diff options
Diffstat (limited to 'libraries/Servo/Servo.h')
| -rw-r--r-- | libraries/Servo/Servo.h | 213 |
1 files changed, 149 insertions, 64 deletions
diff --git a/libraries/Servo/Servo.h b/libraries/Servo/Servo.h index 583312e..f80339e 100644 --- a/libraries/Servo/Servo.h +++ b/libraries/Servo/Servo.h @@ -25,93 +25,178 @@ #ifndef _SERVO_H_ #define _SERVO_H_ -#include <stdint.h> +#include "libmaple_types.h" +#include "timer.h" -#include "wirish.h" /* hack for IDE compile */ -#include "HardwareTimer.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(). +#include "wirish_types.h" - 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 Servo::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. +#ifdef MAPLE_IDE +#include "wirish.h" /* hack for IDE compile */ +#endif - 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, the pin mapping mega table is your friend. +/* + * 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) +#define NOT_ATTACHED (-1) // Maximum angle in degrees you can write(), exclusive. Value chosen -// for Arduino compatibility. -#define SERVO_MAX_WRITE_ANGLE (200) - -// Default min (0 deg)/max(180 deg) pulse widths, in microseconds. -// Value chosen for Arduino compatibility. -#define SERVO_DEFAULT_MIN_PW (544) -#define SERVO_DEFAULT_MAX_PW (2400) +// for Arduino compatibility. This value is part of the public API; +// DO NOT CHANGE IT. +#define SERVO_MAX_WRITE_ANGLE 200 + +// 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 Servo { public: + /** + * @brief Construct a new Servo instance. + * + * The new instance will not be attached to any pin. + */ Servo(); - /* Pin has to have a timer channel associated with it already; - * sets pinMode to PWM and returns true iff successful (failure - * when pin doesn't support PWM). doesn't detach any ISRs - * associated with timer channel. */ - bool attach(uint8_t pin); - - /* Like attach(int), but with (inclusive) min (0 degree) and max - * (180 degree) pulse widths, in microseconds. + /** + * @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_t pin, uint16_t min, uint16_t max); - - /* Return pin number if currently attach()ed to a pin, - NOT_ATTACHED otherwise. */ - int attached() const { return pin; } + 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; } - /* Stop driving the wave by disabling the output compare - interrupt. Returns true if this call did anything. */ + /** + * @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(); - /* If value < MAX_WRITE_ANGLE, treated as an angle in degrees. - Otherwise, it's treated as a pulse width. */ - void write(unsigned int value); + /** + * @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); - /* If outside of [min, max] determined by attach(), it is clamped - to lie in that range. */ - void writeMicroseconds(uint16_t pulseWidth); - /* Return servo target angle, in degrees. This will lie between 0 - and 180. */ + /** + * Get the servomotor's target angle, in degrees. This will + * lie inside the range specified at attach() time. + * + * @see Servo::attach() + */ int read() const; - /* Returns the current pulse width, in microseconds. This will - lie within the [min, max] range. */ - uint16_t readMicroseconds() 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: - int8_t pin; - HardwareTimer *timer; - int channel; - uint16_t min; - uint16_t max; + int16 pin; + uint16 minPW; + uint16 maxPW; + int16 minAngle; + int16 maxAngle; + + void resetFields(void); }; #endif /* _SERVO_H_ */ |