Revision 0:50aae578cb89, committed 2015-11-23

Comitter:

electromotivated

Date:

Mon Nov 23 02:44:15 2015 +0000

Commit message:

Basic encoder library upload;

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/QEI.cpp	Mon Nov 23 02:44:15 2015 +0000
@@ -0,0 +1,21 @@
+#include "QEI.h"
+
+QEI::QEI(PinName encA, PinName encB): _encA(encA), _encB(encB){
+    _encA.mode(PullUp);
+    _encA.rise(this, &QEI::callback);
+    
+    _encB.mode(PullUp);
+}
+
+long QEI::read(){
+    return count;
+}
+
+void QEI::reset(){
+    count = 0;
+}
+
+void QEI::callback(){
+    if(_encB) count--;  // CCW count
+    else count++;       // CW count    
+}
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/QEI.h	Mon Nov 23 02:44:15 2015 +0000
@@ -0,0 +1,46 @@
+#ifndef QEI_H
+#define QEI_H
+
+/*
+    Basic Quadrature Encoder Interface (QEI) Class.
+    
+    TODO: Expand to allow setting of quad mode, i.e. count on 
+    rising of A only, rising and falling of A, rising and falling 
+    of both A and B. (Forgot what these modes are called but 
+    can be found in literature online.) 
+*/
+
+#include "mbed.h"
+
+class QEI{
+    public:
+        /*
+            Constructor for QEI objects
+            @param encA     The mbed pin that encoder input A is on
+            @param encB     The mbed pin that encoder input B is on
+        */
+        QEI(PinName encA, PinName encB);
+        /*
+            read() returns total number of counts of the encoder.
+            Count can be +/- and indicates the overall direction,
+            (+): CW (-): CCW
+            @return     The toltal number of counts of the encoder.
+            
+            TODO: Add Conversion Overload for this method
+        */
+        long read();
+        /*
+            reset() clears the counter to 0. 
+        */
+        void reset();
+    private:
+        long count;         // Total number of counts since start.
+        InterruptIn _encA;  // Encoder A interrupt pin
+        DigitalIn _encB;    // Encoder B input pin
+        /*
+            Increments/Decrements count on interrrupt.
+        */
+        void callback();    // Interrupt callback function
+};
+
+#endif
\ No newline at end of file