Dependencies
Before using the library you will need to make sure you have a few dependencies installed. Connect to your device using SSH and follow the steps below.
If you're using a Raspberry Pi, install the RPi.GPIO library by executing:sudo apt-get install python-pip python-dev build-essentialsudo pip install RPi.GPIO
If you're using a Beaglebone Black, install the Adafruit_BBIO library by executing:sudo apt-get install python-pip python-dev build-essentialsudo pip install Adafruit_BBIO
Finally, on both the Raspberry Pi and Beaglebone Black install the Python Imaging Library by executing:sudo apt-get install python-imaging
Now to download and install the Nokia LCD python library code and examples, execute the following commands:sudo apt-get install gitgit clone https://github.com/adafruit/Adafruit_Nokia_LCD.gitcd Adafruit_Nokia_LCDsudo python setup.py install
Raspberry Pi SPI Setup
If you haven't done so already with your Pi, make sure to edit the blacklist.conf file to comment the line which disables SPI. Reboot your Pi and you should see the files /dev/spidev0.0 and /dev/spidev0.1 are now available.
Beaglebone Black Device Tree Setup
If you're using the Beaglebone Black you'll need to make sure you enable the SPI ports by manipulating the device tree. The easiest way to setup the device tree is to automatically enable a built-in SPI overlay on boot.
With the Beaglebone Black connected to your computer over USB, open the USB mass storage drive named 'boot' and edit the file uEnv.txt on the drive. Add the following line to the file:optargs=capemgr.enable_partno=BB-SPIDEV0
NOTE: Be careful editing the uEnv.txt file on Windows, as changing the line endings can cause your BeagleBone Black not to boot and require an OS reinstall! The safest option is to connect to the BeagleBone Black in a command window andfollow the steps at the end of this page to mount and edit uEnv.txt on the BeagleBone Black.
Reboot your device and you should see the files /dev/spidev1.0 and /dev/spidev1.1 now exist.
Usage
Inside the examples subdirectory you'll find python scripts which demonstrate the usage of the library. To help you get started, I'll walk through the shapes.py code below:
import time import Adafruit_Nokia_LCD as LCD import Adafruit_GPIO.SPI as SPI import Image import ImageDraw import ImageFont
# Raspberry Pi hardware SPI config: DC = 23 RST = 24 SPI_PORT = 0 SPI_DEVICE = 0 # Raspberry Pi software SPI config: # SCLK = 4 # DIN = 17 # DC = 23 # RST = 24 # CS = 8 # Beaglebone Black hardware SPI config: # DC = 'P9_15' # RST = 'P9_12' # SPI_PORT = 1 # SPI_DEVICE = 0 # Beaglebone Black software SPI config: # DC = 'P9_15' # RST = 'P9_12' # SCLK = 'P8_7' # DIN = 'P8_9' # CS = 'P8_11'
The first block defines configuration for using a Raspberry Pi with hardware SPI as shown in the diagram on the previous page. Below this block is a commented out block which sets the pins for using software SPI.
Similarly the last commented sections show the pins and ports for using the Beaglebone Black, both with hardware SPI and software SPI.
Uncomment and comment the pins appropriately to match your hardware configuration.
# Hardware SPI usage: disp = LCD.PCD8544(DC, RST, spi=SPI.SpiDev(SPI_PORT, SPI_DEVICE, max_speed_hz=4000000)) # Software SPI usage (defaults to bit-bang SPI interface): #disp = LCD.PCD8544(DC, RST, SCLK, DIN, CS) # Initialize library. disp.begin(contrast=60) # Clear display. disp.clear() disp.display()
Note that the SPI_PORT and SPI_DEVICE values point to a spidev hardware SPI device at /dev/spidev{port}.{device} in the filesystem, like /dev/spidev0.0 in this case. Also notice the speed of SPI communication is set to 4mhz, the maximum speed for the LCD.
The commented line that follows demonstrates how to create an instance of the LCD class using software SPI. In this case the pin values for the LCD's DC, RST, SCLK, DIN, and CS pins must be specified instead of an SPI class instance.
Once the display is created it is initialized by calling begin(), and then cleared and drawn using the clear() and display() functions.
# Create blank image for drawing.
# Make sure to create image with mode '1' for 1-bit color.
image = Image.new('1', (LCD.LCDWIDTH, LCD.LCDHEIGHT))
# Get drawing object to draw on image.
draw = ImageDraw.Draw(image)
# Draw a white filled box to clear the image.
draw.rectangle((0,0,LCD.LCDWIDTH,LCD.LCDHEIGHT), outline=255, fill=255)
# Draw some shapes.
draw.ellipse((2,2,22,22), outline=0, fill=255)
draw.rectangle((24,2,44,22), outline=0, fill=255)
draw.polygon([(46,22), (56,2), (66,22)], outline=0, fill=255)
draw.line((68,22,81,2), fill=0)
draw.line((68,2,81,22), fill=0)
# Load default font.
font = ImageFont.load_default()
# Alternatively load a TTF font.
# Some nice fonts to try: http://www.dafont.com/bitmap.php
# font = ImageFont.truetype('Minecraftia.ttf', 8)
# Write some text.
draw.text((8,30), 'Hello World!', font=font)
# Display image.
disp.image(image)
disp.display()
To display text, a default font is loaded and text commands are made on the draw class. If you have a TrueType font available you can even load it to display a custom font.
Once drawing on an image is complete, it's displayed on the LCD by calling the image() function to copy the image data to the LCD buffer, and the display() function to send the buffer to the display.
That's all the code you need to start drawing graphics on the LCD!
To run the example execute the following command:
sudo python shapes.py
Examine and run the other example files such as image.py to see how to load and display an image file, or animate.py to see a simple text animation.
Enjoy using your Nokia LCD with a Raspberry Pi or Beaglebone Black! If you run into problems with the library or wish to contribute to it, feel free to raise issues and send pull requests to the library's home on github.
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