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Diffstat (limited to 'libraries/Servo/Servo.h')
| -rw-r--r-- | libraries/Servo/Servo.h | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/libraries/Servo/Servo.h b/libraries/Servo/Servo.h new file mode 100644 index 0000000..94e1e00 --- /dev/null +++ b/libraries/Servo/Servo.h @@ -0,0 +1,196 @@ +/****************************************************************************** + * The MIT License + * + * Copyright (c) 2010, LeafLabs, LLC. + * + * 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. + *****************************************************************************/ + +#ifndef _SERVO_H_ +#define _SERVO_H_ + +#include <libmaple/libmaple_types.h> +#include <libmaple/timer.h> + +#include <wirish/wirish_types.h> + +/* + * Note on Arduino compatibility: + * + * In the Arduino implementation, PWM is done "by hand" in the sense + * that timer channels are hijacked in groups and an ISR is set which + * toggles Servo::attach()ed pins using digitalWrite(). + * + * While this scheme allows any pin to drive a servo, it chews up + * cycles and complicates the programmer's notion of when a particular + * timer channel will be in use. + * + * This implementation only allows Servo instances to attach() to pins + * that already have a timer channel associated with them, and just + * uses pwmWrite() to drive the wave. + * + * This introduces an incompatibility: while the Arduino + * implementation of attach() returns the affected channel on success + * and 0 on failure, this one returns true on success and false on + * failure. + * + * RC Servos expect a pulse every 20ms. Since periods are set for + * entire timers, rather than individual channels, attach()ing a Servo + * to a pin can interfere with other pins associated with the same + * timer. As always, your board's pin map is your friend. + */ + +// Pin number of unattached pins +#define NOT_ATTACHED (-1) + +// Default min/max pulse widths (in microseconds) and angles (in +// degrees). Values chosen for Arduino compatibility. These values +// are part of the public API; DO NOT CHANGE THEM. +#define SERVO_DEFAULT_MIN_PW 544 +#define SERVO_DEFAULT_MAX_PW 2400 +#define SERVO_DEFAULT_MIN_ANGLE 0 +#define SERVO_DEFAULT_MAX_ANGLE 180 + +/** Class for interfacing with RC servomotors. */ +class Servo { +public: + /** + * @brief Construct a new Servo instance. + * + * The new instance will not be attached to any pin. + */ + Servo(); + + /** + * @brief Associate this instance with a servomotor whose input is + * connected to pin. + * + * If this instance is already attached to a pin, it will be + * detached before being attached to the new pin. This function + * doesn't detach any interrupt attached with the pin's timer + * channel. + * + * @param pin Pin connected to the servo pulse wave input. This + * pin must be capable of PWM output. + * + * @param minPulseWidth Minimum pulse width to write to pin, in + * microseconds. This will be associated + * with a minAngle degree angle. Defaults to + * SERVO_DEFAULT_MIN_PW = 544. + * + * @param maxPulseWidth Maximum pulse width to write to pin, in + * microseconds. This will be associated + * with a maxAngle degree angle. Defaults to + * SERVO_DEFAULT_MAX_PW = 2400. + * + * @param minAngle Target angle (in degrees) associated with + * minPulseWidth. Defaults to + * SERVO_DEFAULT_MIN_ANGLE = 0. + * + * @param maxAngle Target angle (in degrees) associated with + * maxPulseWidth. Defaults to + * SERVO_DEFAULT_MAX_ANGLE = 180. + * + * @sideeffect May set pinMode(pin, PWM). + * + * @return true if successful, false when pin doesn't support PWM. + */ + bool attach(uint8 pin, + uint16 minPulseWidth=SERVO_DEFAULT_MIN_PW, + uint16 maxPulseWidth=SERVO_DEFAULT_MAX_PW, + int16 minAngle=SERVO_DEFAULT_MIN_ANGLE, + int16 maxAngle=SERVO_DEFAULT_MAX_ANGLE); + + /** + * @brief Check if this instance is attached to a servo. + * @return true if this instance is attached to a servo, false otherwise. + * @see Servo::attachedPin() + */ + bool attached() const { return this->pin != NOT_ATTACHED; } + + /** + * @brief Get the pin this instance is attached to. + * @return Pin number if currently attached to a pin, NOT_ATTACHED + * otherwise. + * @see Servo::attach() + */ + int attachedPin() const { return this->pin; } + + /** + * @brief Stop driving the servo pulse train. + * + * If not currently attached to a motor, this function has no effect. + * + * @return true if this call did anything, false otherwise. + */ + bool detach(); + + /** + * @brief Set the servomotor target angle. + * + * @param angle Target angle, in degrees. If the target angle is + * outside the range specified at attach() time, it + * will be clamped to lie in that range. + * + * @see Servo::attach() + */ + void write(int angle); + + + /** + * Get the servomotor's target angle, in degrees. This will + * lie inside the range specified at attach() time. + * + * @see Servo::attach() + */ + int read() const; + + /** + * @brief Set the pulse width, in microseconds. + * + * @param pulseWidth Pulse width to send to the servomotor, in + * microseconds. If outside of the range + * specified at attach() time, it is clamped to + * lie in that range. + * + * @see Servo::attach() + */ + void writeMicroseconds(uint16 pulseWidth); + + /** + * Get the current pulse width, in microseconds. This will + * lie within the range specified at attach() time. + * + * @see Servo::attach() + */ + uint16 readMicroseconds() const; + +private: + int16 pin; + uint16 minPW; + uint16 maxPW; + int16 minAngle; + int16 maxAngle; + + void resetFields(void); +}; + +#endif /* _SERVO_H_ */ |