or float.")
+        duty_cycle /= 65535.0
+        if not 0.0 <= duty_cycle <= 1.0:
+            raise ValueError("Invalid duty_cycle, should be between 0.0 and 1.0")
+        self._esp.set_analog_write(self._pwm_pin, duty_cycle)
+
+    @property
+    def frequency(self):
+        """Returns the PWMOut object's frequency value."""
+        self._is_deinited()
+        return self._freq
+
+    @frequency.setter
+    def frequency(self, freq):
+        """Sets the PWMOut object's frequency value.
+        :param int freq: 32-bit value that dictates the PWM frequency in Hertz.
+        NOTE: Only writeable when constructed with variable_Frequency=True.
+        """
+        self._is_deinited()
+        self._freq = freq
+        raise NotImplementedError("PWMOut Frequency not implemented in ESP32SPI")