MotionController.hpp

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#pragma once
 
#include <cstdint>
 
enum class MotionControllerError {
    NONE,  
    INVALID_ARGUMENT,  
    NOT_INITIALISED,  
    DEVICE_OPEN_FAILED,  
    DEVICE_SELECT_FAILED,  
    DEVICE_IO_FAILED  
};
 
enum class MotionOutputState {
    UNINITIALISED,  
    DISABLED,  
    ENABLED,  
    FAULT  
};
 
struct MotionChannelMap {
    std::uint8_t base{0};  
    std::uint8_t lower{4};  
    std::uint8_t upper{8};  
    std::uint8_t gripper{12};  
};
 
struct MeArmJointTargets {
    std::uint16_t base_ticks{0};  
    std::uint16_t lower_ticks{0};  
    std::uint16_t upper_ticks{0};  
    std::uint16_t gripper_ticks{0};  
};
 
class MotionController {
public:
    static constexpr std::uint8_t kServoCount = 4;  
    static constexpr std::uint8_t kPca9685ChannelCount = 16;  
    static constexpr std::uint16_t kMaxPulseTicks = 4095;  
 
    MotionController() noexcept;
 
    ~MotionController() noexcept;
 
    MotionController(const MotionController&) = delete;
    MotionController& operator=(const MotionController&) = delete;
    MotionController(MotionController&&) = delete;
    MotionController& operator=(MotionController&&) = delete;
 
    bool initialise(
        const char* i2c_device_path = "/dev/i2c-1",
        std::uint8_t device_address = 0x40,
        float pwm_frequency_hz = 50.0f,
        MotionChannelMap channel_map = {}) noexcept;
 
    bool setTargets(const MeArmJointTargets& targets) noexcept;
 
    void freeze() noexcept;
 
    bool enable() noexcept;
 
    void shutdown() noexcept;
 
    bool isInitialised() const noexcept;
 
    bool isEnabled() const noexcept;
 
    bool isFrozen() const noexcept;
 
    MotionOutputState outputState() const noexcept;
 
    MotionControllerError lastError() const noexcept;
 
    const char* lastErrorString() const noexcept;
 
private:
    bool configurePca9685(float pwm_frequency_hz) noexcept;
    bool writeTargetsToHardware(const MeArmJointTargets& targets) noexcept;
    bool writeChannelPulse(std::uint8_t channel, std::uint16_t pulse_ticks) noexcept;
    bool writeRegister(std::uint8_t reg, std::uint8_t value) noexcept;
    bool writeRegisters(std::uint8_t start_reg,
                        const std::uint8_t* values,
                        std::uint8_t value_count) noexcept;
    bool setAllOutputsEnabled(bool enabled) noexcept;
    bool hasValidChannelMap(const MotionChannelMap& channel_map) const noexcept;
    void setFault(MotionControllerError error) noexcept;
 
    int i2c_fd_;
    MotionChannelMap channel_map_;
    MeArmJointTargets cached_targets_;
    MotionOutputState output_state_;
    MotionControllerError last_error_;
    bool frozen_;
};