Micropython——使用I2C通信的OLED显示屏

文章目录

I2C通信OLED屏接线SSD1306库I2C使用方法查找OLEDI2C地址主函数代码显示动态数值效果展示

I2C通信

I2C通信是一种单片机常用的通信协议，它具有一根总线设计，具有一个主机，可以挂载多个设备在总线上作为从机，主机通过选定不同的发送地址来发送内容给不同的从机。

OLED屏

采用具有4针脚的，支持I2C通信的OLED屏，大小为0.96寸的单色小屏，像素数为128x64。

接线

使用X9、X10引脚

PYBOLEDVCC3.3VGNDGNDX9SCLX10SDA

SSD1306库

ssd1306.py

# MicroPython SSD1306 OLED driver, I2C and SPI interfaces import time import framebuf # register definitions SET_CONTRAST = const(0x81) SET_ENTIRE_ON = const(0xa4) SET_NORM_INV = const(0xa6) SET_DISP = const(0xae) SET_MEM_ADDR = const(0x20) SET_COL_ADDR = const(0x21) SET_PAGE_ADDR = const(0x22) SET_DISP_START_LINE = const(0x40) SET_SEG_REMAP = const(0xa0) SET_MUX_RATIO = const(0xa8) SET_COM_OUT_DIR = const(0xc0) SET_DISP_OFFSET = const(0xd3) SET_COM_PIN_CFG = const(0xda) SET_DISP_CLK_DIV = const(0xd5) SET_PRECHARGE = const(0xd9) SET_VCOM_DESEL = const(0xdb) SET_CHARGE_PUMP = const(0x8d) class SSD1306: def __init__(self, width, height, external_vcc): self.width = width self.height = height self.external_vcc = external_vcc self.pages = self.height // 8 # Note the subclass must initialize self.framebuf to a framebuffer. # This is necessary because the underlying data buffer is different # between I2C and SPI implementations (I2C needs an extra byte). self.poweron() self.init_display() def init_display(self): for cmd in ( SET_DISP | 0x00, # off # address setting SET_MEM_ADDR, 0x00, # horizontal # resolution and layout SET_DISP_START_LINE | 0x00, SET_SEG_REMAP | 0x01, # column addr 127 mapped to SEG0 SET_MUX_RATIO, self.height - 1, SET_COM_OUT_DIR | 0x08, # scan from COM[N] to COM0 SET_DISP_OFFSET, 0x00, SET_COM_PIN_CFG, 0x02 if self.height == 32 else 0x12, # timing and driving scheme SET_DISP_CLK_DIV, 0x80, SET_PRECHARGE, 0x22 if self.external_vcc else 0xf1, SET_VCOM_DESEL, 0x30, # 0.83*Vcc # display SET_CONTRAST, 0xff, # maximum SET_ENTIRE_ON, # output follows RAM contents SET_NORM_INV, # not inverted # charge pump SET_CHARGE_PUMP, 0x10 if self.external_vcc else 0x14, SET_DISP | 0x01): # on self.write_cmd(cmd) self.fill(0) self.show() def poweroff(self): self.write_cmd(SET_DISP | 0x00) def contrast(self, contrast): self.write_cmd(SET_CONTRAST) self.write_cmd(contrast) #翻转颜色 def invert(self, invert): self.write_cmd(SET_NORM_INV | (invert & 1)) def show(self): x0 = 0 x1 = self.width - 1 if self.width == 64: # displays with width of 64 pixels are shifted by 32 x0 += 32 x1 += 32 self.write_cmd(SET_COL_ADDR) self.write_cmd(x0) self.write_cmd(x1) self.write_cmd(SET_PAGE_ADDR) self.write_cmd(0) self.write_cmd(self.pages - 1) self.write_framebuf() #填充画面 0为空 1为亮 def fill(self, col): self.framebuf.fill(col) #填充一个像素在X,YE def pixel(self, x, y, col): self.framebuf.pixel(x, y, col) #滚动 def scroll(self, dx, dy): self.framebuf.scroll(dx, dy) #文本 def text(self, string, x, y, col=1): self.framebuf.text(string, x, y, col) def hline(self, x, y, w, col=1): self.framebuf.hline(x, y, w, col) class SSD1306_I2C(SSD1306): def __init__(self, width, height, i2c, addr=60, external_vcc=False): self.i2c = i2c self.addr = addr self.temp = bytearray(2) # Add an extra byte to the data buffer to hold an I2C data/command byte # to use hardware-compatible I2C transactions. A memoryview of the # buffer is used to mask this byte from the framebuffer operations # (without a major memory hit as memoryview doesn't copy to a separate # buffer). self.buffer = bytearray(((height // 8) * width) + 1) self.buffer[0] = 0x40 # Set first byte of data buffer to Co=0, D/C=1 self.framebuf = framebuf.FrameBuffer1(memoryview(self.buffer)[1:], width, height) super().__init__(width, height, external_vcc) def write_cmd(self, cmd): self.temp[0] = 0x80 # Co=1, D/C#=0 self.temp[1] = cmd self.i2c.writeto(self.addr, self.temp) def write_framebuf(self): # Blast out the frame buffer using a single I2C transaction to support # hardware I2C interfaces. self.i2c.writeto(self.addr, self.buffer) def poweron(self): pass class SSD1306_SPI(SSD1306): def __init__(self, width, height, spi, dc, res, cs, external_vcc=False): self.rate = 10 * 1024 * 1024 dc.init(dc.OUT, value=0) res.init(res.OUT, value=0) cs.init(cs.OUT, value=1) self.spi = spi self.dc = dc self.res = res self.cs = cs self.buffer = bytearray((height // 8) * width) self.framebuf = framebuf.FrameBuffer1(self.buffer, width, height) super().__init__(width, height, external_vcc) def write_cmd(self, cmd): self.spi.init(baudrate=self.rate, polarity=0, phase=0) self.cs.high() self.dc.low() self.cs.low() self.spi.write(bytearray([cmd])) self.cs.high() def write_framebuf(self): self.spi.init(baudrate=self.rate, polarity=0, phase=0) self.cs.high() self.dc.high() self.cs.low() self.spi.write(self.buffer) self.cs.high() def poweron(self): self.res.high() time.sleep_ms(1) self.res.low() time.sleep_ms(10) self.res.high()

I2C使用方法

I2C类 – 二线串行协议

查找OLEDI2C地址

在使用前，需要在putty中查找OLED的地址，并在ssd1306.py的SSD1306_I2C类中对addr进行特定的修改才能正常使用。

from pyb import I2C i2c = I2C(2) # create on bus 2 i2c.init(I2C.MASTER, baudrate=20000) i2c.scan()

返回的列表中的地址即为OLED的地址，将ssd1306.py的SSD1306_I2C类中对addr更改为你返回的地址即可，我这里是60。

主函数代码

from machine import I2C,Pin from ssd1306 import SSD1306_I2C if __name__ == "__main__": i2c = I2C(scl = Pin("X9"),sda = Pin("X10"),freq = 10000) #软件I2C oled = SSD1306_I2C(128, 64, i2c) #创建oled对象 oled.text("Hello World!",0,0) oled.text("i love u!",20,40) oled.show()

显示动态数值

from machine import I2C,Pin from ssd1306 import SSD1306_I2C def mainTimer_cb(cb): ''' #函数功能：用于总体程序的逻辑定时功能 ''' global count LED(3).toggle() count += 1 print(count) if __name__ == "__main__": count = 0 mainTimer = Timer(1, freq=2, callback=mainTimer_cb) # 主程序逻辑控制定时器 i2c = I2C(scl = Pin("X9"),sda = Pin("X10"),freq = 10000) #软件I2C oled = SSD1306_I2C(128, 64, i2c) #创建oled对象 oled.text("Hello World!",0,0) oled.text("i love u!",20,40) oled.show() while True: if (count%8) == 0: # LED(2).toggle() elif (count%20) == 0: count = 0 if (count%5) == 0: text = str(count) oled.fill(0) text = str(count) oled.text(text,50,0) oled.show()

需要注意的是： OLED的所有子函数均不能在定时器中刷新，否则会报错Memory Error！

效果展示