疫情影响，只能在家歇着。突然发现几个月前购买的一个oled显示屏，我试试把显示屏驱动起来看看。
led显示屏是1.3寸的单色oled，驱动新品是ssd1306；接口是i2C；我的单片机是nodemcu，芯片esp8266.
1、接线正确
模块一共4线
1、VCC 电源 3.3V
2、GND 地线
3、scl i2c 时钟
4、sda i2c 数据
nodemcu连接采用d1和d2，也就是8266的pin（5）和pin（4）：即scl=Pin(5), sda=Pin(4)。
2、驱动程序
根据淘宝供货商的驱动，下载后发现是c程序。我觉得用micropython比较方便，于是直接使用micropython里面的ssd1306驱动，发现该驱动部分可以使用，比如开关电源可以使用，画英文也可以使用，但是有很多雪花状的点，证明该驱动有问题，不适用。后来查程序，发现淘宝供应商提供的程序也是存在一样问题。通过查找其他人（https://blog.csdn.net/zhufu86/article/details/119246782）对问题处理的博客，需要修改两个寄存器。
3、测试程序如下：
from machine import Pin, I2C
import ssd1307
import time
i2c = I2C(scl=Pin(5), sda=Pin(4), freq=100000)
display = ssd1307.SSD1306_I2C(128, 64, i2c)
for i in range(40):
display.fill(0)
display.text("my clock",0,0,1)
display.text("now:"+str(i),0,20,1)
display.show()
time.sleep(1) # sleep for 1 second
display.fill(0)
display.text("over!!",30,25,1)
display.show()
效果如下：
3、驱动程序修改如下：
我把文件名改为ssd1307.py
# MicroPython SSD1306 OLED driver, I2C and SPI interfaces
from micropython import const
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)
# Subclassing FrameBuffer provides support for graphics primitives
# http://docs.micropython.org/en/latest/pyboard/library/framebuf.html
class SSD1306(framebuf.FrameBuffer):
def __init__(self, width, height, external_vcc):
self.width = width
self.height = height
self.external_vcc = external_vcc
self.pages = self.height // 8
self.buffer = bytearray(self.pages * self.width)
super().__init__(self.buffer, self.width, self.height, framebuf.MONO_VLSB)
self.init_display()
def init_display(self):
for cmd in (
SET_DISP | 0x00, # off
# address setting
SET_MEM_ADDR, 0x02, # Page Addressing Mode
# 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 poweron(self):
self.write_cmd(SET_DISP | 0x01)
def contrast(self, contrast):
self.write_cmd(SET_CONTRAST)
self.write_cmd(contrast)
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
buffer_mv = memoryview(self.buffer)
for i in range(0,8):
self.write_cmd(0x02) # Lower 4-bit, Column Start Address = 0x02
self.write_cmd(0x10) # Higher 4-bit, Column Start Address = 0x02
self.write_cmd(0xb0 | i) # 设置页面地址
self.write_data(buffer_mv[i * 128 : i * 128 + 128]) # 发送一页的数据
class SSD1306_I2C(SSD1306):
def __init__(self, width, height, i2c, addr=0x3c, external_vcc=False):
self.i2c = i2c
self.addr = addr
self.temp = bytearray(2)
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_data(self, buf):
self.temp[0] = self.addr << 1
self.temp[1] = 0x40 # Co=0, D/C#=1
self.i2c.start()
self.i2c.write(self.temp)
self.i2c.write(buf)
self.i2c.stop()
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
import time
self.res(1)
time.sleep_ms(1)
self.res(0)
time.sleep_ms(10)
self.res(1)
super().__init__(width, height, external_vcc)
def write_cmd(self, cmd):
self.spi.init(baudrate=self.rate, polarity=0, phase=0)
self.cs(1)
self.dc(0)
self.cs(0)
self.spi.write(bytearray([cmd]))
self.cs(1)
def write_data(self, buf):
self.spi.init(baudrate=self.rate, polarity=0, phase=0)
self.cs(1)
self.dc(1)
self.cs(0)
self.spi.write(buf)
self.cs(1)
