上一篇博客介绍了树莓派(raspberry)上使用spi接口的oled屏幕，今天就再把那个屏幕用到beaglebone black(BBB)上面，用它来使beaglebone black有个显示提示功能，可以用来调试等.屏幕还是那个：0.98寸的oled屏幕，ssd1306主控芯片,128*64的分辨率。
个人原创，版权所有，转载请注明原文出处，并保留原文链接：
http://www.embbnux.com/2014/08/10/beaglebone_black_use_spi_oled_ssd1306/
beaglebone和树莓派一样也有很多gpio口提供给用户，而且更多，资源也很丰富。
开始进入正题吧：
一 首先还是进行连线：
spi oled的接口和之前的一样:
连线:
GND >> Beaglebone black的P9_1管脚也就是GND
VCC >> Beaglebone black的P9_3即VDD_3V3
CS >> Beaglebone black的P9_17(SPI0_CS0)
DC >> Beaglebone black的 P9_15
RST >> Beaglebone black的 P9_12
D1(MOSI) >> Beaglebone black的SPI0_D1(P9_18)
D0(SCLK) >> Beaglebone black的SPI0_SCLK(P9_22)
二 在beaglebone black上开启spi接口
电脑用usb线连接上beaglebone black后，电脑上会多出一个磁盘分区：BEAGLEBONE，这个是beaglebone black上emmc上的一个分区，里面的文件就是beaglebone black的配置文件。
用文本编辑器打开uEnv.txt
在里面最后一行加入下面的语句：
optargs=capemgr.enable_partno=BB-SPIDEV0
重新启动beaglebone black后会在/dev目录下新增下面两个文件： spidev1.0 spidev1.１
对应的是beaglebone black的spi接口
这样就开启了
三 使用python操作oled准备
先是安装相应的库和程序：
我beaglebone black的系统目前是angstrom，如果是ubuntu的看再下面
angstrom：
使用ssh登陆到板子上：ssh [email protected]
/usr/bin/ntpdate -b -s -u pool.ntp.org opkg update opkg install task-native-sdk opkg install python-pip python-setuptools opkg install python-dev opkg install python-misc #不安装的话使用python提示找不到contextlib：No module named contextlib opkg install python-imaging python-smbus pip install Adafruit_BBIO opkg install git git clone https://github.com/adafruit/Adafruit_Python_SSD1306.git
git的时候出现了一下问题：
error: while accessing https://github.com/adafruit/Adafruit_Python_SSD1306.git/info/refs
fatal: HTTP request failed
原因是git上使用https需要验证，解决：
git config --global http.sslverify false git clone https://github.com/adafruit/Adafruit_Python_SSD1306.git
继续：
cd Adafruit_Python_SSD1306 python setup.py install
如果提示错误:
subprocess.CalledProcessError: Command ‘[‘curl’, ‘https://pypi.python.org/packages/source/s/setuptools/setuptools-3.5.1.zip’, ‘–silent’, ‘–output’, ‘/home/root/python/Adafruit_Python_SSD1306/setuptools-3.5.1.zip’]’ returned non-zero exit status 77
则下载https://pypi.python.org/packages/source/s/setuptools/setuptools-3.5.1.zip，放到Adafruit_Python_SSD1306目录下，再执行 python setup.py install
ubuntu的操作如下：
sudo apt-get update sudo apt-get install build-essential python-dev python-pip sudo pip install Adafruit_BBIO sudo apt-get install python-imaging python-smbus sudo apt-get install git git clone https://github.com/adafruit/Adafruit_Python_SSD1306.git cd Adafruit_Python_SSD1306 sudo python setup.py install
四 编写python程序测试显示屏
新建spioled.py:
import time
import Adafruit_GPIO.SPI as SPI
import Adafruit_SSD1306
import Image
import ImageDraw
import ImageFont
# Beaglebone Black pin configuration:
RST = 'P9_12'
# Note the following are only used with SPI:
DC = 'P9_15'
SPI_PORT = 1
SPI_DEVICE = 0
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()
# Create blank image for drawing.
# Make sure to create image with mode '1' for 1-bit color.
width = disp.width
height = disp.height
image = Image.new('1', (width, height))
# Get drawing object to draw on image.
draw = ImageDraw.Draw(image)
# Draw a black filled box to clear the image.
draw.rectangle((0,0,width,height), outline=0, fill=0)
# Draw some shapes.
# First define some constants to allow easy resizing of shapes.
padding = 2
shape_width = 20
top = padding
bottom = height-padding
# Move left to right keeping track of the current x position for drawing shapes.
x = padding
# Draw an ellipse.
draw.ellipse((x, top , x+shape_width, bottom), outline=255, fill=0)
x += shape_width+padding
# Draw a rectangle.
draw.rectangle((x, top, x+shape_width, bottom), outline=255, fill=0)
x += shape_width+padding
# Draw a triangle.
draw.polygon([(x, bottom), (x+shape_width/2, top), (x+shape_width, bottom)], outline=255, fill=0)
x += shape_width+padding
# Draw an X.
draw.line((x, bottom, x+shape_width, top), fill=255)
draw.line((x, top, x+shape_width, bottom), fill=255)
x += shape_width+padding
# Load default font.
font = ImageFont.load_default()
# Alternatively load a TTF font.
# Some other nice fonts to try: http://www.dafont.com/bitmap.php
#font = ImageFont.truetype('Minecraftia.ttf', 8)
# Write two lines of text.
draw.text((x, top), 'Hello', font=font, fill=255)
draw.text((x, top+20), 'World!', font=font, fill=255)
# Display image.
disp.image(image)
disp.display()
如果没任何问题的话执行该程序，应该就是执行了：
python spioled.py 或者 sudo python spioled.py
显示如下：
参考文章：
https://learn.adafruit.com/ssd1306-oled-displays-with-raspberry-pi-and-beaglebone-black/