Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
Branch: master

[PlatformWithOS] speed up gpio_test and allow epd_test to terminate o…

…n a specific image

(by specifying image count)

Signed-off-by: Christopher Hall <christopherhall.hsw@gmail.com>
latest commit e3e34fb013
Christopher Hall authored

README.md

E-Ink Driver for: Raspberry Pi / BeagleBone Black

Driver Programs - Directory "driver-common"

  • gpio_test - simple test for GPIO driver
  • epd_test - test program for direct driving EPD panel
  • epd_fuse - present EPD as a file for easy control

Extra item for BeagleBone

The program uses device tree files to access the GPIOs, so Install the necessary firware files from: https://github.com/nomel/beaglebone

git clone https://github.com/nomel/beaglebone.git
cp -p beaglebone/gpio-header/generated/gpio-P9.* /lib/firmware

Note: There is a README-BeagleBoneBlack.md that you should also read as it explains the update of the Angstomsystem on the SD Car in more detail.

Compiling

These test programs should compile with no additional libraries, but the EPD driver needs the fuse development library installed.

# Raspberry Pi
sudo apt-get install libfuse-dev
# BeagleBone Black
sudo opkg install libfuse-dev

GPIO Test

Connect three LEDs each with a limiting resistor (1k..2k); the resistor connects from an expansion connector pin to the anode of an LED. Two of the LEDs will flash and the third will brighten and dim.

Pin connections

LED R Pi B B B Description


LED_BLUE P1_23 P9_15 Flashes on/off LED_WHITE P1_21 P9_23 Fashes off/on LED_PWM P1_12 P9_14 Brightens and dims

Build and run using:

make rpi-gpio_test  # bb-gpio_test
sudo ./driver-common/gpio_test

EPD Test

This will first clear the panel then display a series of images (all 2.0" images from Arduino example). This need the Linux SPI module installed.

Raspberry Pi: Build and run using:

sudo modprobe spi-bcm2708
make rpi-epd_test
sudo ./driver-common/epd_test

BeagleBone Black: Build and run using:

make bb-epd_test
sudo ./driver-common/epd_test

EPD fuse

This allows the display to be represented as a virtual director of files, which are:

File Read/Write Description


version Read Only The driver version number panel Read Only String describing the panel and giving its pixel width and height current Read Only Binary image that matches the currently displayed image (big endian) display Read Write Image being assembled for next display (big endian) temperature Read Write Set this to the current temperature in Celsius command Write Only Execute display operation BE Directory Big endian version of current and display LE Directory Little endian version of current and display

Command Byte Description


'C' 0x43 Clear the EPD, set current to all zeros, display is not affected 'U' 0x5A Erase current from EPD, output display to EPD, copy display to current

Notes:

  • The default bit ordering for the display is big endian i.e. the top left pixel is the value 0x80 in the first byte.
  • The BE directory is the same as the root current and display.
  • The LE directory current and display reference the top left pixel as 0x01 in the first byte.
  • The current_inverse and display_inverse represent black as zero (0) and white as one (1) while those item without the suffix represent the display's natural coding (0=>white, 1=>black)
  • The particular combination of BE/display_inverse is used in the Python EPD demo since it fits better with the Imaging library used.

Build and run using:

make rpi-epd_fuse          # bb-epd_fuse
sudo modprobe spi-bcm2708  # not on BeagleBone Black (note below)
sudo mkdir /tmp/epd
sudo ./driver-common/epd_fuse --panel=2.0 -o allow_other -o default_permissions /tmp/epd
cat /tmp/epd/version
cat /tmp/epd/panel
echo C > /tmp/epd/command
./driver-common/xbm2bin < cat_2_0.xbm > /tmp/epd/display
echo U > /tmp/epd/command
# try displaying other images
# to shut down:
sudo umount -f /tmp/fuse
rmdir /tmp/fuse

Note: On the BeagleBone firmware is loaded to enable the SPI

Starting EPD FUSE at Boot

Need to install the startup script in /etc/init.d and install the EPD FUSE program in /usr/sbin, there is a make target that does this.

sudo make rpi-install   # bb-install
sudo service epd-fuse start
ls -l /dev/epd
# to stop
sudo service epd-fuse stop
# to remove
sudo make remove

Python Demo Programs - directory "demo"

These need the PIL library installed:

# Raspberry Pi
sudo apt-get install python-imaging
# BeagleBone Black
sudo opkg install python-imaging

Drawing Demo

Draw some lines, graphics and text

python demo/DrawDemo.py

Image demo

  • Accepts a lists of image files on the command line.
  • Converts them to grey scale to ensure formats like PNG, JPEG and GIF will work.
  • Inverts the image since the E-Ink panel is reverse (i.e. black on white).
  • Converts image to single bit (PIL "1" mode).
  • Display the middle of the image (using crop function).
  • Delay.
  • Display the re-sized image.
  • Delay before fetching next file.

Note if scratch is installed on the system, the following commands will show some cartoon animals. The images when re-sized will be distorted if the aspect ration of the original image is not the same as the display.

python demo/ImageDemo.py /usr/share/scratch/Media/Costumes/Animals/cat*
python demo/ImageDemo.py /usr/share/scratch/Media/Costumes/Animals/d*.png

Twitter Demo

Setup easy_install and use it to get pip, then use pip to get tweepy. Copy the sample configuration an edit to include your authentication information. Rather than using the basic authentication it is better to set up a Twitter App and generate a token for this. The token generation is quick at https://dev.twitter.com/. After creating the App,just click the button to create an access token.

Use Ctrl-C to stop this program.

# Raspberry Pi
sudo apt-get install python-setuptools
sudo easy_install pip
# BeagleBone Black
opkg install python-pip python-setuptools
# All
sudo pip install tweepy
# setup the config
cp tweepy_auth.py-SAMPLE tweepy_auth.py
# *** edit the config
# run the demo (this watches for linux)
python demo/TwitterDemo.py linux

Partial Demo

Display random overlapping rectangles using partial update. First argument is number of rectangle to generate before updating the EPD, second number is the number of frames to display before the program exits.

python demo/PartialDemo.py 3 20

Counter Demo

Display a 4 digit hex counter uses partial update to only change the updated digits. This will look somewhat strange as the display inversion will make the counter appear to go through a sequence like: 0000 0001 0000 0001 ...delay... 0001 0002 0001 0002

Use Ctrl-C to stop this program.

python demo/CounterDemo.py 3 20

E-Ink Panel Board Connections

This is for connection to the Evaluation board.

Pin Number Description Colour Raspberry Pi BeagleBone Black


  1. Vcc 3V Red P1-01 P9-03
  2. (LED1) White -
  3. (UART_RX) Grey -
  4. (UART_TX) Purple -
  5. (SW2) Blue -
  6. Temperature Green - (ext ADC required) -?- P9-39 (not yet)
  7. SPI_CLK Yellow P1-23 P9-22
  8. BUSY Orange P1-22 P9-27
  9. PWM Brown P1-12 P9-14
  10. /RESET Black P1-18 P9-26
  11. PANEL_ON Red P1-16 P9-12
  12. DISCHARGE White P1-10 P9-23
  13. BORDER_CONTROL Grey P1-08 P9-15
  14. SPI_MISO Purple P1-21 P9-21
  15. SPI_MOSI Blue P1-19 P9-18
  16. (RST/SBWTDIO) Green - -
  17. (TEST/SBWTCK) Yellow - -
  18. /FLASH_CS Orange P1-26 - Vcc P9-04
  19. /EPD_CS Brown P1-24 P9-17
  20. GND Black P1-25 P9-01

TO DO / BUGS

  • Verify the compensation timer.

  • Other demos, perhaps.

Something went wrong with that request. Please try again.