BMM350 Unit

该库是 BMM350 Unit 的驱动程序，用于读取三轴 BMM350 磁力计数据。

支持以下产品：

UiFlow2 应用示例

读取磁场和航向角

在 UiFlow2 中打开 cores3_unit_bmm350_example.m5f2 项目。

此示例显示航向角、X/Y/Z 三轴磁场值和传感器温度。点击校准按钮开始采样，旋转 Unit 使其经过三个轴向，然后再次点击按钮完成校准。

UiFlow2 图形化代码块：

校准至少需要 32 个样本，并且每个轴的磁场范围至少达到 10 uT。如果范围不足，示例会保留之前的校准结果，并提示重新校准。

MicroPython 应用示例

读取磁场和航向角

此示例使用 CoreS3 Unit A 的 I2C 接口，持续刷新图形界面中的当前磁场、温度和航向角。

MicroPython 代码块：

# SPDX-FileCopyrightText: 2026 M5Stack Technology CO LTD
#
# SPDX-License-Identifier: MIT

import os, sys, io
import M5
from M5 import *
import m5ui
import lvgl as lv
from unit import BMM350Unit
from hardware import Pin
from hardware import I2C
import time


page0 = None
label_title = None
label_status = None
label_heading = None
label_x = None
label_y = None
label_z = None
label_temperature = None
button_calibrate = None
i2c0 = None
bmm350_0 = None
magnetic = None
calibration_result = None
temperature = None
heading = None
mag_x = None
mag_y = None
mag_z = None


def button_calibrate_short_clicked_event(event_struct):
    global \
        page0, \
        label_title, \
        label_status, \
        label_heading, \
        label_x, \
        label_y, \
        label_z, \
        label_temperature, \
        button_calibrate, \
        i2c0, \
        bmm350_0, \
        magnetic, \
        calibration_result, \
        temperature, \
        heading, \
        mag_x, \
        mag_y, \
        mag_z
    if bmm350_0.is_calibrating():
        try:
            calibration_result = bmm350_0.stop_calibration()
            label_status.set_text(str("Complete"))
            button_calibrate.set_btn_text(str("Calibrate"))
        except:
            label_status.set_text(str("Incomplete"))
            button_calibrate.set_btn_text(str("Retry"))

    else:
        if not (bmm350_0.is_calibrating()):
            bmm350_0.start_calibration()
            label_status.set_text(str("Calibrating"))
            button_calibrate.set_btn_text(str("Finish"))


def button_calibrate_event_handler(event_struct):
    global \
        page0, \
        label_title, \
        label_status, \
        label_heading, \
        label_x, \
        label_y, \
        label_z, \
        label_temperature, \
        button_calibrate, \
        i2c0, \
        bmm350_0, \
        magnetic, \
        calibration_result, \
        temperature, \
        heading, \
        mag_x, \
        mag_y, \
        mag_z
    event = event_struct.code
    if event == lv.EVENT.SHORT_CLICKED and True:
        button_calibrate_short_clicked_event(event_struct)
    return


def setup():
    global \
        page0, \
        label_title, \
        label_status, \
        label_heading, \
        label_x, \
        label_y, \
        label_z, \
        label_temperature, \
        button_calibrate, \
        i2c0, \
        bmm350_0, \
        magnetic, \
        calibration_result, \
        temperature, \
        heading, \
        mag_x, \
        mag_y, \
        mag_z

    M5.begin()
    Widgets.setRotation(0)
    m5ui.init()
    page0 = m5ui.M5Page(bg_c=0x111820)
    label_title = m5ui.M5Label(
        "BMM350 Unit",
        x=76,
        y=9,
        text_c=0x58D6C7,
        bg_c=0x111820,
        bg_opa=0,
        font=lv.font_montserrat_24,
        parent=page0,
    )
    label_status = m5ui.M5Label(
        "Ready",
        x=215,
        y=138,
        text_c=0x95A4B3,
        bg_c=0x111820,
        bg_opa=0,
        font=lv.font_montserrat_14,
        parent=page0,
    )
    label_heading = m5ui.M5Label(
        "Heading: ---.-",
        x=86,
        y=70,
        text_c=0xFFFFFF,
        bg_c=0x111820,
        bg_opa=0,
        font=lv.font_montserrat_24,
        parent=page0,
    )
    label_x = m5ui.M5Label(
        "X: ----.-- uT",
        x=10,
        y=140,
        text_c=0xFF6B6B,
        bg_c=0x111820,
        bg_opa=0,
        font=lv.font_montserrat_14,
        parent=page0,
    )
    label_y = m5ui.M5Label(
        "Y: ----.-- uT",
        x=10,
        y=160,
        text_c=0x58D68D,
        bg_c=0x111820,
        bg_opa=0,
        font=lv.font_montserrat_14,
        parent=page0,
    )
    label_z = m5ui.M5Label(
        "Z: ----.-- uT",
        x=10,
        y=180,
        text_c=0x5DADE2,
        bg_c=0x111820,
        bg_opa=0,
        font=lv.font_montserrat_14,
        parent=page0,
    )
    label_temperature = m5ui.M5Label(
        "Temp: --.- degC",
        x=10,
        y=205,
        text_c=0xE8EDF2,
        bg_c=0x111820,
        bg_opa=0,
        font=lv.font_montserrat_14,
        parent=page0,
    )
    button_calibrate = m5ui.M5Button(
        text="Calibrate",
        x=180,
        y=173,
        bg_c=0x147D73,
        text_c=0xFFFFFF,
        font=lv.font_montserrat_14,
        parent=page0,
    )

    button_calibrate.add_event_cb(button_calibrate_event_handler, lv.EVENT.ALL, None)

    i2c0 = I2C(0, scl=Pin(1), sda=Pin(2), freq=400000)
    bmm350_0 = BMM350Unit(i2c0)
    page0.screen_load()


def loop():
    global \
        page0, \
        label_title, \
        label_status, \
        label_heading, \
        label_x, \
        label_y, \
        label_z, \
        label_temperature, \
        button_calibrate, \
        i2c0, \
        bmm350_0, \
        magnetic, \
        calibration_result, \
        temperature, \
        heading, \
        mag_x, \
        mag_y, \
        mag_z
    M5.update()
    magnetic = bmm350_0.get_mag()
    temperature = bmm350_0.get_temperature()
    heading = bmm350_0.get_heading()
    mag_x = magnetic[0]
    mag_y = magnetic[1]
    mag_z = magnetic[2]
    label_heading.set_text(str((str("Heading: ") + str((int(heading))))))
    label_x.set_text(str((str("X: ") + str((str(mag_x) + str(" uT"))))))
    label_y.set_text(str((str("Y: ") + str((str(mag_y) + str(" uT"))))))
    label_z.set_text(str((str("Z: ") + str((str(mag_z) + str(" uT"))))))
    label_temperature.set_text(
        str((str("Temp: ") + str((str((int(temperature))) + str(" degC")))))
    )
    time.sleep_ms(50)


if __name__ == "__main__":
    try:
        setup()
        while True:
            loop()
    except (Exception, KeyboardInterrupt) as e:
        try:
            m5ui.deinit()
            from utility import print_error_msg

            print_error_msg(e)
        except ImportError:
            print("please update to latest firmware")