Frank Lu
InterruptIn style DigitalIn debounced with callbacks for pin state change and pin state hold.
Diff: PinDetect.h
- Revision:
- 0:4f4ccb203a70
- Child:
- 1:611a8f5ac65c
diff -r 000000000000 -r 4f4ccb203a70 PinDetect.h
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/PinDetect.h Thu Jan 13 01:47:31 2011 +0000
@@ -0,0 +1,474 @@
+/*
+ Copyright (c) 2010 Andy Kirkham
+
+ 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 AJK_PIN_DETECT_H
+#define AJK_PIN_DETECT_H
+
+#ifndef MBED_H
+#include "mbed.h"
+#endif
+
+#ifndef PINDETECT_PIN_ASSTERED
+#define PINDETECT_PIN_ASSTERED 1
+#endif
+
+#define PINDETECT_PIN_DEASSTERED !PINDETECT_PIN_ASSTERED
+
+#ifndef PINDETECT_SAMPLE_PERIOD
+#define PINDETECT_SAMPLE_PERIOD 20000
+#endif
+
+#ifndef PINDETECT_ASSERT_COUNT
+#define PINDETECT_ASSERT_COUNT 1
+#endif
+
+#ifndef PINDETECT_HOLD_COUNT
+#define PINDETECT_HOLD_COUNT 50
+#endif
+
+namespace AjK {
+
+/** PinDetect adds mechanical switch debouncing to DigitialIn and interrupt callbacks.
+ *
+ * This is done by sampling the specified pin at regular intervals and detecting any
+ * change of state ( 0 -> 1 or 1 -> 0 ). When a state change is detected the attached
+ * callback handler is called. Additionally, if the pin stays in the same state after
+ * a state change for a defined period of time, an extra callback is made allowing a
+ * program to detect when a "key is pressed and held down" rather than a momentary
+ * key/switch press.
+ *
+ * All parameters are customisable which include:-
+ * <ul>
+ * <li> The sampling frequency. </li>
+ * <li> The number of continuous samples until a state change is detected. </li>
+ * <li> The number of continuous samples until a key is assumed held after a state change. </li>
+ * <li> The logic level which is assumed to be asserted (0volts or +volts). </li>
+ * </ul>
+ *
+ * Only callbacks that have been attached will be called by the library.
+ *
+ * Example:
+ * @code
+ * #include "mbed.h"
+ * #include "PinDetect.h"
+ *
+ * PinDetect pin( p30 );
+ * DigitialOut led1( LED1 );
+ * DigitialOut led2( LED2 );
+ * DigitialOut led3( LED3 );
+ * DigitialOut led4( LED4 );
+ *
+ * void keyPressed( void ) {
+ * led2 = 1;
+ * led3 = 0;
+ * led4 = 0;
+ * }
+ *
+ * void keyReleased( void ) {
+ * led2 = 0;
+ * led3 = 0;
+ * led4 = 0;
+ * }
+ *
+ * void keyPressedHeld( void ) {
+ * led3 = 1;
+ * }
+ *
+ * void keyReleasedHeld( void ) {
+ * led4 = 1;
+ * }
+ *
+ * int main() {
+ *
+ * pin.mode( PullDown );
+ * pin.attach_asserted( &keyPressed );
+ * pin.attach_deasserted( &keyReleased );
+ * pin.attach_asserted_held( &keyPressedHeld );
+ * pin.attach_deasserted_held( &keyReleasedHeld );
+ *
+ * // Sampling does not begin until you set a frequency.
+ * // The default is 20ms. If you want a different frequency
+ * // then pass the period in microseconds for example, for 10ms :-
+ * // pin.setSampleFrequency( 10000 );
+ * //
+ * pin.setSampleFrequency(); // Defaults to 20ms.
+ *
+ * while( 1 ) {
+ * led1 = !led1;
+ * wait( 0.2 );
+ * }
+ * }
+ * @endcode
+ *
+ * This example will flash led1 in a similar to a standard starting program.
+ *
+ * Applying a "1" (switch on) to pin 30 will switch on led2, removing the "1" to "0"
+ * (switch off) led2 goes out. Holding the "switch" at one for one second will switch
+ * on led3. An unasserted P30 (switched off) will, after one second illuminate led4
+ * when the deasserted calledback is called.
+ *
+ * The above is a very basic introduction. For more details:-
+ * @see example.h
+ */
+class PinDetect {
+public:
+
+ PinDetect() { error("You must supply a PinName"); }
+
+ /** PinDetect constructor
+ *
+ * @see http://mbed.org/handbook/DigitalIn
+ * @param p PinName is a valid pin that supports DigitalIn
+ */
+ PinDetect(PinName p) {
+ _sampleTime = PINDETECT_SAMPLE_PERIOD;
+ _samplesTillAssert = PINDETECT_ASSERT_COUNT;
+ _samplesTillHeld = 0;
+ _samplesTillAssertReload = PINDETECT_ASSERT_COUNT;
+ _samplesTillHeldReload = PINDETECT_HOLD_COUNT;
+ _assertValue = PINDETECT_PIN_ASSTERED;
+ _in = new DigitalIn(p);
+ _prevState = _in->read();
+ _ticker = new Ticker;
+ }
+
+ /** PinDetect destructor
+ */
+ ~PinDetect() {
+ if (_ticker) delete(_ticker);
+ if (_in) delete(_in);
+ }
+
+ /** Set the sampling time in microseconds.
+ *
+ * @param int The time between pin samples in microseconds.
+ */
+ void setSampleFrequency(int i = PINDETECT_SAMPLE_PERIOD) {
+ _sampleTime = i;
+ _ticker->attach_us(this, &PinDetect::isr, _sampleTime);
+ }
+
+ /** Set the value used as assert.
+ *
+ * Defaults to 1 (ie if pin == 1 then pin asserted).
+ *
+ * @param int New assert value (1 or 0)
+ */
+ void setAssertValue (int i = PINDETECT_PIN_ASSTERED) { _assertValue = i & 1; }
+
+ /** Set the number of continuous samples until assert assumed.
+ *
+ * Defaults to 1 (1 * sample frequency).
+ *
+ * @param int The number of continuous samples until assert assumed.
+ */
+ void setSamplesTillAssert(int i) { _samplesTillAssertReload = i; }
+
+ /** Set the number of continuous samples until held assumed.
+ *
+ * Defaults to 50 * sample frequency.
+ *
+ * @param int The number of continuous samples until held assumed.
+ */
+ void setSamplesTillHeld(int i) { _samplesTillHeldReload = i; }
+
+ /** Set the pin mode.
+ *
+ * @see http://mbed.org/projects/libraries/api/mbed/trunk/DigitalInOut#DigitalInOut.mode
+ * @param PinMode m The mode to pass on to the DigitalIn
+ */
+ void mode(PinMode m) { _in->mode(m); }
+
+ /** Attach a callback function
+ *
+ * @code
+ *
+ * DigitalOut led1( LED1 );
+ * PinDetect pin( p30 );
+ *
+ * void myCallback( void ) {
+ * led1 = 1;
+ * };
+ *
+ * main() {
+ * pin.attach_asserted( &myCallback );
+ * }
+ *
+ * @endcode
+ *
+ * Call this function when a pin is asserted.
+ * @param function A C function pointer
+ */
+ void attach_asserted(void (*function)(void)) {
+ _callbackAsserted.attach(function);
+ }
+
+ /** Attach a callback object/method
+ *
+ * @code
+ *
+ * class Bar {
+ * public:
+ * void myCallback( void ) { led1 = 1; }
+ * };
+ *
+ * DigitalOut led1( LED1 );
+ * PinDetect pin( p30 );
+ * Bar bar;
+ *
+ * main() {
+ * pin.attach_asserted( &bar, &Bar::myCallback );
+ * }
+ *
+ * @endcode
+ *
+ * Call this function when a pin is asserted.
+ * @param object An object that conatins the callback method.
+ * @param method The method within the object to call.
+ */
+ template<typename T>
+ void attach_asserted(T *object, void (T::*member)(void)) {
+ _callbackAsserted.attach(object, member);
+ }
+
+ /** Attach a callback function
+ *
+ * @code
+ *
+ * DigitalOut led1( LED1 );
+ * PinDetect pin( p30 );
+ *
+ * void myCallback( void ) {
+ * led1 = 0;
+ * };
+ *
+ * main() {
+ * pin.attach_deasserted( &myCallback );
+ * }
+ *
+ * @endcode
+ *
+ * Call this function when a pin is deasserted.
+ * @param function A C function pointer
+ */
+ void attach_deasserted(void (*function)(void)) {
+ _callbackDeasserted.attach(function);
+ }
+
+ /** Attach a callback object/method
+ *
+ * @code
+ *
+ * class Bar {
+ * public:
+ * void myCallback( void ) { led1 = 0; }
+ * };
+ *
+ * DigitalOut led1( LED1 );
+ * PinDetect pin( p30 );
+ * Bar bar;
+ *
+ * main() {
+ * pin.attach_deasserted( &bar, &Bar::myCallback );
+ * }
+ *
+ * @endcode
+ *
+ * Call this function when a pin is deasserted.
+ * @param object An object that conatins the callback method.
+ * @param method The method within the object to call.
+ */
+ template<typename T>
+ void attach_deasserted(T *object, void (T::*member)(void)) {
+ _callbackDeasserted.attach(object, member);
+ }
+
+ /** Attach a callback function
+ *
+ * @code
+ *
+ * DigitalOut led2( LED2 );
+ * PinDetect pin( p30 );
+ *
+ * void myCallback( void ) {
+ * led2 = 1;
+ * };
+ *
+ * main() {
+ * pin.attach_asserted_held( &myCallback );
+ * }
+ *
+ * @endcode
+ *
+ * Call this function when a pin is asserted and held.
+ * @param function A C function pointer
+ */
+ void attach_asserted_held(void (*function)(void)) {
+ _callbackAssertedHeld.attach(function);
+ }
+
+ /** Attach a callback object/method
+ *
+ * @code
+ *
+ * class Bar {
+ * public:
+ * void myCallback( void ) { led2 = 0; }
+ * };
+ *
+ * DigitalOut led2( LED2 );
+ * PinDetect pin( p30 );
+ * Bar bar;
+ *
+ * main() {
+ * pin.attach_asserted_held( &bar, &Bar::myCallback );
+ * }
+ *
+ * @endcode
+ *
+ * Call this function when a pin is asserted and held.
+ * @param object An object that conatins the callback method.
+ * @param method The method within the object to call.
+ */
+ template<typename T>
+ void attach_asserted_held(T *object, void (T::*member)(void)) {
+ _callbackAssertedHeld.attach(object, member);
+ }
+
+ /** Attach a callback function
+ *
+ * @code
+ *
+ * DigitalOut led3( LED3 );
+ * PinDetect pin( p30 );
+ *
+ * void myCallback( void ) {
+ * led3 = 1;
+ * };
+ *
+ * main() {
+ * pin.attach_deasserted_held( &myCallback );
+ * }
+ *
+ * @endcode
+ *
+ * Call this function when a pin is deasserted and held.
+ * @param function A C function pointer
+ */
+ void attach_deasserted_held(void (*function)(void)) {
+ _callbackDeassertedHeld.attach(function);
+ }
+
+ /** Attach a callback object/method
+ *
+ * @code
+ *
+ * class Bar {
+ * public:
+ * void myCallback( void ) { led3 = 0; }
+ * };
+ *
+ * DigitalOut led3( LED3 );
+ * PinDetect pin( p30 );
+ * Bar bar;
+ *
+ * main() {
+ * pin.attach_deasserted_held( &bar, &Bar::myCallback );
+ * }
+ *
+ * @endcode
+ *
+ * Call this function when a pin is deasserted and held.
+ * @param object An object that conatins the callback method.
+ * @param method The method within the object to call.
+ */
+ template<typename T>
+ void attach_deasserted_held(T *object, void (T::*member)(void)) {
+ _callbackDeassertedHeld.attach(object, member);
+ }
+
+ /** operator int()
+ *
+ * Read the value of the pin being sampled.
+ */
+ operator int() { return _in->read(); }
+
+ /** The Ticker periodic callback function
+ */
+ void isr(void) {
+ int currentState = _in->read();
+
+ if (currentState != _prevState) {
+ if (_samplesTillAssert == 0) {
+ _prevState = currentState;
+ _samplesTillHeld = _samplesTillHeldReload;
+ if (currentState == _assertValue)
+ _callbackAsserted.call();
+ else
+ _callbackDeasserted.call();
+ }
+ else {
+ _samplesTillAssert--;
+ }
+ }
+ else {
+ _samplesTillAssert = _samplesTillAssertReload;
+ }
+
+ if (_samplesTillHeld) {
+ if (_prevState == currentState) {
+ _samplesTillHeld--;
+ if (_samplesTillHeld == 0) {
+ if (currentState == _assertValue)
+ _callbackAssertedHeld.call();
+ else
+ _callbackDeassertedHeld.call();
+ }
+ }
+ else {
+ _samplesTillHeld = 0;
+ }
+ }
+ }
+
+protected:
+ DigitalIn *_in;
+ Ticker *_ticker;
+ int _prevState;
+ int _currentStateCounter;
+ int _sampleTime;
+ int _assertValue;
+ int _samplesTillAssertReload;
+ int _samplesTillAssert;
+ int _samplesTillHeldReload;
+ int _samplesTillHeld;
+ FunctionPointer _callbackAsserted;
+ FunctionPointer _callbackDeasserted;
+ FunctionPointer _callbackAssertedHeld;
+ FunctionPointer _callbackDeassertedHeld;
+};
+
+}; // namespace AjK ends.
+
+using namespace AjK;
+
+#endif