New Button Sample

delta time passed to the task wasn't task specific, fixed
if delta time is large compared to task update time, it could end
rolling over, fixed by checking and just skipping to the next frame

Task.h

@@ -15,8 +15,6 @@ See GNU Lesser General Public License at <http://www.gnu.org/licenses/>.
 #ifndef TASK_H
 #define TASK_H
 
-
-
 #if (ARDUINO >= 100)
 #include <Arduino.h>
 #else

TaskManager.cpp

@@ -118,11 +118,22 @@ uint32_t TaskManager::ProcessTasks(uint32_t deltaTimeMs)
         {
             if (pIterate->remainingTimeMs <= deltaTimeMs)
             {
+                // calc per task delta time
+                uint32_t taskDeltaTime = max(1, ((pIterate->initialTimeMs - pIterate->remainingTimeMs) + deltaTimeMs) - 1);
+
+                pIterate->OnUpdate(taskDeltaTime);
+
                 // add the initial time so we don't loose any remainders
                 pIterate->remainingTimeMs += pIterate->initialTimeMs;
-                pIterate->OnUpdate(deltaTimeMs);
+
+                // if we are still less than delta time, things are running slow
+                // so push to the next update frame
+                if (pIterate->remainingTimeMs <= deltaTimeMs)
+                {
+                    pIterate->remainingTimeMs = deltaTimeMs + 1;
+                }
             }
-                
+
             pIterate->remainingTimeMs -= deltaTimeMs;
 
             if (pIterate->remainingTimeMs < nextWakeTimeMs)

examples/ButtonTask/ButtonTask.h

@@ -0,0 +1,72 @@
+// button should be attached to the pin, and when pressed, it should connect the pin to ground
+
+enum ButtonState
+{
+    ButtonState_Pressed,
+    ButtonState_Released
+};
+
+class ButtonTask : public Task
+{
+public:
+    typedef void(*action)(ButtonState state);
+
+    ButtonTask(action function, uint8_t pin) :
+        Task(3), // check every three millisecond, 1-10 ms should be ok
+        _buttonPin(pin),
+        _lastValue(HIGH),
+        _state(ButtonState_Released),
+        _callback(function)
+    { };
+
+private:
+    static const uint8_t _debouceMs = 50; // (30-100) are good values
+    const uint8_t _buttonPin;
+    const action _callback;
+    uint8_t _lastValue;
+    uint8_t _debouceTimer;
+    ButtonState _state;
+
+    virtual void OnStart()
+    {
+        pinMode(_buttonPin, INPUT_PULLUP);
+    }
+
+    virtual void OnUpdate(uint32_t deltaTimeMs)
+    {
+        uint8_t value = digitalRead(_buttonPin);
+
+        if (value != _lastValue)
+        {
+            _lastValue = value;
+            if (value == LOW)
+            {
+                // just read button down
+                _debouceTimer = _debouceMs;
+            }
+            else if (_state == ButtonState_Pressed)
+            {
+                // triggered released
+                _state = ButtonState_Released;
+                _callback(_state);
+            }
+        }
+        else
+        {
+            if (value == LOW && _state == ButtonState_Released)
+            {
+                // still button down
+                if (deltaTimeMs >= _debouceTimer)
+                {
+                    // triggered press
+                    _state = ButtonState_Pressed;
+                    _callback(_state);
+                }
+                else
+                {
+                    _debouceTimer -= deltaTimeMs;
+                }
+            }
+        }
+    }
+};

examples/ButtonTask/ButtonTask.ino

@@ -0,0 +1,67 @@
+// ButtonTask
+// This demonstrates the use of the custom Task object feature of Task library
+// It will instance two custom ButtonTasks to monitor two different pins and call back
+// when they change state; with debouce support
+// This requires two momentary buttons attached between pins 4 & 5 and ground 
+// One button will turn on the on board led when it is pressed down,
+// the other button turn off the on board led when it is released
+
+// Pin 13 has an LED connected on most Arduino boards.
+#define LedPin 13
+#define OnButtonPin 4
+#define OffButtonPin 5
+
+// include libraries
+#include <Task.h>
+
+// include sub files
+#include "ButtonTask.h"
+
+TaskManager taskManager;
+
+ButtonTask onButton(OnButtonChanged, OnButtonPin); 
+ButtonTask offButton(OffButtonChanged, OffButtonPin); 
+
+uint8_t onButtonCount = 0;
+uint8_t offButtonCount = 0;
+
+void setup()
+{
+    Serial.begin(57600);
+    pinMode(LedPin, OUTPUT);
+    taskManager.StartTask(&onButton); 
+    taskManager.StartTask(&offButton); 
+
+    Serial.println("Running...");
+}
+
+void loop()
+{
+    taskManager.Loop();
+}
+
+void OnButtonChanged(ButtonState state)
+{
+    // apply on press
+    if (state == ButtonState_Pressed)
+    {
+        digitalWrite(LedPin, HIGH);   // turn the LED on (HIGH is the voltage level)
+
+        onButtonCount++;
+        Serial.print("OnCount = ");
+        Serial.println(onButtonCount);
+    }
+}
+
+void OffButtonChanged(ButtonState state)
+{
+    // apply on release
+    if (state == ButtonState_Released)
+    {
+        digitalWrite(LedPin, LOW);   // turn the LED off (LOW is the voltage level)
+
+        offButtonCount++;
+        Serial.print("OffCount = ");
+        Serial.println(offButtonCount);
+    }
+}