【得捷电子Follow me第1期】任务2：驱动外设

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【得捷电子Follow me第1期】任务2：驱动外设 [复制链接]

# 1 驱动OLED

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## 1.1 技术参数

| Parameter| Value|
| :------------: | :------------: |
| Input voltage |3.3V / 5V |
| Output voltage| 0 ~ 2.3V|
| Pixels| 128 x 64|
| Temperature Range| -40℃ ~ +85 ℃|

##  1.2 ssd1306.py库文件

### 1.2.1 下载sd1306.py库文件

https://github.com/jdhxyy/ssd1306py-micropython/blob/master/ssd1306py/ssd1306.py

```python
#MicroPython SSD1306 OLED driver, I2C and SPI interfaces created by Adafruit

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)

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()

def fill(self, col):
  self.framebuf.fill(col)

def pixel(self, x, y, col):
  self.framebuf.pixel(x, y, col)

def scroll(self, dx, dy):
  self.framebuf.scroll(dx, dy)

def text(self, string, x, y, col=1):
  self.framebuf.text(string, x, y, col)

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)
  # 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()
```
### 1.2.2 编写OLED测试程序

```python
#【得捷电子Follow me第1期】任务2：驱动外设(1)OLED
from machine import Pin, I2C
from ssd1306 import SSD1306_I2C
import time
i2c = I2C(0,sda=Pin(8), scl=Pin(9))
oled = SSD1306_I2C(128, 64, i2c)
oled.fill(0)
oled.text('Hello World!', 0, 0)
oled.show()
```

# 2 驱动蜂鸣器

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## 2.1 编写程序

```python
#【得捷电子Follow me第1期】任务2：驱动外设(2)无源蜂鸣器警笛
from machine import Pin, I2C, PWM
from ssd1306 import SSD1306_I2C
import time
i2c = I2C(0,sda=Pin(8), scl=Pin(9))
oled = SSD1306_I2C(128, 64, i2c)
buzzer = PWM(machine.Pin(20))
oled.fill(0)
oled.text('Fire', 0, 0)
oled.show()
while True:
  for freq in range(500,1000,5):
  buzzer.freq(freq)
  time.sleep(0.002)
  for freq in range(1000,500,-5):
  buzzer.freq(freq)
  time.sleep(0.002)
```

火辣西米秀

驱动OLED看来不太复杂

OLED测试程序的代码看来是简单

【得捷电子Follow me第1期】任务2：驱动外设 [复制链接]

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