unit_BH1750FVI.hpp

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/*
 * SPDX-FileCopyrightText: 2026 M5Stack Technology CO LTD
 *
 * SPDX-License-Identifier: MIT
 */
#ifndef M5_UNIT_LIGHT_UNIT_BH1750FVI_HPP
#define M5_UNIT_LIGHT_UNIT_BH1750FVI_HPP
 
#include <M5UnitComponent.hpp>
#include <m5_utility/stl/extension.hpp>
#include <m5_utility/container/circular_buffer.hpp>
#include "unit_BH1750FVI_data.hpp"  // Mode, Resolution, MTREG_* constants, Data (with inline lux())
#include <cstdint>
#include <limits>
 
namespace m5 {
namespace unit {
 
namespace bh1750fvi {
 
namespace command {
// Power / reset opcodes
constexpr uint8_t POWER_DOWN{0x00};
constexpr uint8_t POWER_ON{0x01};
constexpr uint8_t RESET{0x07};
 
// Continuous-mode measurement opcodes
constexpr uint8_t CONTINUOUS_H_RES_MODE{0x10};
constexpr uint8_t CONTINUOUS_H_RES_MODE2{0x11};
constexpr uint8_t CONTINUOUS_L_RES_MODE{0x13};
 
// One-time measurement opcodes
constexpr uint8_t ONE_TIME_H_RES_MODE{0x20};
constexpr uint8_t ONE_TIME_H_RES_MODE2{0x21};
constexpr uint8_t ONE_TIME_L_RES_MODE{0x23};  // NOTE: same hex as slave address, not related
 
// MTreg opcodes (bitmask bases; combine with mtreg bits)
constexpr uint8_t CHANGE_MEASUREMENT_TIME_HIGH{0x40};  
constexpr uint8_t CHANGE_MEASUREMENT_TIME_LOW{0x60};   
}  // namespace command
 
}  // namespace bh1750fvi
 
class UnitBH1750FVI : public Component, public PeriodicMeasurementAdapter<UnitBH1750FVI, bh1750fvi::Data> {
    M5_UNIT_COMPONENT_HPP_BUILDER(UnitBH1750FVI, 0x23);
 
public:
    static constexpr uint8_t ALT_ADDRESS{0x5C};
 
    struct config_t {
        bool start_periodic{true};
        bh1750fvi::Resolution resolution{bh1750fvi::Resolution::High};
        uint8_t mtreg{bh1750fvi::MTREG_DEFAULT};
    };
 
    explicit UnitBH1750FVI(const uint8_t addr = DEFAULT_ADDRESS)
        : Component(addr), _data{new m5::container::CircularBuffer<bh1750fvi::Data>(1)}
    {
        auto ccfg        = component_config();
        ccfg.clock       = 400 * 1000U;  // BH1750FVI I2C max clock
        ccfg.stored_size = 8;
        component_config(ccfg);
    }
    virtual ~UnitBH1750FVI()
    {
    }
 
    virtual bool begin() override;
    virtual void update(const bool force = false) override;
 
    inline config_t config() const
    {
        return _cfg;
    }
    inline void config(const config_t& cfg)
    {
        _cfg = cfg;
    }
 
    inline float lux() const
    {
        return !empty() ? latest().lux() : std::numeric_limits<float>::quiet_NaN();
    }
    inline uint16_t raw() const
    {
        return !empty() ? latest().raw : 0;
    }
    inline bh1750fvi::Resolution resolution() const
    {
        return _resolution;
    }
    inline uint8_t mtreg() const
    {
        return _mtreg;
    }
 
 
    inline bool startPeriodicMeasurement()
    {
        return PeriodicMeasurementAdapter<UnitBH1750FVI, bh1750fvi::Data>::startPeriodicMeasurement();
    }
    inline bool startPeriodicMeasurement(const bh1750fvi::Resolution resolution, const uint8_t mtreg)
    {
        return PeriodicMeasurementAdapter<UnitBH1750FVI, bh1750fvi::Data>::startPeriodicMeasurement(resolution, mtreg);
    }
    inline bool stopPeriodicMeasurement()
    {
        return PeriodicMeasurementAdapter<UnitBH1750FVI, bh1750fvi::Data>::stopPeriodicMeasurement();
    }
 
 
    bool measureSingleShot(bh1750fvi::Data& data, const bh1750fvi::Resolution resolution = bh1750fvi::Resolution::High,
                           const uint8_t mtreg = bh1750fvi::MTREG_DEFAULT);
 
 
    bool writeMTreg(const uint8_t mtreg);
 
    bool writeSensitivityFactor(const float factor);
 
    inline uint8_t readMTreg() const
    {
        return _mtreg;
    }
 
 
    bool powerOn();
    bool powerDown();
    bool softReset();
 
protected:
    bool start_periodic_measurement();
    bool start_periodic_measurement(const bh1750fvi::Resolution resolution, const uint8_t mtreg);
    bool stop_periodic_measurement();
 
    bool read_measurement(bh1750fvi::Data& data);
    bool write_opcode(const uint8_t opcode);
    bool write_mtreg_opcodes(const uint8_t mtreg);
    uint8_t opcode_for(const bh1750fvi::Mode mode, const bh1750fvi::Resolution resolution) const;
 
    void apply_interval(const bh1750fvi::Resolution resolution, const uint8_t mtreg);
 
    M5_UNIT_COMPONENT_PERIODIC_MEASUREMENT_ADAPTER_HPP_BUILDER(UnitBH1750FVI, bh1750fvi::Data);
 
protected:
    std::unique_ptr<m5::container::CircularBuffer<bh1750fvi::Data>> _data{};
    config_t _cfg{};
    bh1750fvi::Resolution _resolution{bh1750fvi::Resolution::High};
    uint8_t _mtreg{bh1750fvi::MTREG_DEFAULT};
};
 
}  // namespace unit
}  // namespace m5
 
#endif