一、目的

        这一节我们来学习如何使用ESP32连接AHT20温湿度模块和ST7735s屏幕，来显示温湿度。

二、环境

        ESP32开发板（MicroPython v1.19.1 on 2022-06-18）+ AHT20温湿度传感器模块+ st7735s显示屏 + Win10商业

        ESP32和AHT20温湿度模块接线方法：

        ESP32和st7735s屏幕接线方法：

 三、示例代码1

温湿度竖屏显示.py

from machine import Pin,SPI,I2C,PWM
from st7735s import ST7735,color
from ufont import BMFont
from ahtx0 import AHT20

import time

spi = SPI(2,baudrate=80_000_000,polarity = 0,sck = Pin(18),mosi = Pin(23))
tft = ST7735(spi,rst=4, dc=2, cs=5,bl=19,width=128,height=160, rotate=0)
i2c = I2C(1,scl = Pin(25),sda = Pin(26),freq = 400_000) # 默认I2C1是25和26Pin
aht = AHT20(i2c)

font = BMFont("font.bmf")

def ahtxx():
    
    temp = aht.temperature
    humi = aht.relative_humidity

    font.text(tft,"温度= %.2f ℃"%(temp),10,36,color(255,255,255),font_size=16,reverse=False,clear=False,show=True,auto_wrap=True)
    font.text(tft,"湿度= %.2f %s" %(humi,'%'),10,56,color(255,255,255),font_size=16,reverse=False,clear=False,show=True,auto_wrap=True)
    
    time.sleep(0.1)
    
def main():
    tft.init()
    #tft.fill(color(0,0,0))
    #tft.show()
    font.text(tft,"温湿度",36,0,color(0,255,0),font_size=16,reverse=False,clear=True,show=True,auto_wrap=True)
    tft.hline(0,25,160,color(255,255,255))
    tft.show()
    
    #font.text(tft,"%#x"%i2c.scan()[0],0,50,color(0,255,0),font_size=32,reverse=False,clear=False,show=True,auto_wrap=True)
    
    while True:
        ahtxx()
    
if __name__ == "__main__":
    main()

显示效果：

 

四、示例代码2

温湿度横屏显示.py

from machine import Pin,SPI,I2C,PWM
from st7735s import ST7735,color
from ufont import BMFont
from ahtx0 import AHT20

import time

spi = SPI(2,baudrate=80_000_000,polarity = 0,sck = Pin(18),mosi = Pin(23))
tft = ST7735(spi,rst=4, dc=2, cs=5,bl=19,width=160,height=128, rotate=1)
i2c = I2C(1,scl = Pin(25),sda = Pin(26),freq = 400_000) # 默认I2C1是25和26Pin
aht = AHT20(i2c)

font = BMFont("font.bmf")

def ahtxx():
    
    temp = aht.temperature
    humi = aht.relative_humidity

    font.text(tft,"温度= %.2f ℃"%(temp),10,36,color(255,255,255),font_size=16,reverse=False,clear=False,show=True,auto_wrap=True)
    font.text(tft,"湿度= %.2f %s" %(humi,'%'),10,56,color(255,255,255),font_size=16,reverse=False,clear=False,show=True,auto_wrap=True)
    
    time.sleep(0.1)
    
def main():
    tft.init()
    #tft.fill(color(0,0,0))
    #tft.show()
    font.text(tft,"温湿度",36,0,color(0,255,0),font_size=16,reverse=False,clear=True,show=True,auto_wrap=True)
    tft.hline(0,25,160,color(255,255,255))
    tft.show()
    
    #font.text(tft,"%#x"%i2c.scan()[0],0,50,color(0,255,0),font_size=32,reverse=False,clear=False,show=True,auto_wrap=True)
    
    while True:
        ahtxx()
    
if __name__ == "__main__":
    main()

显示效果：

五、st7735s屏幕驱动

st7735s.py

"""
合宙 Air10x 系列屏幕扩展板驱动
160(H)RGB x 80(V)

使用方法(以合宙ESP32C3为例):
    from machine import SPI, Pin
    from st7735 import ST7735

    spi = SPI(1, 30000000, sck=Pin(2), mosi=Pin(3))
    ST7735(spi, rst=10, dc=6, cs=7, bl=11, width=160, height=80, rotate=1)  # 直插横屏显示
    ST7735(spi, rst=10, dc=6, cs=7, bl=11, width=160, height=80, rotate=0)  # 直插竖屏显示

本款LCD使用的内置控制器为ST7735S，是一款162 x RGB x 132像素的LCD控制器,而本LCD本身的像素为160(H)RGB x 80(V)。由于LCD的显示
起始位置与控制器的原点不一致，因此在使用控制器初始化显示全屏显示区域时需要对做偏移处理：水平方向从第二个像素点开始显示，垂直方向从第27个像素点
开始。这样就可以保证显示的LCD中RAM对应的位置与实际一致。(https://www.waveshare.net/wiki/Pico-LCD-0.96)

屏幕详细信息: https://wiki.luatos.com/peripherals/lcd_air10x/index.html
ST7735S文档: https://www.waveshare.net/w/upload/e/e2/ST7735S_V1.1_20111121.pdf
FrameBuf文档: https://docs.micropython.org/en/latest/library/framebuf.html
"""
import gc
import time
import math

import machine
import framebuf
from micropython import const

SWRESET = const(0x01)
SLPOUT = const(0x11)
NORON = const(0x13)

INVOFF = const(0x20)
DISPON = const(0x29)
CASET = const(0x2A)
RASET = const(0x2B)
RAMWR = const(0x2C)

MADCTL = const(0x36)
COLMOD = const(0x3A)

FRMCTR1 = const(0xB1)
FRMCTR2 = const(0xB2)
FRMCTR3 = const(0xB3)

INVCTR = const(0xB4)

PWCTR1 = const(0xC0)
PWCTR2 = const(0xC1)
PWCTR3 = const(0xC2)
PWCTR4 = const(0xC3)
PWCTR5 = const(0xC4)
VMCTR1 = const(0xC5)

GMCTRP1 = const(0xE0)
GMCTRN1 = const(0xE1)

ROTATIONS = [0x00, 0x60]  # 只给了两个旋转方向


def color(r, g, b):
    i = (((b & 0xF8) << 8) | ((g & 0xFC) << 3) | (r >> 3)).to_bytes(2, "little")
    return (i[0] << 8) + i[1]


RED = color(255, 0, 0)
GREEN = color(0, 255, 0)
BLUE = color(0, 0, 255)
WHITE = color(255, 255, 255)
BLACK = color(0, 0, 0)


class ST7735(framebuf.FrameBuffer):
    def __init__(self, spi, rst, dc, cs, bl=None, width=80, height=160, offset=None, rotate=1, rgb=True):
        """
        :param spi:
        :param rst:
        :param dc:
        :param cs: 使能
        :param bl: 背光
        :param width: 宽度
        :param height: 高度
        :param offset: 偏移 (x, y): (23, -1)|(-1, 23)
        :param rotate: 旋转 0 横屏 1 竖屏
        :param rgb: RGB 色彩模式
        """
        # 根据方向自动设置偏移
        self.rotate = rotate
        self.offset = offset
        self.rgb = rgb
        if offset is None and rotate == 1:
            self.offset = (-1, -1)  #原值为self.offset = (-1, 23) # 横屏显示
        elif offset is None and rotate == 0:
            self.offset = (-1, -1)  #原值为self.offset = (23, -1) # 竖屏显示
        self.width = width
        self.height = height

        self.spi = spi
        self.rst = machine.Pin(rst, machine.Pin.OUT, machine.Pin.PULL_DOWN)
        self.dc = machine.Pin(dc, machine.Pin.OUT, machine.Pin.PULL_DOWN)
        self.cs = machine.Pin(cs, machine.Pin.OUT, machine.Pin.PULL_DOWN)
        if bl is not None:
            self.bl = machine.PWM(machine.Pin(bl))

        gc.collect()
        self.buffer = bytearray(self.height * self.width * 2)
        super().__init__(self.buffer, self.width, self.height, framebuf.RGB565)
        self.init()
        self.set_windows()
        self.clear()

    def set_windows(self, x_start=None, y_start=None, x_end=None, y_end=None):
        """
        设置窗口
        :return:
        """
        x_start = (x_start + self.offset[0] + 1) if x_start is not None else (self.offset[0] + 1)
        x_end = x_end + self.rotate + self.offset[0] if x_end is not None else self.width + self.rotate + \
                                                                               self.offset[0]
        y_start = y_start + self.offset[1] + 1 if y_start is not None else self.offset[1] + 1
        y_end = y_end + self.rotate + self.offset[1] if y_end is not None else self.height + self.rotate + \
                                                                               self.offset[1]

        self.write_cmd(CASET)
        self.write_data(bytearray([0x00, x_start, 0x00, x_end]))

        self.write_cmd(RASET)
        self.write_data(bytearray([0x00, y_start, 0x00, y_end]))

        self.write_cmd(RAMWR)

    def init(self):
        self.reset()

        self.write_cmd(SWRESET)
        time.sleep_us(150)
        self.write_cmd(SLPOUT)
        time.sleep_us(300)

        self.write_cmd(FRMCTR1)
        self.write_data(bytearray([0x01, 0x2C, 0x2D]))
        self.write_cmd(FRMCTR2)
        self.write_data(bytearray([0x01, 0x2C, 0x2D]))
        self.write_cmd(FRMCTR3)
        self.write_data(bytearray([0x01, 0x2C, 0x2D, 0x01, 0x2C, 0x2D]))
        time.sleep_us(10)

        self.write_cmd(INVCTR)
        self.write_data(bytearray([0x07]))

        self.write_cmd(PWCTR1)
        self.write_data(bytearray([0xA2, 0x02, 0x84]))
        self.write_cmd(PWCTR2)
        self.write_data(bytearray([0xC5]))
        self.write_cmd(PWCTR3)
        self.write_data(bytearray([0x0A, 0x00]))
        self.write_cmd(PWCTR4)
        self.write_data(bytearray([0x8A, 0x2A]))
        self.write_cmd(PWCTR5)
        self.write_data(bytearray([0x8A, 0xEE]))
        self.write_cmd(VMCTR1)
        self.write_data(bytearray([0x0E]))

        self.write_cmd(INVOFF)

        self.write_cmd(MADCTL)
        self.write_data(bytearray([ROTATIONS[self.rotate] | 0x00 if self.rgb else 0x08]))

        self.write_cmd(COLMOD)
        self.write_data(bytearray([0x05]))

        self.write_cmd(GMCTRP1)
        self.write_data(
            bytearray([0x02, 0x1c, 0x07, 0x12, 0x37, 0x32, 0x29, 0x2d, 0x29, 0x25, 0x2b, 0x39, 0x00, 0x01, 0x03, 0x10]))

        self.write_cmd(GMCTRN1)
        self.write_data(
            bytearray([0x03, 0x1d, 0x07, 0x06, 0x2e, 0x2c, 0x29, 0x2d, 0x2e, 0x2e, 0x37, 0x3f, 0x00, 0x00, 0x02, 0x10]))

        self.write_cmd(NORON)
        time.sleep_us(10)

        self.write_cmd(DISPON)
        time.sleep_us(100)

        self.cs(1)

    def reset(self):
        """
        设备重置
        :return:
        """
        self.rst(1)
        time.sleep(0.2)
        self.rst(0)
        time.sleep(0.2)
        self.rst(1)
        time.sleep(0.2)

    def write_cmd(self, cmd):
        self.dc(0)
        self.cs(0)
        self.spi.write(bytearray([cmd]))
        self.cs(1)

    def write_data(self, buf):
        self.dc(1)
        self.cs(0)
        self.spi.write(buf)
        self.cs(1)

    def back_light(self, value):
        """
        背光调节
        :param value: 背光等级 0 ~ 256
        :return:
        """
        self.bl.freq(1000)
        if value >= 0xff:
            value = 0xff
        data = value * 0xffff >> 8
        self.bl.duty_u16(data)

    def clear(self):
        """
        清屏
        :return:
        """
        self.fill(0)
        self.show()

    def show(self):
        """
        显示
        :return:
        """
        self.set_windows()  # 如果没有这行就会偏移
        self.write_data(self.buffer)

    def circle(self, center, radius, c=color(255, 255, 255), section=100):
        """
        画圆
        :param c: 颜色
        :param center: 中心(x, y)
        :param radius: 半径
        :param section: 分段
        :return:
        """
        arr = []
        for m in range(section + 1):
            x = round(radius * math.cos((2 * math.pi / section) * m - math.pi) + center[0])
            y = round(radius * math.sin((2 * math.pi / section) * m - math.pi) + center[1])
            arr.append([x, y])
        for i in range(len(arr) - 1):
            self.line(*arr[i], *arr[i + 1], c)

    def image(self, file_name):
        with open(file_name, "rb") as bmp:
            for b in range(0, 80 * 160 * 2, 1024):
                self.buffer[b:b + 1024] = bmp.read(1024)
            self.show()

六、字体库

ufont.py

__version__ = 3

import time
import struct

import framebuf

DEBUG = False


def timeit(f, *args, **kwargs):
    try:
        myname = str(f).split(' ')[1]
    except:
        myname = "UNKONW"

    def new_func(*args, **kwargs):
        if DEBUG:
            try:
                t = time.ticks_us()
                result = f(*args, **kwargs)
                delta = time.ticks_diff(time.ticks_us(), t)
                print('Function {} Time = {:6.3f}ms'.format(myname, delta / 1000))
            except AttributeError:
                t = time.perf_counter_ns()
                result = f(*args, **kwargs)
                delta = time.perf_counter_ns() - t
                print('Function {} Time = {:6.3f}ms'.format(myname, delta / 1000000))
            return result
        else:
            return f(*args, **kwargs)

    return new_func


class BMFont:
    @staticmethod
    def _list_to_byte(arr):
        b = 0
        for a in arr:
            b = (b << 1) + a
        return bytes([b])

    @timeit
    def _bit_list_to_byte_data(self, bit_list):
        """将点阵转换为字节数据

        Args:
            bit_list:

        Returns:

        """
        byte_data = b''
        for _col in bit_list:
            for i in range(0, len(_col), 8):
                byte_data += self._list_to_byte(_col[i:i + 8])
        return byte_data

    @timeit
    def __init__(self, font_file):
        self.font_file = font_file

        self.font = open(font_file, "rb", buffering=0xff)

        self.bmf_info = self.font.read(16)

        if self.bmf_info[0:2] != b"BM":
            raise TypeError("字体文件格式不正确: " + font_file)

        self.version = self.bmf_info[2]
        if self.version != 3:
            raise TypeError("字体文件版本不正确: " + str(self.version))

        self.map_mode = self.bmf_info[3]  # 映射方式
        self.start_bitmap = struct.unpack(">I", b'\x00' + self.bmf_info[4:7])[0]  # 位图开始字节
        self.font_size = self.bmf_info[7]  # 字体大小
        self.bitmap_size = self.bmf_info[8]  # 点阵所占字节

    @timeit
    def _to_bit_list(self, byte_data, font_size, *, _height=None, _width=None):
        """将字节数据转换为点阵数据

        Args:
            byte_data: 字节数据
            font_size: 字号大小
            _height: 字体原高度
            _width: 字体原宽度

        Returns:

        """
        _height = _height or self.font_size
        _width = _width or self.bitmap_size // self.font_size * 8
        new_bitarray = [[0 for j in range(font_size)] for i in range(font_size)]
        for _col in range(len(new_bitarray)):
            for _row in range(len(new_bitarray[_col])):
                _index = int(_col / (font_size / _height)) * _width + int(_row / (font_size / _width))
                new_bitarray[_col][_row] = byte_data[_index // 8] >> (7 - _index % 8) & 1
        return new_bitarray

    @timeit
    def _color_render(self, bit_list, color):
        """将二值点阵图像转换为 RGB565 彩色字节图像

        Args:
            bit_list:
            color:

        Returns:

        """
        color_array = b""
        for _col in range(len(bit_list)):
            for _row in range(len(bit_list)):
                color_array += struct.pack("<H", color) if bit_list[_col][_row] else b'\x00\x00'
        return color_array

    @timeit
    def _get_index(self, word):
        """获取索引

        Args:
            word: 字符

        Returns:

        """
        word_code = ord(word)
        start = 0x10
        end = self.start_bitmap

        while start <= end:
            mid = ((start + end) // 4) * 2
            self.font.seek(mid, 0)
            target_code = struct.unpack(">H", self.font.read(2))[0]
            if word_code == target_code:
                return (mid - 16) >> 1
            elif word_code < target_code:
                end = mid - 2
            else:
                start = mid + 2
        return -1

    @timeit
    def get_bitmap(self, word):
        """获取点阵图

        Args:
            word: 字符

        Returns:
            bytes 字符点阵
        """
        index = self._get_index(word)
        if index == -1:
            return b'\xff\xff\xff\xff\xff\xff\xff\xff\xf0\x0f\xcf\xf3\xcf\xf3\xff\xf3\xff\xcf\xff?\xff?\xff\xff\xff' \
                   b'?\xff?\xff\xff\xff\xff'

        self.font.seek(self.start_bitmap + index * self.bitmap_size, 0)
        return self.font.read(self.bitmap_size)

    @timeit
    def text(self, display, string, x, y, color=1, *, font_size=None, reverse=False, clear=False, show=False,
             half_char=True, auto_wrap=False, **kwargs):
        """通过显示屏显示文字

        使用此函数显示文字，必须先确认显示对象是否继承与 framebuf.FrameBuffer。
        如果显示对象没有 clear 方法，需要自行调用 fill 清屏

        Args:
            display: 显示实例
            string: 字符串
            x: 字体左上角 x 轴
            y: 字体左上角 y 轴
            color: 颜色
            font_size: 字号
            reverse: 是否反转背景
            clear: 是否清除之前显示的内容
            show: 是否立刻显示
            half_char: 是否半字节显示 ASCII 字符
            auto_wrap: 自动换行
            **kwargs:

        Returns:
            None
        """
        font_size = font_size or self.font_size
        initial_x = x

        # 清屏
        try:
            display.clear() if clear else 0
        except AttributeError:
            print("请自行调用 display.fill(*) 清屏")

        for char in range(len(string)):
            # 是否自动换行
            if auto_wrap:
                if auto_wrap and ((x + font_size // 2 >= display.width and ord(string[char]) < 128 and half_char) or
                                  (x + font_size >= display.width and (not half_char or ord(string[char]) > 128))):
                    y += font_size
                    x = initial_x

            # 回车
            if string[char] == '\n':
                y += font_size
                x = initial_x
                continue
            # Tab
            elif string[char] == '\t':
                x = ((x // font_size) + 1) * font_size + initial_x % font_size
                continue
            # 其它的控制字符不显示
            elif ord(string[char]) < 16:
                continue

            # 超过范围的字符不会显示*
            if x > display.width or y > display.height:
                continue

            byte_data = list(self.get_bitmap(string[char]))

            # 反转
            if reverse:
                for _pixel in range(len(byte_data)):
                    byte_data[_pixel] = ~byte_data[_pixel] & 0xff

            # 缩放和色彩*
            if color > 1 or font_size != self.font_size:
                bit_data = self._to_bit_list(byte_data, font_size)
                if color > 1:
                    display.blit(
                        framebuf.FrameBuffer(bytearray(self._color_render(bit_data, color)), font_size, font_size,
                                             framebuf.RGB565), x, y)
                else:
                    display.blit(
                        framebuf.FrameBuffer(bytearray(self._bit_list_to_byte_data(bit_data)), font_size, font_size,
                                             framebuf.MONO_HLSB), x, y)
            else:
                display.blit(framebuf.FrameBuffer(bytearray(byte_data), font_size, font_size, framebuf.MONO_HLSB), x, y)

            # 英文字符半格显示
            if ord(string[char]) < 128 and half_char:
                x += font_size // 2
            else:
                x += font_size

        display.show() if show else 0

    def char(self, char, color=1, font_size=None, reverse=False):
        """ 获取字体字节数据

        在没有继承 framebuf.FrameBuffer 的显示驱动,或者内存不足以将一整个屏幕载入缓存帧时
        可以直接获取单字的字节数据,局部更新
        Args:
            char: 单个字符
            color: 颜色
            font_size: 字体大小
            reverse: 反转

        Returns:
            bytearray
        """
        font_size = font_size or self.font_size
        byte_data = list(self.get_bitmap(char))

        # 反转
        if reverse:
            for _pixel in range(len(byte_data)):
                byte_data[_pixel] = ~byte_data[_pixel] & 0xff
        if color > 1 or font_size != self.font_size:
            bit_data = self._to_bit_list(byte_data, font_size)
            if color > 1:
                return self._color_render(bit_data, color)
            else:
                return self._bit_list_to_byte_data(bit_data)
        else:
            return bytearray(byte_data)


if __name__ == '__main__':
    def show_bitmap(arr):
        """
        显示点阵字 MONO_HLSB
        :return:
        """
        for row in arr:
            for i in row:
                if i:
                    print('* ', end=' ')
                else:
                    print('. ', end=' ')
            print()


    font = BMFont("unifont-14-12888-16.v3.bmf")
    print("16 ----")
    bd = font.char("我", reverse=True, color=0xffff, font_size=16)
    print("24 ----")
    bd = font.char("我", reverse=True, color=0xffff, font_size=24)
    print("16 ----")
    # font._with_color(zoom(byte_to_bit(font.get_bitmap("我"), 16), 24), 0xff00)
    font._color_render(font._to_bit_list(font.get_bitmap("我"), 24), 0xff00)

七、AHT20温湿度模块驱动

ahtx0.py

# The MIT License (MIT)
#
# Copyright (c) 2020 Kattni Rembor for Adafruit Industries
# Copyright (c) 2020 Andreas Bühl
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
"""

MicroPython driver for the AHT10 and AHT20 Humidity and Temperature Sensor

Author(s): Andreas Bühl, Kattni Rembor

"""

import utime
from micropython import const


class AHT10:
    """Interface library for AHT10/AHT20 temperature+humidity sensors"""

    AHTX0_I2CADDR_DEFAULT = const(0x38)  # Default I2C address
    AHTX0_CMD_INITIALIZE = 0xE1  # Initialization command
    AHTX0_CMD_TRIGGER = const(0xAC)  # Trigger reading command
    AHTX0_CMD_SOFTRESET = const(0xBA)  # Soft reset command
    AHTX0_STATUS_BUSY = const(0x80)  # Status bit for busy
    AHTX0_STATUS_CALIBRATED = const(0x08)  # Status bit for calibrated

    def __init__(self, i2c, address=AHTX0_I2CADDR_DEFAULT):
        utime.sleep_ms(20)  # 20ms delay to wake up
        self._i2c = i2c
        self._address = address
        self._buf = bytearray(6)
        self.reset()
        if not self.initialize():
            raise RuntimeError("Could not initialize")
        self._temp = None
        self._humidity = None

    def reset(self):
        """Perform a soft-reset of the AHT"""
        self._buf[0] = self.AHTX0_CMD_SOFTRESET
        self._i2c.writeto(self._address, self._buf[0:1])
        utime.sleep_ms(20)  # 20ms delay to wake up

    def initialize(self):
        """Ask the sensor to self-initialize. Returns True on success, False otherwise"""
        self._buf[0] = self.AHTX0_CMD_INITIALIZE
        self._buf[1] = 0x08
        self._buf[2] = 0x00
        self._i2c.writeto(self._address, self._buf[0:3])
        self._wait_for_idle()
        if not self.status & self.AHTX0_STATUS_CALIBRATED:
            return False
        return True

    @property
    def status(self):
        """The status byte initially returned from the sensor, see datasheet for details"""
        self._read_to_buffer()
        return self._buf[0]

    @property
    def relative_humidity(self):
        """The measured relative humidity in percent."""
        self._perform_measurement()
        self._humidity = (
            (self._buf[1] << 12) | (self._buf[2] << 4) | (self._buf[3] >> 4)
        )
        self._humidity = (self._humidity * 100) / 0x100000
        return self._humidity

    @property
    def temperature(self):
        """The measured temperature in degrees Celcius."""
        self._perform_measurement()
        self._temp = ((self._buf[3] & 0xF) << 16) | (self._buf[4] << 8) | self._buf[5]
        self._temp = ((self._temp * 200.0) / 0x100000) - 50
        return self._temp

    def _read_to_buffer(self):
        """Read sensor data to buffer"""
        self._i2c.readfrom_into(self._address, self._buf)

    def _trigger_measurement(self):
        """Internal function for triggering the AHT to read temp/humidity"""
        self._buf[0] = self.AHTX0_CMD_TRIGGER
        self._buf[1] = 0x33
        self._buf[2] = 0x00
        self._i2c.writeto(self._address, self._buf[0:3])

    def _wait_for_idle(self):
        """Wait until sensor can receive a new command"""
        while self.status & self.AHTX0_STATUS_BUSY:
            utime.sleep_ms(5)

    def _perform_measurement(self):
        """Trigger measurement and write result to buffer"""
        self._trigger_measurement()
        self._wait_for_idle()
        self._read_to_buffer()


class AHT20(AHT10):
    AHTX0_CMD_INITIALIZE = 0xBE  # Calibration command

八、含有摄氏度符号的字库文件

font.bmp请从下方下载：

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大家也可以使用字库生成工具，制作自己需要的字体！

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2，st7735s屏幕

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