Diff: QuadEnc.hpp

Revision:

0:9afc272fa65f

Child:

5:e00cc0dab1c7

diff -r 000000000000 -r 9afc272fa65f QuadEnc.hpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/QuadEnc.hpp	Fri Jun 24 21:03:20 2016 +0000
@@ -0,0 +1,83 @@
+/**
+ * @class QuadEnc
+ * @date June 2nd, 2016
+ * @author Weimen Li
+ * @brief Header file for a class which encapsulates a quadrature encoder.
+ * @remark The current implementation does not give the Quadrature Encoder maximum
+ * priority, but it really should.
+ */
+
+#ifndef QUADENC_H_
+#define QUADENC_H_
+#include "mbed.h"
+
+class QuadEnc {
+public:
+    /**
+     * @brief Constructor for the QuadEnc object.
+     * @param ChannelA The pin Channel A is connected to.
+     * @param ChannelB The pin Channel B is connected to.
+     * @param CPR The number of counts per revolution of the encoder.
+     */
+    QuadEnc(PinName ChannelA, PinName ChannelB, float CPR);
+    virtual ~QuadEnc();
+
+    /**
+     * @brief Returns true when a new encoder count has been seen.
+     * @returns Whether a new encoder count has been seen.
+     * @remark Sets the hasNewCount flag to false after being called.
+     */
+    bool hasNewCount();
+    /**
+     * @brief Returns the current encoder count.
+     * @returns The current encoder count.
+     * @remark Declared to be inline for greater performance.
+     */
+    inline int32_t getCount() {
+        // Generally, we would disable interrupts to avoid corruption here.
+        // However, the returned value is the word size of the processor, so
+        // It should be safe. Additionally, any corruption may only happen on the LSB.
+        return count;
+    }
+    
+    /**
+     * @brief Returns the number of revolutions that have been counted.
+     * @returns The number of revolutions that have been counted.
+     */
+    float getRevs();
+
+    /**
+     * @brief Resets the internal state variables of the encoder.
+     * @returns void
+     */
+    void reset();
+private:
+     /// The current encoder count since the program started.
+    volatile int32_t count;
+     /// Whether the encoder has a new count.
+    volatile bool bHasNewCount;
+    /// The number of counts per revolution.
+    const float CPR;
+    
+    /// Digital Input for Channel A.
+    DigitalIn ChannelAIn;
+    /// Digital Input for Channel B.
+    DigitalIn ChannelBIn;
+    
+    /// Interrupt Object for Channel A.
+    InterruptIn ChannelAInter;
+    /// Interrupt Object for Channel B.
+    InterruptIn ChannelBInter;
+
+    /// Member Function ISR to be called when a change is detected on the channel pins.
+    void QuadEncISR();
+
+    /// The previous encoder count.
+    int32_t prevCount;
+    /// The previous number of revolutions.
+    float prevRevs;
+    /// The raw encoder reading.
+    uint8_t enc_val;
+};
+
+#endif /* QUADENC_H_ */