Diff: Encoder.h

Revision:

0:d510e8063ad1

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Encoder.h	Tue Mar 15 08:30:32 2016 +0000
@@ -0,0 +1,87 @@
+#ifndef ENCODER_H_INCLUDED
+#define ENCODER_H_INCLUDED
+
+/** Class to handle a rotary encoder
+ *  The lib is interrupt based, therefore no update functions have to be called.
+ *  Example usage:
+ *  @code
+ *
+ *  #include "mbed.h"
+ *  #include "Encoder.h"
+ *
+ *  RotaryEncoder encoder(D3, D4);
+ *
+ *  int main()
+ *  {
+ *      while(1)
+ *      {
+ *          int pos = encoder.position();
+ *          wait(1.0f);
+ *      }
+ *  }
+ *  @endcode
+ */
+class RotaryEncoder {
+public:
+    RotaryEncoder(PinName outa, PinName outb)
+        : position_(0), delta_(0),
+          inta_(outa), intb_(outb), outa_(outa), outb_(outb) {
+        outa_.mode(PullUp);
+        outb_.mode(PullUp);
+        inta_.rise(this, &RotaryEncoder::handleIntA);
+        inta_.fall(this, &RotaryEncoder::handleIntA);
+        intb_.rise(this, &RotaryEncoder::handleIntB);
+        intb_.fall(this, &RotaryEncoder::handleIntB);
+    }
+
+    /** Returns the overall position of the encoder
+     */
+    int position() {
+        return position_;
+    }
+
+    /** Returns the encoders change since the last call to this function
+     */
+    int delta() {
+        int d = delta_;
+        delta_ = 0;
+        return d;
+    }
+
+private:
+
+    // A  = B --> Clockwise
+    // A /= B --> Counter clockwise
+    void handleIntA() {
+        if (outa_ == outb_) {
+            increment(1);
+        } else {
+            increment(-1);
+        }
+    }
+
+    // A  = B --> Counter clockwise
+    // A /= B --> Clockwise
+    void handleIntB() {
+        if (outa_ == outb_) {
+            increment(-1);
+        } else {
+            increment(1);
+        }
+    }
+
+    void increment(int i) {
+        position_ += i;
+        delta_ += i;
+    }
+
+    int position_;
+    int delta_;
+
+    InterruptIn inta_;
+    InterruptIn intb_;
+    DigitalIn outa_;
+    DigitalIn outb_;
+};
+
+#endif /* ENCODER_H_INCLUDED */