Source code for adafruit_motor.motor

# SPDX-FileCopyrightText: 2021 Scott Shawcroft for Adafruit Industries
# SPDX-License-Identifier: MIT


Simple control of a DC motor. DC motors have two wires and should not be connected directly to
the PWM connections. Instead use intermediate circuitry to control a much stronger power source with
the PWM. The `Adafruit Stepper + DC Motor FeatherWing <>`_,
`Adafruit TB6612 1.2A DC/Stepper Motor Driver Breakout Board
<>`_ and `Adafruit Motor/Stepper/Servo Shield for Arduino v2
Kit - v2.3 <>`_ do this for popular form
factors already.

.. note:: The TB6612 boards feature three inputs XIN1, XIN2 and PWMX. Since we PWM the INs directly
  its expected that the PWM pin is consistently high.

* Author(s): Scott Shawcroft

    from typing import Optional, Type
    from types import TracebackType

        from pwmio import PWMOut
    except NotImplementedError:
        from circuitpython_typing.pwmio import PWMOut

except ImportError:

__version__ = "0.0.0-auto.0"
__repo__ = ""

"""Recirculation current fast decay mode (coasting)"""

"""Recirculation current slow decay mode (braking)"""

[docs]class DCMotor: """DC motor driver. ``positive_pwm`` and ``negative_pwm`` can be swapped if the motor runs in the opposite direction from what was expected for "forwards". Motor controller recirculation current decay mode is selectable and defaults to ``motor.FAST_DECAY`` (coasting). ``motor.SLOW_DECAY`` is recommended to improve spin threshold, speed-to-throttle linearity, and PWM frequency sensitivity. Decay mode settings only effect the operational performance of controller chips such as the DRV8833, DRV8871, and TB6612. Either decay mode setting is compatible with discrete h-bridge controller circuitry such as the L9110H and L293D; operational performance is not altered. :param ~pwmio.PWMOut positive_pwm: The motor input that causes the motor to spin forwards when high and the other is low. :param ~pwmio.PWMOut negative_pwm: The motor input that causes the motor to spin backwards when high and the other is low.""" def __init__(self, positive_pwm: PWMOut, negative_pwm: PWMOut) -> None: self._positive = positive_pwm self._negative = negative_pwm self._throttle = None self._decay_mode = FAST_DECAY @property def throttle(self) -> Optional[float]: """Motor speed, ranging from -1.0 (full speed reverse) to 1.0 (full speed forward), or ``None`` (controller off). If ``None``, both PWMs are turned full off. If ``0.0``, both PWMs are turned full on. """ return self._throttle @throttle.setter def throttle(self, value: Optional[float]) -> None: if value is not None and (value > 1.0 or value < -1.0): raise ValueError("Throttle must be None or between -1.0 and +1.0") self._throttle = value if value is None: # Turn off motor controller (high-Z) self._positive.duty_cycle = 0 self._negative.duty_cycle = 0 elif value == 0: # Brake motor (low-Z) self._positive.duty_cycle = 0xFFFF self._negative.duty_cycle = 0xFFFF else: duty_cycle = int(0xFFFF * abs(value)) if self._decay_mode == SLOW_DECAY: # Slow Decay (Braking) Mode if value < 0: self._positive.duty_cycle = 0xFFFF - duty_cycle self._negative.duty_cycle = 0xFFFF else: self._positive.duty_cycle = 0xFFFF self._negative.duty_cycle = 0xFFFF - duty_cycle else: # Default Fast Decay (Coasting) Mode if value < 0: self._positive.duty_cycle = 0 self._negative.duty_cycle = duty_cycle else: self._positive.duty_cycle = duty_cycle self._negative.duty_cycle = 0 @property def decay_mode(self) -> int: """Motor controller recirculation current decay mode. A value of ``motor.FAST_DECAY`` sets the motor controller to the default fast recirculation current decay mode (coasting); ``motor.SLOW_DECAY`` sets slow decay (braking) mode.""" return self._decay_mode @decay_mode.setter def decay_mode(self, mode: int = FAST_DECAY) -> None: if mode in (FAST_DECAY, SLOW_DECAY): self._decay_mode = mode else: raise ValueError( "Decay mode value must be either motor.FAST_DECAY or motor.SLOW_DECAY" ) def __enter__(self) -> "DCMotor": return self def __exit__( self, exception_type: Optional[Type[type]], exception_value: Optional[BaseException], traceback: Optional[TracebackType], ) -> None: self.throttle = None