1.4. MicroPython 在 ESP32 上

MicroPython 是 Python 3 的精简实现，可在微控制器上运行。

1.4.1. 固件烧录

# 安装 esptool
pip install esptool

# 擦除 Flash
esptool.py --chip esp32 --port COM3 erase_flash

# 烧录 MicroPython 固件
# 下载固件: https://micropython.org/download/ESP32_GENERIC/
esptool.py --chip esp32 --port COM3 \
    write_flash -z 0x1000 esp32-20231005-v1.21.0.bin

# 验证
esptool.py --chip esp32 --port COM3 verify_flash \
    0x1000 esp32-20231005-v1.21.0.bin

1.4.2. REPL 交互

# 使用串口连接 (115200 baud)
# Windows: PuTTY / MobaXterm
#          也可用: picocom / screen

picocom /dev/ttyUSB0 -b 115200    # Linux
screen /dev/ttyUSB0 115200         # macOS

>>> print("Hello ESP32!")
Hello ESP32!

>>> import machine
>>> machine.freq()
240000000

>>> import esp
>>> esp.flash_size()
4194304

1.4.3. 基本示例

1.4.3.1. LED 闪烁

from machine import Pin
import time

led = Pin(2, Pin.OUT)

while True:
    led.on()
    time.sleep(0.5)
    led.off()
    time.sleep(0.5)

1.4.3.2. 按键输入

from machine import Pin

button = Pin(0, Pin.IN, Pin.PULL_UP)
led = Pin(2, Pin.OUT)

while True:
    if button.value() == 0:    # 按下（低电平）
        led.on()
    else:
        led.off()

1.4.3.3. PWM 呼吸灯

from machine import Pin, PWM
import time

pwm = PWM(Pin(2), freq=1000)

duty = 0
direction = 1

while True:
    duty += direction * 10
    if duty >= 1023:
        direction = -1
    elif duty <= 0:
        direction = 1
    pwm.duty(duty)
    time.sleep_ms(5)

1.4.3.4. ADC 读取

from machine import ADC, Pin
import time

adc = ADC(Pin(34))          # ADC1 通道
adc.atten(ADC.ATTN_11DB)     # 0~3.3V

while True:
    raw = adc.read()         # 0~4095
    voltage = raw / 4095 * 3.3
    print(f"ADC: {raw}, {voltage:.2f}V")
    time.sleep_ms(500)

1.4.4. I2C 总线

from machine import I2C, Pin
import time

# 初始化 I2C (ESP32 默认: SCL=22, SDA=21)
i2c = I2C(0, scl=Pin(22), sda=Pin(21), freq=400000)

# 扫描设备
devices = i2c.scan()
print(f"I2C 设备: {[hex(d) for d in devices]}")

# 读写 (以 MPU6050 为例)
i2c.writeto(0x68, bytearray([0x6B, 0x00]))  # 唤醒
data = i2c.readfrom_mem(0x68, 0x3B, 14)     # 读传感器数据

1.4.5. WiFi 连接

import network
import time

def wifi_connect(ssid, password):
    wlan = network.WLAN(network.STA_IF)
    wlan.active(True)

    if not wlan.isconnected():
        print(f"连接 {ssid}...")
        wlan.connect(ssid, password)

        timeout = 30
        while not wlan.isconnected() and timeout > 0:
            time.sleep(1)
            timeout -= 1

    if wlan.isconnected():
        print(f"已连接, IP: {wlan.ifconfig()[0]}")
    else:
        print("连接失败")

wifi_connect("MyWiFi", "password123")

1.4.5.1. Web 服务器

import socket

def web_server():
    addr = socket.getaddrinfo('0.0.0.0', 80)[0][-1]
    s = socket.socket()
    s.bind(addr)
    s.listen(5)
    print(f"Web 服务器启动: {addr}")

    while True:
        conn, addr = s.accept()
        print(f"客户端连接: {addr}")

        request = conn.recv(1024)
        html = """<!DOCTYPE html>
        <html><head><title>ESP32</title></head><body>
        <h1>Hello from ESP32 MicroPython!</h1>
        </body></html>"""

        conn.send('HTTP/1.1 200 OK\n')
        conn.send('Content-Type: text/html\n')
        conn.send('Connection: close\n\n')
        conn.sendall(html)
        conn.close()

1.4.6. 文件管理

# 上传文件到 ESP32
# 使用 ampy / rshell / Thonny

# ampy (Adafruit MicroPython Tool)
pip install adafruit-ampy
ampy --port COM3 put main.py
ampy --port COM3 ls /
ampy --port COM3 get boot.py

# 在 REPL 中管理文件
import os

os.listdir('/')          # 列出文件
os.mkdir('/lib')         # 创建目录
os.remove('test.py')     # 删除文件
os.stat('main.py')       # 文件信息

小技巧

MicroPython 在 ESP32 上的限制：

• 内存有限：约 100 KB 可用堆空间

• 浮点运算较慢（软件模拟）

• 不支持所有 ESP-IDF 功能（如 BLE Mesh）

• 适用于原型验证，量产建议使用 ESP-IDF