用micpython写一个ILI9342C驱动程序

ILI9342C是一款常见的TFT LCD控制器芯片，它可以通过SPI接口与微控制器通信。以下是一个基本的Micropython ILI9342C驱动程序的示例：

from micropython import const
import framebuf
import time

# ILI9342C命令
ILI_NOP = const(0x00)
ILI_SWRESET = const(0x01)
ILI_RDDID = const(0x04)
ILI_RDDST = const(0x09)

# 控制寄存器
ILI_SLPIN = const(0x10)
ILI_SLPOUT = const(0x11)
ILI_PTLON = const(0x12)
ILI_NORON = const(0x13)

# 显示窗口
ILI_CASET = const(0x2A)
ILI_PASET = const(0x2B)
ILI_RAMWR = const(0x2C)

# 颜色格式
ILI_COLMOD = const(0x3A)

class ILI9342C(framebuf.FrameBuffer):
    def __init__(self, spi, cs, dc, rst=None, width=240, height=320):
        self.spi = spi
        self.cs = cs
        self.dc = dc
        self.rst = rst
        self.width = width
        self.height = height
        self.buffer = bytearray(width * height * 2)
        super().__init__(self.buffer, width, height, framebuf.RGB565)

        self.reset()
        self.init()

    def reset(self):
        if self.rst != None:
            self.rst.value(0)
            time.sleep_ms(50)
            self.rst.value(1)
            time.sleep_ms(50)

    def init(self):
        # 初始化步骤1
        self.write_cmd(ILI_SWRESET)
        time.sleep_ms(120)

        # 初始化步骤2
        self.write_cmd(0xEF)
        self.write_data(0x03)
        self.write_data(0x80)
        self.write_data(0x02)

        # 初始化步骤3
        self.write_cmd(0xCF)
        self.write_data(0x00)
        self.write_data(0xC1)
        self.write_data(0x30)

        # 初始化步骤4
        self.write_cmd(0xED)
        self.write_data(0x64)
        self.write_data(0x03)
        self.write_data(0x12)
        self.write_data(0x81)

        # 初始化步骤5
        self.write_cmd(0xE8)
        self.write_data(0x85)
        self.write_data(0x00)
        self.write_data(0x78)

        # 初始化步骤6
        self.write_cmd(0xCB)
        self.write_data(0x39)
        self.write_data(0x2C)
        self.write_data(0x00)
        self.write_data(0x34)
        self.write_data(0x02)

        # 初始化步骤7
        self.write_cmd(0xF7)
        self.write_data(0x20)

        # 初始化步骤8
        self.write_cmd(0xEA)
        self.write_data(0x00)
        self.write_data(0x00)

        # 初始化步骤9
        self.write_cmd(ILI_COLMOD)
        self.write_data(0x55)

        # 初始化步骤10
        self.write_cmd(ILI_MADCTL)
        self.write_data(0x48)

        # 初始化步骤11
        self.write_cmd(ILI_SLPOUT)
        time.sleep_ms(120)

        # 初始化步骤12
        self.write_cmd(ILI_DISPON)

    def write_cmd(self, cmd):
        self.dc.value(0) # 发送命令
        self.cs.value(0) # 选中芯片
        self.spi.write(bytearray([cmd]))
        self.cs.value(1) # 取消片选

    def write_data(self, data):
        self.dc.value(1) # 发送数据
        self.cs.value(0) # 选中芯片
        self.spi.write(bytearray([data]))
        self.cs.value(1) # 取消片选

    def show(self):
        self.write_cmd(ILI_CASET)
        self.write_data(0)
        self.write_data(0)
        self.write_data(self.width >> 8)
        self.write_data(self.width & 0xFF)

        self.write_cmd(ILI_PASET)
        self.write_data(0)
        self.write_data(0)
        self.write_data(self.height >> 8)
        self.write_data(self.height & 0xFF)

        self.write_cmd(ILI_RAMWR)
        self.cs.value(1)
        self.dc.value(1)
        self.cs.value(0)
        self.spi.write(self.buffer)
        self.cs.value(1)

使用此驱动程序，您可以像下面这样在Micropython中初始化并使用ILI9342C：

import machine
import ili9342c

spi = machine.SPI(1, baudrate=20000000, polarity=0, phase=0)
cs = machine.Pin(15, machine.Pin.OUT)
dc = machine.Pin(2, machine.Pin.OUT)
rst = machine.Pin(0, machine.Pin.OUT)

display = ili9342c.ILI9342C(spi, cs, dc, rst)
display.fill(0xFFFF)
display.show()

在上面的示例中，我们使用SPI1接口，SCLK、MOSI和MISO分别连接到IO14、IO13和IO12引脚。片选引脚连接到IO15，数据/命令（DC）引脚连接到IO2，复位（RST）引脚连接到IO0。连接后，我们可以使用`fill()`填充显示器并使用`show()`显示图像。