unit_bmi270_aux_bmm150.hpp

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/*
 * SPDX-FileCopyrightText: 2026 M5Stack Technology CO LTD
 *
 * SPDX-License-Identifier: MIT
 */
#ifndef M5_UNIT_IMU_UNIT_UNIT_BMI270_AUX_BMM150_HPP
#define M5_UNIT_IMU_UNIT_UNIT_BMI270_AUX_BMM150_HPP
 
#include "unit_bmi270.hpp"
 
namespace m5 {
namespace unit {
 
class UnitBMI270AuxBMM150 : public UnitBMI270 {
    M5_UNIT_COMPONENT_HPP_BUILDER(UnitBMI270AuxBMM150, 0x69);
 
public:
    struct config_t : public UnitBMI270::config_t {
        bmm150::Preset aux_mag_preset{bmm150::Preset::Regular};
    };
 
    explicit UnitBMI270AuxBMM150(const uint8_t addr = DEFAULT_ADDRESS);
    virtual ~UnitBMI270AuxBMM150()
    {
    }
 
    virtual bool begin() override;
 
    config_t config() const
    {
        // Only aux_mag_preset is kept here; the inherited fields are re-read from the base, which
        // updates its own copy from writeAccelRange()/writeGyroRange()/start_periodic_measurement()
        config_t cfg                            = _cfg_aux_bmm150;
        static_cast<UnitBMI270::config_t&>(cfg) = UnitBMI270::config();
        return cfg;
    }
    void config(const config_t& cfg)
    {
        _cfg_aux_bmm150 = cfg;
        UnitBMI270::config(cfg);
    }
 
    virtual m5::imu::Capability imuSpec() const override
    {
        using m5::imu::Capability;
        const auto base = Capability::Accel | Capability::Gyro | Capability::Temp;
        return _aux_mag ? (base | Capability::Mag) : base;
    }
    virtual void imuConvertParam(m5::imu::imu_convert_param_t& out) const override;
 
    bool sleep() override;
 
 
    bool writeAuxMagPreset(const bmm150::Preset preset);
    bool writeAuxMagRepetition(const uint8_t rep_xy, const uint8_t rep_z);
    bool readAuxMagRepetition(uint8_t& rep_xy, uint8_t& rep_z) const;
 
protected:
    // Base configuration, then probe and configure the AUX BMM150.
    // A probe failure is not an error: it just means this board has no magnetometer on the
    // interface, so it is switched back off and measurement continues with 6 axes. An
    // AUX mag repetition the fixed poll rate cannot keep up with *is* an error, and is rejected
    // before any register is touched.
    virtual bool start_periodic_measurement(const bmi270::AccelRange accel_range, const bmi270::GyroRange gyro_range,
                                            const bmi270::AccelODR accel_odr, const bmi270::GyroODR gyro_odr,
                                            const bmi270::FilterPerf accel_filter_perf,
                                            const bmi270::AccelBwp accel_bwp, const bmi270::FilterPerf gyro_filter_perf,
                                            const bmi270::GyroBwp gyro_bwp) override;
    virtual bool read_sensor_burst(bmi270::Data& d) override;
 
    enum class AuxDetect : uint8_t {
        Unknown,  
        Absent,   
        Present,  
    };
 
    // AUX support, in the three stages start_periodic_measurement() drives them:
    //
    //   setup mode -> detect (only while Unknown) -> data mode
    //
    // On success the interface is left in data mode, where the BMI270 auto-polls the BMM150 at 25Hz
    // into REG_DATA_0..REG_DATA_7.
 
    // Drives the three stages, skipping the detection once it has an answer. False means this unit
    // runs as a plain 6-axis BMI270, which on most boards is the expected outcome, not a failure
    bool setup_aux_bmm150();
    // Switches the interface on and into manual (single-register) access, so the BMM150's own
    // registers can be reached with aux_read_register8()/aux_write_register8()
    bool aux_enter_setup_mode();
    // Resets the BMM150, checks its chip ID and reads its factory trim into _mag_trim. Requires
    // setup mode. Returning false is the normal outcome on a board that wires nothing here
    bool aux_detect_bmm150();
    // Applies the repetition, starts the BMM150's normal mode and hands the interface over to the
    // BMI270's auto-poll. Requires setup mode and a preceding successful detection
    bool aux_enter_data_mode();
    // Polls REG_STATUS.aux_busy (bit2) until clear; gates every AUX manual transaction below
    bool aux_wait_ready();
    bool aux_write_register8(const uint8_t reg, const uint8_t val);
    bool aux_read_register8(const uint8_t reg, uint8_t& out);
    // Manual burst read of 8 bytes starting at a BMM150 register, via the AUX bridge
    bool aux_read_burst8(const uint8_t bmm150_reg, std::array<uint8_t, 8>& out);
    // Reads the BMM150 factory trim (registers 0x5D-0x71) through 3 overlapping 8 byte AUX
    // bursts (0x5D/0x65/0x6A) and maps them the same way as UnitBMM150::read_trim()
    bool aux_read_trim(bmm150::trim_t& trim);
 
private:
    // Only the aux_mag_preset field is authoritative here -- config() refreshes the inherited ones
    // from the base rather than reading them back out of this copy
    config_t _cfg_aux_bmm150{};
    // Live state, seeded from _cfg_aux_bmm150 by begin() and thereafter owned by
    // writeAuxMagRepetition(); what aux_enter_data_mode() writes to the magnetometer
    uint8_t _aux_rep_xy{};
    uint8_t _aux_rep_z{};
    // Does this board carry a BMM150? Answered once, kept across stop/start; invalidated by
    // begin() (soft reset wipes the AUX setup) and sleep() (suspend resets the magnetometer)
    AuxDetect _aux_detect{AuxDetect::Unknown};
    bool _aux_mag{false};        // True while the bridge is in data mode and delivering mag samples
    bmm150::trim_t _mag_trim{};  // Factory trim read via the AUX bridge, valid once _aux_detect is Present
};
 
}  // namespace unit
}  // namespace m5
#endif