Unit BMM350 Arduino Tutorial

#include <M5Unified.h>
#include <M5UnitUnified.h>
#include <M5UnitUnifiedIMU.h>

m5::unit::UnitUnified units;
m5::unit::UnitBMM350 bmm350{0x14};
m5::imu::imu_convert_param_t convert_param{};

constexpr uint16_t COLOR_BG     = TFT_BLACK;
constexpr uint16_t COLOR_CARD   = TFT_BLACK;
constexpr uint16_t COLOR_BORDER = TFT_BLACK;
constexpr uint16_t COLOR_ACCENT = TFT_CYAN;
constexpr uint16_t COLOR_MUTED  = TFT_DARKGREY;
constexpr uint16_t COLOR_GOOD   = 0x5CE0;

void drawHeader(bool connected) {
    M5.Display.fillScreen(COLOR_BG);
    M5.Display.setTextSize(1);
    M5.Display.setTextColor(TFT_CYAN, COLOR_CARD);
    M5.Display.setCursor(12, 8);
    M5.Display.print("UNIT BMM350");
    M5.Display.setTextSize(1);
    M5.Display.setTextColor(connected ? TFT_GREEN : TFT_ORANGE, COLOR_CARD);
    M5.Display.setCursor(220, 8);
    M5.Display.print(connected ? "READY" : "WAIT");
    M5.Display.fillCircle(304, 18, 5, connected ? COLOR_GOOD : TFT_ORANGE);
}

void drawStatus(const char* message, uint16_t color) {
    M5.Display.fillScreen(COLOR_BG);
    drawHeader(false);
    M5.Display.setTextSize(1);
    M5.Display.setTextColor(color, COLOR_BG);
    M5.Display.setCursor(12, 76);
    M5.Display.print(message);
    M5.Display.setTextSize(1);
    M5.Display.setTextColor(COLOR_MUTED, COLOR_BG);
    M5.Display.setCursor(12, 112);
    M5.Display.print("I2C bus / sensor status");
}

void drawData(float mx, float my, float mz) {
    M5.Display.startWrite();
    // Clear the block so old values do not leave ghosts.
    M5.Display.fillRect(0, 56, 320, 120, TFT_BLACK);
    M5.Display.setTextSize(1);
    M5.Display.setTextColor(COLOR_ACCENT, COLOR_CARD);
    M5.Display.setCursor(22, 68);
    M5.Display.print("MAGNETIC FIELD");
    M5.Display.setTextColor(COLOR_MUTED, COLOR_CARD);
    M5.Display.setCursor(22, 84);
    M5.Display.print("COMPENSATED OUTPUT  /  uT");
    M5.Display.setTextColor(TFT_WHITE, COLOR_CARD);
    M5.Display.setTextSize(1);
    M5.Display.setCursor(22, 108);
    M5.Display.printf("X  % 8.2f   ", mx);
    M5.Display.setCursor(22, 132);
    M5.Display.printf("Y  % 8.2f   ", my);
    M5.Display.setCursor(22, 156);
    M5.Display.printf("Z  % 8.2f   ", mz);
    M5.Display.setTextSize(1);
    M5.Display.setTextColor(COLOR_MUTED, COLOR_BG);
    M5.Display.setCursor(12, 218);
    M5.Display.print("LIVE  |  500 ms  |  I2C 400 kHz");
    M5.Display.endWrite();
}

void setup() {
    Serial.begin(115200);
    const uint32_t serial_start = millis();
    while (!Serial && millis() - serial_start < 3000) {
        delay(10);
    }
    Serial.println("Starting Unit BMM350...");

    auto config = M5.config();
    M5.begin(config);
    M5.Display.setFont(&fonts::FreeSansBold9pt7b);
    M5.Display.setTextSize(1);
    M5.Display.setRotation(1);
    M5.Display.setTextWrap(false, false);
    drawStatus("Initializing...", COLOR_ACCENT);

    auto cfg = bmm350.component_config();
    cfg.clock = 400000;
    bmm350.component_config(cfg);

    if (!M5.Ex_I2C.begin() || !units.add(bmm350, M5.Ex_I2C) || !units.begin()) {
        while (true) {
            Serial.println("Unit BMM350 not found. Check wiring or I2C address.");
            drawStatus("Sensor not found", TFT_ORANGE);
            delay(1000);
        }
    }

    bmm350.imuConvertParam(convert_param);
    Serial.println("Unit BMM350 ready, address: 0x14");
    drawHeader(true);
}

void loop() {
    M5.update();
    units.update();

    static uint32_t last_output = 0;
    if (millis() - last_output < 500) {
        return;
    }
    last_output = millis();

    m5::imu::imu_raw_data_t raw{};
    static bool waiting_shown = false;
    if (m5::imu::any(bmm350.readImuRaw(raw))) {
        waiting_shown = false;
        const float mx = raw.mag[0] * convert_param.mag_res;
        const float my = raw.mag[1] * convert_param.mag_res;
        const float mz = raw.mag[2] * convert_param.mag_res;
        Serial.printf("Magnetic field: X %.2f, Y %.2f, Z %.2f uT\n",
                      mx, my, mz);
        drawData(mx, my, mz);
    } else {
        if (!waiting_shown) {
            waiting_shown = true;
            Serial.println("Waiting for Unit BMM350 data...");
            drawStatus("Waiting for data...", COLOR_ACCENT);
        }
    }
}