initial commit

button.cpp

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+/*----------------------------------------------------------------------*
+ * button.cpp -- Library for reading momentary contact switches like	*
+ * tactile button switches.	Intended for use in state machine 			*
+ * constructs.  Use the read() function to read all buttons in the 		*
+ * main loop, which should execute as fast as possible, or at least		*
+ * very frequently.														*
+ *																		*
+ * Jack Christensen 11May2011											*
+ *                                                                      *
+ * This work is licensed under the Creative Commons Attribution-        *
+ * ShareAlike 3.0 Unported License. To view a copy of this license,     *
+ * visit http://creativecommons.org/licenses/by-sa/3.0/ or send a       *
+ * letter to Creative Commons, 171 Second Street, Suite 300,            *
+ * San Francisco, California, 94105, USA.                               *
+ *----------------------------------------------------------------------*/
+#include "WProgram.h"
+#include "button.h"
+
+//the constructor button(pin, puEnabled, invert, dbTime) instantiates a button object.
+//pin is the Arduino pin the button is connected to.
+//puEnabled enables the AVR internal pullup resistor if != 0 (can use true or false).
+//invert = 0 interprets a high state as pressed, low as released.
+//invert != 0 interprets a high state as released, low as pressed  (can use true or false).
+//dbTime is the debounce time in milliseconds.
+//note that invert cannot be implied from puEnabled since an external pullup could be used.
+button::button(uint8_t pin, uint8_t puEnabled, uint8_t invert, uint32_t dbTime)
+{
+	_pin = pin;
+	_puEnabled = puEnabled;
+	_invert = invert;
+	_dbTime = dbTime;
+	pinMode(_pin, INPUT);
+    if (_puEnabled != 0)
+    	digitalWrite(_pin, HIGH);		//enable pullup resistor
+	_state = digitalRead(_pin);
+	if (_invert != 0) _state = !_state;
+	_time = millis();
+	_lastState = _state;
+	_changed = 0;
+	_lastTime = _time;
+	_lastChange = _time;
+}
+
+//read() returns the state of the button 1 (pressed), or 0 (released),
+//does debouncing, and also captures and maintains times, previous states, etc.
+uint8_t button::read(void)
+{
+	static uint32_t ms;
+	static uint8_t pinVal;
+
+	ms = millis();
+	pinVal = digitalRead(_pin);
+	if (_invert != 0) pinVal = !pinVal;
+	if (ms < _lastChange + _dbTime) {
+		_lastTime = _time;
+		_time = ms;
+		_changed = 0;
+		return _state;
+	}
+	else {
+		_lastTime = _time;
+		_lastState = _state;
+		_state = pinVal;
+		_time = ms;
+		if (_state != _lastState)	{
+			_lastChange = ms;
+			_changed = 1;
+		}
+		else {
+			_changed = 0;
+		}
+		return _state;
+	}
+}
+
+//isPressed() and isReleased() check the button state when it was last read,
+//and return false (0) or true (!=0) accordingly.
+//These functions do not cause the button to be read.
+uint8_t button::isPressed(void)
+{
+	return _state == 0 ? 0 : 1;
+}
+
+uint8_t button::isReleased(void)
+{
+	return _state == 0 ? 1 : 0;
+}
+
+//wasPressed() and wasReleased() check the button state to see if it changed
+//between the last two reads and return false (0) or true (!=0) accordingly.
+//These functions do not cause the button to be read.
+uint8_t button::wasPressed(void)
+{
+	return _state && _changed;
+}
+
+uint8_t button::wasReleased(void)
+{
+	return !_state && _changed;
+}
+
+//pressedFor(ms) and releasedFor(ms) check to see if the button is pressed (or released),
+//and has been in that state for the specified time. Returns false (0) or true (1) accordingly.
+//These functions do not cause the button to be read.
+uint8_t button::pressedFor(uint32_t ms)
+{
+	return (_state == 1 && _time - _lastChange >= ms) ? 1 : 0;
+}
+
+uint8_t button::releasedFor(uint32_t ms)
+{
+	return (_state == 0 && _time - _lastChange >= ms) ? 1 : 0;
+}
+
+//lastChange() returns the time of the last state change in milliseconds.
+uint32_t button::lastChange(void)
+{
+	return _lastChange;
+}

button.h

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+/*----------------------------------------------------------------------*
+ * button.h -- Library for reading momentary contact switches like		*
+ * tactile button switches.												*
+ *																		*
+ * Jack Christensen 11 May 2011											*
+ *                                                                      *
+ * This work is licensed under the Creative Commons Attribution-        *
+ * ShareAlike 3.0 Unported License. To view a copy of this license,     *
+ * visit http://creativecommons.org/licenses/by-sa/3.0/ or send a       *
+ * letter to Creative Commons, 171 Second Street, Suite 300,            *
+ * San Francisco, California, 94105, USA.                               *
+ *----------------------------------------------------------------------*/
+#ifndef button_h
+#define button_h
+#include "WProgram.h"
+class button
+{
+	public:
+		button(uint8_t pin, uint8_t puEnabled, uint8_t invert, uint32_t dbTime);
+		uint8_t read();
+		uint8_t isPressed();
+		uint8_t isReleased();
+		uint8_t wasPressed();
+		uint8_t wasReleased();
+		uint8_t pressedFor(uint32_t ms);
+		uint8_t releasedFor(uint32_t ms);
+		uint32_t lastChange();
+	private:
+		uint8_t _pin;			//arduino pin number
+		uint8_t _puEnabled;		//internal pullup resistor enabled
+		uint8_t _invert;		//if 0, interpret high state as pressed, else interpret low state as pressed
+		uint8_t _state;			//current button state
+		uint8_t _lastState;		//previous button state
+		uint8_t _changed;		//state changed since last read
+		uint32_t _time;			//time of current state (all times are in ms)
+		uint32_t _lastTime;		//time of previous state
+		uint32_t _lastChange;	//time of last state change
+		uint32_t _dbTime;		//debounce time
+};
+#endif

keywords.txt

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+button	KEYWORD1
+read	KEYWORD2
+isPressed	KEYWORD2
+isReleased	KEYWORD2
+wasPressed	KEYWORD2
+wasReleased	KEYWORD2
+pressedFor	KEYWORD2
+releasedFor	KEYWORD2
+lastChange	KEYWORD2