为什么在我的 Beaglebone Black 上运行此 i2c 示例代码时会出现 IOError？

Question

下面是Adafruit SSD1306 Library 中的 image.py 示例，用于在 BeagleBone Black 上通过 i2c 驱动 OLED 显示器。它给了我一个 IOError，但我对它的含义感到困惑。 IOError 可能是代码本身的问题，还是 BeagleBone 上的 i2c 配置问题？

import time

import Adafruit_GPIO.SPI as SPI
import Adafruit_SSD1306

import Image

# Beaglebone Black pin configuration:
RST = 'P9_12'
# Note the following are only used with SPI:
DC = 'P9_15'
SPI_PORT = 1
SPI_DEVICE = 0

# 128x32 display with hardware I2C:
#disp = Adafruit_SSD1306.SSD1306_128_32(rst=RST)

# 128x64 display with hardware I2C:
disp = Adafruit_SSD1306.SSD1306_128_64(rst=RST)

# 128x32 display with hardware SPI:
# disp = Adafruit_SSD1306.SSD1306_128_32(rst=RST, dc=DC, spi=SPI.SpiDev(SPI_PORT, SPI_DEVICE, max_speed_hz=8000000))

# 128x64 display with hardware SPI:
# disp = Adafruit_SSD1306.SSD1306_128_64(rst=RST, dc=DC, spi=SPI.SpiDev(SPI_PORT, SPI_DEVICE, max_speed_hz=8000000))

# Initialize library.
disp.begin()

# Clear display.
disp.clear()
disp.display()

# Load image based on OLED display height.  Note that image is converted to 1 bit color.
if disp.height == 64:
        image = Image.open('happycat_oled_64.ppm').convert('1')
else:
        image = Image.open('happycat_oled_32.ppm').convert('1')

# Alternatively load a different format image, resize it, and convert to 1 bit color.
#image = Image.open('happycat.png').resize((disp.width, disp.height), Image.ANTIALIAS).convert('1')

# Display image.
disp.image(image)
disp.display()

请看下面的跟踪：

/usr/local/lib/python2.7/dist-packages/setuptools-3.5.1-py2.7.egg/pkg_resources.py:1031: UserWarning: /home/ubuntu/.python-eggs is writable by group/others and vulnerable to attack when used with get_resource_filename. Consider a more secure location (set with .set_extraction_path or the PYTHON_EGG_CACHE environment variable).
Traceback (most recent call last):
  File "image.py", line 47, in <module>
    disp = Adafruit_SSD1306.SSD1306_128_64(rst=RST)
  File "build/bdist.linux-armv7l/egg/Adafruit_SSD1306/SSD1306.py", line 239, in __init__
  File "build/bdist.linux-armv7l/egg/Adafruit_SSD1306/SSD1306.py", line 105, in __init__
  File "build/bdist.linux-armv7l/egg/Adafruit_GPIO/I2C.py", line 64, in get_i2c_device
  File "build/bdist.linux-armv7l/egg/Adafruit_GPIO/I2C.py", line 75, in __init__
IOError: [Errno 2] No such file or directory

Answer 1

试试：

Image = Image.open('happycat_oled_64.ppm','r').convert('1')

或

Image = Image.open('happycat_oled_64.ppm','w').convert('1')