Merge pull request #171 from cogip/170-motion-control-add-c++-encoder…

…-class

170 motion control add c++ encoder class

lib/encoder/Makefile

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+include $(RIOTBASE)/Makefile.base

lib/encoder/Makefile.dep

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+# Board features required
+FEATURES_REQUIRED += periph_qdec

lib/encoder/Makefile.include

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+USEMODULE_INCLUDES_encoder := $(LAST_MAKEFILEDIR)/include
+USEMODULE_INCLUDES += $(USEMODULE_INCLUDES_encoder)

lib/encoder/include/encoder/EncoderInterface.hpp

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+#pragma once
+
+#include <cstdint>
+
+#include "etl/math_constants.h"
+
+namespace cogip {
+
+namespace encoder {
+
+enum class EncoderMode : uint8_t {
+    /// With X1 encoding, either the rising (aka leading) or the falling (aka following) edge of
+    /// channel A is counted. If channel A leads channel B, the rising edge is counted, and the
+    /// movement is forward, or clockwise. Conversely, if channel B leads channel A, the falling edge
+    /// is counted, and the movement is backwards, or counterclockwise.
+    ENCODER_MODE_X1 = 0,
+
+    /// When X2 encoding is used, both the rising and falling edges of channel A are counted. This
+    /// doubles the number of pulses that are counted for each rotation or linear distance, which in
+    /// turn doubles the encoder’s resolution.
+    ENCODER_MODE_X2 = 1,
+
+    /// X4 encoding goes one step further, to count both the rising and falling edges of both
+    /// channels A and B, which quadruples the number of pulses and increases resolution by four
+    /// times.
+    ENCODER_MODE_X4 = 2,
+};
+
+class EncoderInterface {
+public:
+    ///
+    /// @brief Construct a new Encoder Interface object
+    /// @note Encoder pulse per revolution must be set according to chosen mode
+    /// eg. For a 2500 PPR encoder:
+    ///              - ENCODER_MODE_X1 -> pulse_per_rev = 2500
+    ///              - ENCODER_MODE_X2 -> pulse_per_rev = 5000
+    ///              - ENCODER_MODE_X4 -> pulse_per_rev = 10000
+    /// @param mode 
+    /// @param pulse_per_rev 
+    ///
+    EncoderInterface(EncoderMode mode, int32_t pulse_per_rev): mode_(mode), pulse_per_rev_(pulse_per_rev) {}
+
+    ///
+    /// @brief Get the pulses counted by the encoder since the last call.
+    ///
+    /// @return int32_t int32_t counter value in ticks
+    ///
+    virtual int32_t read_and_reset() = 0;
+
+    ///
+    /// @brief Reset encoder counter
+    ///
+    virtual void reset() = 0;
+
+    /// 
+    /// @brief Get the angle measured by the encoder since the last call.
+    ///
+    /// @return double traveled angle since last call (rad).
+    ///
+    double get_angle_and_reset() { return ((double)read_and_reset() / (double)pulse_per_rev_) * etl::math::pi; }
+
+protected:
+    const EncoderMode mode_;
+    const int32_t pulse_per_rev_;
+};
+
+} /// namespace encoder
+
+} /// namespace cogip
+
+/// @}

lib/encoder/include/encoder/EncoderQDEC.hpp

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+#pragma once
+
+#include "etl/math_constants.h"
+
+// RIOT includes
+#include "periph/qdec.h"
+
+// Module includes
+#include "EncoderInterface.hpp"
+namespace cogip {
+
+namespace encoder {
+
+class EncoderQDEC : public EncoderInterface {
+public:
+
+    ///
+    /// @brief Construct a new Encoder object
+    /// @note Encoder pulse per revolution must be set according to chosen mode
+    /// eg. For a 2500 PPR encoder:
+    ///              - ENCODER_MODE_X1 -> pulse_per_rev = 2500
+    ///              - ENCODER_MODE_X2 -> pulse_per_rev = 5000
+    ///              - ENCODER_MODE_X4 -> pulse_per_rev = 10000
+    /// @param mode 
+    /// @param pulse_per_rev 
+    ///
+    explicit EncoderQDEC(uint8_t id, EncoderMode mode, int32_t pulse_per_rev): EncoderInterface(mode, pulse_per_rev), id_(id) {}
+
+    /// 
+    /// @brief Setup encoder
+    ///
+    /// @return int negative on error. 0 on succes
+    ///
+    int setup()
+    {
+        qdec_t qdec;
+        qdec_mode_t qdec_mode;
+
+        qdec = QDEC_DEV(id_);
+
+        switch (mode_) {
+        case EncoderMode::ENCODER_MODE_X1:
+            qdec_mode = QDEC_X1;
+            break;
+        case EncoderMode::ENCODER_MODE_X2:
+            qdec_mode = QDEC_X2;
+            break;
+        case EncoderMode::ENCODER_MODE_X4:
+            qdec_mode = QDEC_X4;
+            break;
+        default:
+            printf("Invalid QDEC mode (%u)\n", id_);
+            return -1;
+        }
+
+        /* Setup QDEC peripheral */
+        int error = qdec_init(qdec, qdec_mode, NULL, NULL);
+        if (error) {
+            printf("QDEC %u not initialized, error=%d !!!\n", id_, error);
+        }
+
+        return error;
+    }
+
+    /// 
+    /// @brief Get the pulses counted by the encoder since the last call.
+    ///
+    /// @return int32_t counter value in ticks
+    ///
+    int32_t read_and_reset() override { return qdec_read_and_reset(id_); }
+
+    /// 
+    /// @brief Reset encoder counter
+    ///
+    ///
+    void reset() override { (void)read_and_reset(); };
+
+private:
+    uint8_t id_;
+};
+
+} /// namespace encoder
+
+} /// namespace cogip
+
+/// @}