WAVESHARE 2.13 Inch E-Paper Display HAT

Product Information

Specifications:

• Display: 2.13inch e-Paper HAT
• Resolution: 250 x 122 pixels
• Display Color: Black/White
• Grey Scale: 2
• Operating Voltage: 3.3V/5V
• Communication Interface: SPI
• Dot Pitch
• Refresh Time: 2s
• Refresh Power: 26.4mW (typ.)
• Standby Current: < 0.01uA

Product Usage Instructions

1. Connecting the e-Paper HAT to Raspberry Pi:
   Make sure your Raspberry Pi is powered off before connecting the e-Paper HAT. Connect the HAT to the Raspberry Pi’s GPIO pins following the manufacturer’s instructions.

2. Installing Necessary Libraries:
   Install the required libraries for the e-Paper display on your Raspberry Pi by following the installation instructions provided by the manufacturer.

3. Writing Code for Display:
   Write code to control the display on the e-Paper using the provided programming principles. Ensure that you define the pixels correctly to display the desired image or text.

4. Refreshing the Display:
   When refreshing the display, be mindful of not using partial refresh mode continuously. After multiple partial refreshes, perform a full refresh to avoid abnormal display effects.

5. Power Management:
   Do not keep the screen powered on for extended periods without refresh. Set the screen to sleep mode or power it off when not in use to prevent damage to the e-Paper display.

6. Maintenance:
   It is recommended to refresh the e-Paper display at least once every 24 hours if not in continuous use. Before storing the display for a prolonged period, clear the screen using the program provided.

Frequently Asked Questions (FAQ):

• Q: Can I modify the refresh speed of the e-paper display?
  A: Yes, you can modify the refresh speed by changing the waveform in EPD_2in13_V3.c as mentioned in the manual. Be cautious when altering parameters to avoid adverse effects on display quality.

• Q: What precautions should I take when using the e-Paper display?
  A: Follow the precautions provided in the manual, including avoiding continuous use of partial refresh mode, powering off the screen when not in use, and maintaining a proper refresh interval to prevent damage to the display.

Overview

• V4: fully compatible with V3; and it provides a demo that can realize a fast refreshing function.
• V3: The resolution is 250 × 122, and the hardware structure and interface of the V3 are compatible with the V2, and the V3 demo is adopted. If you purchase it for the first time, and there is a V3 label on the back of the screen, you can use the V3 demo directly.
• If you think the partial refreshing of the V3 is slow, you can modify the refresh speed by changing the waveform in EPD_2in13_V3.c. Reducing the parameters of the box in the following figure can improve the refresh speed (e.g., change 0x14 to 0x13), but pay attention to the parameter being too small, and the color of the partial refreshing will become lighter.
• V2: resolution is 250×122, V2 demo.

Parameters

• Refresh time: The refresh time is the experimental results, the actual refresh time will have errors, and the actual effect shall prevail. There will be a flickering effect during the global refresh process, this is a normal phenomenon.
• Power consumption: The power consumption data is the experimental results. The actual power consumption will have a certain error due to the existence of the driver board and the actual use situation. The actual effect shall prevail.

SPI Communication Timing

• CSB (CS): Slave chip select, when CS is low, the chip is enabled.
• SCL (SCK/SCLK): UART clock signal.
• D/C (DC): Data/command control pin, writes commands at a low level; writes data/parameter at a high level.
• SDA (DIN): Serial data signal.
• Timing: CPHL=0, CPOL=0 (SPI0)

Remarks
For more information about SPI, you can search for information online.

Working Principle
This product is an E-paper device adopting the image display technology of Microencapsulated Electrophoretic Display, MED. The initial approach is to create tiny spheres, in which the charged color pigments are suspended in the transparent oil and would move depending on the electronic charge. The E-paper screen displays patterns by reflecting the ambient light, so it has no background light requirement. Under ambient light, the E-paper screen still has high visibility with a wide viewing angle of 180 degrees. It is the ideal choice for E-reading.

Program Principle
We define the pixels in a monochrome picture, 0 is black and 1 is white.

• White: □: Bit 1
• Black：■: Bit 0
• The dot in the figure is called a pixel. As we know, 1 and 0 are used to define the color, therefore we can use one bit to define the color of one pixel, and 1 byte = 8pixels
• For example, If we set the first 8 pixels to black and the last 8 pixels to white, we show it by codes, they will be 16-bit as below:

For computers, the data is saved in MSB format:

So we can use two bytes for 16 pixels.

Precautions

1. For E-paper displays that support partial refresh, please note that you cannot refresh them with the partial refresh mode all the time. After refreshing partially several times, you need to fully refresh EPD once. Otherwise, the display effect will be abnormal, which cannot be repaired!
2. Note that the screen cannot be powered on for a long time. When the screen is not refreshed, please set the screen to sleep mode or power off it. Otherwise, the screen will remain in a high voltage state for a long time, which will damage the e-paper and cannot be repaired!
3. When using the e-Paper display, it is recommended that the refresh interval is at least 180 s, and refresh at least once every 24 hours. If the e-paper is not used for a long time, you should use the program to clear the screen before storing it. (Refer to the datasheet for specific storage environment requirements.)
4. After the screen enters sleep mode, the sent image data will be ignored, and it can be refreshed normally only after initializing again.
5. Control the 0x3C or 0x50 (refer to the datasheet for details) register to adjust the border color. In the demo, you can adjust the Border Waveform Control register or VCOM AND DATA INTERVAL SETTING to set the border.
6. If you find that the created image data is displayed incorrectly on the screen, it is recommended to check whether the image size setting is correct, change the width and height settings of the image, and try again.
7. The working voltage of the e-Paper display is 3.3V. If you buy the raw panel and you need to add a level convert circuit for compatibility with 5V voltage. The new version of the driver board (V2.1 and subsequent versions) has added a level processing circuit, which can support both 3.3V and 5V. The old version only supports a 3.3V working environment. You can confirm the version before using it. (The one with the 20-pin chip on the PCB is generally the new version.)
8. The FPC cable of the screen is fragile, Please note: Do not bend the cable along the vertical direction of the screen to avoid tearing the cable; Do not repeatedly excessively bend the line, to avoid line fracture; Do not bend the cable toward the front of the screen to prevent the cable from being disconnected from the panel. It is recommended to use fixed wiring during debugging and development.
9. The screen of the e-paper is relatively fragile, please try to avoid dropping, bumping, and pressing hard.
10. We recommend that customers use the sample program provided by us to test with the corresponding development board.

Working With Raspberry Pi

Hardware Connection

• When connecting the Raspberry Pi, you can directly insert the board into the 40PIN pin header of the Raspberry Pi, and pay attention to the correct pins.
• If you choose to connect with an 8PIN cable, please refer to the pin correspondence table below:

Raspberry Pi Pinout

Enable SPI Interface
Open the Raspberry Pi terminal and enter the following command in the config interface:

sudo raspi-config
Choose Interfacing Options -> SPI -> Yes Enable SPI interface.

Then reboot your Raspberry Pi:
sudo reboot

• Check /boot/config.txt, and you can see ‘dtparam=spi=on’ was written in.
• To make sure SPI is not occupied, it is recommended to close other drivers’ coverage. You can use ls /dev/spi* to check whether SPI is occupied. If the terminal outputs /dev/spidev0.1 and /dev/spidev0.1, SPI is not occupied.

C

• Install lg library:
  #Open the Raspberry Pi terminal and run the following commands:
  wget https://github.com/joan2937/lg/archive/master.zip
  unzip master.zip
  cd lg-master
  make
  sudo make install

  For more details, you can refer to: https://github.com/gpiozero/lg.

• Install gpiod library (Optional):

  Open the Raspberry Pi terminal and run the following commands:

  sudo apt-get update
  sudo apt install gpiod libgpiod-dev

• Install BCM2835:

  Open the Raspberry Pi terminal and run the following command

  wget http://www.airspayce.com/mikem/bcm2835/bcm2835-1.71.tar.gz
  tar zxvf bcm2835-1.71.tar.gz
  cd bcm2835-1.71/
  sudo ./configure && sudo make && sudo make check && sudo make install

  For more information, please refer to the official website:

  http://www.airspayce.com/mikem/bcm2835/.

• Install WiringPi (Optional):

  Open the Raspberry Pi terminal and run the following command:

  sudo apt-get install wiringpi

  For Raspberry Pi systems after May 2019 (earlier than before, you may not

  need to execute), you may need to upgrade:
  wget https://project-downloads.drogon.net/wiringpi-latest.deb
  sudo dpkg -i wiringpi-latest.deb
  gpio -v

  Run gpio -v and version 2.52 will appear. If it does not appear, the

  installation is wrong.

  Bullseye branch system uses the following command:

  git clone https://github.com/WiringPi/WiringPi
  cd WiringPi
  ./build
  gpio -v

  Run gpio -v and version 2.60 will appear. If it does not appear, it means

  that there is an installation error.

• Download the demo via GitHub (You can skip this step if you have downloaded it.)
  git clone https://github.com/waveshare/e-Paper.git
  cd e-Paper/RaspberryPi_JetsonNano/

• Download the demo (You can skip this step if you have downloaded it.)
  wget https://files.waveshare.com/upload/7/71/E-Paper_code.zip
  unzip E-Paper_code.zip -d e-Paper
  cd e-Paper/RaspberryPi_JetsonNano/

• Compile the demo (Note: -j4 is to compile with 4 threads, the numbers can be modified by yourself; EPD=epd2in13V3 is to specify a macro definition, and epd2in13V3 corresponds to the test demo in the main function).

  Now at e-Paper/RaspberryPi_JetsonNano

  cd c
  sudo make clean
  sudo make -j4 EPD=epd2in13V3

• Run the demo:
  sudo ./epd

Python

• Install the function library:
  sudo apt-get update
  sudo apt-get install python3-pip
  sudo apt-get install python3-pil
  sudo apt-get install python3-numpy
  sudo pip3 install RPi.GPIO
  sudo pip3 install spidev

• Install function library (python2):
  sudo apt-get update
  sudo apt-get install python-pip
  sudo apt-get install python-pil
  sudo apt-get install python-numpy
  sudo pip install RPi.GPIO
  sudo pip install spidev

• Install gpiozero library (it is installed in the system by default, if not, you can install it by following the commands below):
  sudo apt-get update

  python3

  sudo apt install python3-gpiozero

  python2

  sudo apt install python-gpiozero

• Download the demo via GitHub (You can skip this step if you have downloaded it.)
  git clone https://github.com/waveshare/e-Paper.git
  cd e-Paper/RaspberryPi_JetsonNano/

• Download the demo (You can skip this step if you have downloaded it.)
  wget https://files.waveshare.com/upload/7/71/E-Paper_code.zip
  unzip E-Paper_code.zip -d e-Paper
  cd e-Paper/RaspberryPi_JetsonNano/

• Run the demo:

  Make sure it’s in e-Paper/RaspberryPi_JetsonNano/

  cd python/examples/
  python3 epd_2in13_V3_test.py

Working With Arduino

Hardware Connection
Use an 8PIN cable to connect, please refer to the pin correspondence table below:

Connect To Arduino

e-Paper

| Arduino UNO|

Mega2560

---|---|---
VCC| 5V| 5V
GND| GND| GND
DIN| D11| D51
CLK| D13| D52
CS| D10| D10
DC| D9| D9
RST| D8| D8
BUSY| D7| D7

Install IDE
Arduino IDE Windows Install Guide

Run The Demo

• Download the demo in Resource, unzip it to the “E-Paper_code” directory, and you can see the following content:
• Open the test demo: E-Paper_code\Arduino\epd2in13_V3\epd2in13_V3.ino
• Select the corresponding Board and Port in the Tools in the Arduino IDE.
• Finally, click upload, the upload is successful as follows (Arduino 1.8.13).

Working With Jetson Nano

Hardware Connection
The 40PIN pin of Jetson Nano is compatible with the 40PIN pin of Raspberry Pi and provides a Jetson.GPIO library with the same API as the RPI.GPIO library of Raspberry Pi, so the serial number connected here is the same as that of Raspberry Pi. The module can be directly inserted into the 40Pin headers of the Jetson Nano when using the 40PIN interface. If you choose to connect with an 8PIN cable, please refer to the pin correspondence table below:

Connect to Jetson nano

C

• Download the demo via GitHub (you can skip this step if you have downloaded it.)
  git clone https://github.com/waveshare/e-Paper.git
  cd e-Paper/RaspberryPi_JetsonNano/

• Download the test demo: (you can skip this step if you have downloaded it.)
  wget https://files.waveshare.com/upload/7/71/E-Paper_code.zip
  unzip E-Paper_code.zip -d e-Paper
  cd e-Paper/RaspberryPi_JetsonNano/

• Compile the demo (Note: JETSON is the specified device, and RPI is not specified by default. -j4 is to compile by 4 threads, and the number can be changed by yourself. “EPD=epd2in13V3” is to specify a macro definition, and “epd2in13V3” corresponds to the test demo in the main function.)

  Now at e-Paper/RaspberryPi_JetsonNano

  cd c
  sudo make clean
  sudo make JETSON -j4 EPD=epd2in13V3

• Run the demo
  sudo ./epd

Python

• Install function library:
  sudo apt-get update
  sudo apt-get install python3-numpy
  sudo apt-get install python3-pip
  sudo pip3 install Jetson.GPIO

• Download the demo via GitHub (you can skip this step if you have downloaded it.)
  git clone https://github.com/waveshare/e-Paper.git
  cd e-Paper/RaspberryPi_JetsonNano/

• Download the demo (you can skip this step if you have downloaded it.)
  wget https://files.waveshare.com/upload/7/71/E-Paper_code.zip
  unzip E-Paper_code.zip -d e-Paper
  cd e-Paper/RaspberryPi_JetsonNano/

• Run the demo:

  Make sure it’s in e-Paper/RaspberryPi_JetsonNano/

  cd python/examples/
  python3 epd_2in13_V3_test.py

Working With Sunrise X3 Pi

Hardware Connection

• When connecting the Sunrise X3 Pi, you can directly insert the board into the 40PIN pin header of the Sunrise X3 Pi, and pay attention to the correct pins.
• If you choose to connect with an 8PIN cable, please refer to the pin correspondence table below:

Connect to Sunrise X3 Pi

Enable SPI

• SPI is enabled by default. If you have disabled it, you can enable it by following the steps below.
• Enter the command: sudo srpi-config

Python

• The corresponding library has been installed in the function. If you uninstall it accidentally, please use the following command to install it.
  sudo apt-get update
  sudo apt-get install python-pip
  sudo apt-get install python-pil
  sudo apt-get install python-numpy
  sudo pip install Hobot.GPIO
  sudo pip install spidev

• Download the demo via GitHub (skip this step if you have downloaded it).
  git clone https://github.com/waveshare/e-Paper.git
  cd e-Paper/RaspberryPi_JetsonNano/

• Download the demo (skip this step if you have downloaded it).
  wget https://files.waveshare.com/upload/7/71/E-Paper_code.zip
  unzip E-Paper_code.zip -d e-Paper
  cd e-Paper/RaspberryPi_JetsonNano/

• Run the demo

  Make sure you are in e-Paper/RaspberryPi_JetsonNano/

  cd python/examples/
  python3 epd_2in13_V3_test.py

Working With STM32

Hardware Connection

Connect to STM32

e-Paper|

STM32

---|---
VCC| 3.3V
GND| GND
DIN| PA7
CLK| PA5
CS| PA4
DC| PA2
RST| PA1
BUSY| PA3

Run The Demo

• Click to download the demo, and then unzip it into the E-Paper_code directory to see the following content.
• Use Keil to open epd-demo.uvprojx in the E-Paper_code\STM32\STM32-F103ZET6\MDK-ARM directory.
• Open Keil’s compilation toolbar (usually already open).
• Select the EPD_2in13_V3_test at the location shown in the picture.
• Click to compile.
• Make sure the appropriate programmer is connected, then click LOAD to download the demo to the microcontroller.

ESP32/8266

• ESP32
  There is a lot of content, please click here to view.

• ESP8266
  There is a lot of content, please click here to view.

Resources

Document

• 2.13inch_e-Paper_HAT_Schematic diagram.pdf
• 2.13inch e-Paper Specification V4 （Newest）
• 2.13inch e-Paper Specification V3
• 2.13inch e-Paper Specification V2
• 2.13inch e-Paper Datasheet V1 version

Demo code

• Demo (zip)
• Github

Development Resources

• E-Paper Floyd-Steinberg
• Image2Lcd.7z
• Image2Lcd Image Modulo
• Zimo221.7z
• E-Paper API Analysis

Related Resources

• Raspberry Pi Documentation

FAQs

Question about Software

• Question:
  The Raspberry Pi runs the Python program and the following occurs?

• Answer:

  • Enter the command: ls /dev/spi*
  • The result may appear as shown in the figure.
  • This is because the SPI interface is occupied in the /boot/config.txt file.
  • Steps:
  • Delete the occupation of spi0-0 in the /boot/config.txt file.
  • Modify the location shown in the picture in the /e-Paper/RaspberryPi_JetsonNano/lib/waveshare_epd/epdconfig.py file and change it to 0,1.

• Question:
  stm32 drives the e-paper screen, the MDK compilation display space is not enough.
  Answer:
  Our demo uses stm32f103zet6. If the customer modifies other models in MDK, such as stm32f103rbt6, the RAM space becomes smaller, and the stack size and heap size in the startup file need to be modified on the original basis.

• Question:
  After multiple positions are brushed, the font is lighter after brushing several times.
  Answer:
  In this case, the customer needs to reduce the position of the round brush and clear the screen after 5 rounds of brushing (increasing the voltage of VCOM can improve the color, but it will increase the afterimage).

• Question:
  When the e-paper screen is in deep sleep mode, there will be a problem that the screen refresh will not be clean when it wakes up for the first time. How can I solve it?
  Answer:
  The process of re-awakening the e-ink screen is the process of re-powering. Therefore, when the EPD wakes up, the screen must be cleared first, to avoid the afterimage phenomenon to the greatest extent.

• Question:
  When testing the demo, it has been stuck in e-Paper busy.
  Answer:
  It may be caused by the unsuccessful SPI driver.

1. First, check whether the wiring is correct.
2. Check whether the spi is turned on and whether the parameters are configured correctly (spi baud rate, spi mode, and other parameters).

• Question:
  Why can’t the image be displayed after full brushing?
  Answer:
  The full refresh initialization function needs to be added when the ink screen is switched from partial refresh to full refresh.

• Question:
  Why is the printing information normal when running a Python program, but the ink screen does not respond?
  Answer:
  It may be a demo based on the BCM2835 library that has run the C language before. At this time, you need to restart the Raspberry Pi and then run the Python demo.

• Question:
  ImportError: No module named Image?
  Answer:
  Install the imaging library using the command sudo apt-get install python- imaging

• Question:
  When to transmit Data Start Transmission 1 and when to use Data Start Transmission 2. In KW mode, what is “OLD” data and what is “NEW” data. ?
  Answer:
  If it is a three-color screen, when you need to transmit B/W data, use Data Start Transmission 1, when transmitting RED data, use Data Start Transmission 2, because the 2.13inch e-Paper HAT (D) can only display black and white, Therefore, when working in KW mode Data Start Transmission 1, the last data is sent, that is, the so-called old, and 0x00 is directly sent in the program. When Data Start Transmission 2, the data that needs to be refreshed, the so- called “NEW” is sent. data.

• Question:
  The e-paper display is too dark or too light?
  Answer:
  You can adjust the value of Vcom in the program to change the display contrast and the screen improvement effect with local brushing is particularly obvious.

• Question:
  Does the e-paper show a black border?
  Answer:
  The border display color can be set through the Border Waveform Control register or the VCOM AND DATA INTERVAL SETTING register.

• Question:
  When the ink screen is in deep sleep mode, the first time the screen refreshes will be unclean. How can I solve it?
  Answer:
  The process of re-awakening the e-paper screen is the process of supplying the power again. Therefore, when the EPD wakes up, it must first clear the screen, so as to avoid the afterimage phenomenon to the greatest extent.

Question about Hardware

• Question:
  Can Arduino 5V drive the ink screen?
  Answer:
  Yes, now there is a level conversion chip onboard, supporting a 5V drive.

• Question:
  What should be paid attention to when designing the driver board?
  Answer:

  • The rated input voltage of the e-paper screen is 2.3~3.6V. If it is a 5V system, level conversion is required. In addition, the voltage should not be lower than 2.5V, so as not to affect the display effect of the e-paper screen.
  • Device selection can use the model in the schematic diagram we provide or choose according to the datasheet.

• Question:
  Can I use analog SPI?
  Answer:
  Yes, pay attention to the correct timing.

• Question:
  Why is the BUSY pin always busy?
  Answer:

  • Check if SPI communication is normal.
  • Confirm whether the BUSY pin is normally initialized to input mode.
  • It may be that there is no normal reset, try to shorten the duration of the low level during reset (because the power-off switch is added to the drive circuit, the reset low level is too long, which will cause the drive board to power off and cause the reset to fail).
  • If the busy function sends the 0x71 command, you can try to comment it out.

• Question:
  What is the specification of the screen cable interface?
  Answer:

  • 1.64inch, 2.36inch, 3inch, 0.5mm pitch, 26Pin.
  • 1.02inch, 0.5mm pitch, 30Pin.
  • 4.37inch, 7.3inch, 0.5mm pitch, 50Pin.
  • The rest (non-parallel ports) are 0.5mm pitch, 24Pin.

• Question:
  What type of connector does the ink screen use?
  Answer:
  Cable socket 0.5-24pin rear-flip 2.0H (FPC connector).

Question about Screen

• Question:
  What is the usage environment of the e-paper screen?
  Answer:

  • 【Working conditions】Temperature range: 0~50°C; Humidity range: 35%~65%RH.
  • 【Storage conditions】Temperature range: below 30°C; Humidity range: below 55%RH; Maximum storage time: 6 months.
  • 【Transportation conditions】Temperature range: -25~70°C; Maximum transportation time: 10 days.
  • 【After unpacking】Temperature range: 20°C±5°C; Humidity range: 50±5%RH; Maximum storage time: Assemble within 72 hours.

• Question:
  Precautions for E-paper screen refresh
  Answer:

  • Refresh mode
  • Full refresh: The e-paper screen will flicker several times during the refresh process (the number of flickers dependson the refresh time), and the flicker is to remove the afterimage to achieve the best display effect.
  • Partial refresh: The e-paper screen has no flickering effect during the refresh process. Users who use the partialbrushing function note that after refreshing several times, a full refresh operation should be performed to remove theresidual image, otherwise the residual image problem will become more and more serious, or even damage the screen(currently only some black and white e-paper screens support partial refreshing, please refer to product pagedescription).
  • Refresh rate
  • During use, it is recommended that customers set the refresh interval of the e-paper screen to at least 180 seconds(except for products that support the local brush function).
  • During the standby process (that is, after the refresh operation), it is recommended that the customer set the e-paper screen to sleep mode, or power off (the power supply part of the e-paper screen can be disconnected with an analog switch) to reduce power consumption and prolong the life of the e-paper screen. (If some e-paper screens are powered on for a long time, the screen will be damaged beyond repair.)
  • During the use of the three-color e-paper screen, it is recommended that customers update the display screen at least once every 24 hours (if the screen remains the same screen for a long time, the screen burn will be difficult to repair).
  • Application
    The e-paper screen is recommended for indoor use. If it is used outdoors, it is necessary to avoid direct sunlight on the e-paper screen, and at the same time, take UV protection measures, because charged particles will dry out under strong light for a long time, resulting in loss of activity and failure to refresh. This situation is irreversible. When designing e-paper screen products, customers should pay attention to determining whether the use environment meets the requirements of an e-paper screen.

• Question:
  What is the refresh rate/lifetime of the e-paper screen?
  Answer:
  Ideally, with normal use, it can be refreshed 1,000,000 times (1 million times).

• Question:
  After using it for some time, the screen refresh (full refresh) has a serious afterimage problem that cannot be repaired.
  Answer:
  Power on the development board for a long time, after each refresh operation, it is recommended to set the screen to sleep mode or directly power off processing, otherwise, the screen may burn out when the screen is in a high voltage state for a long time.

• Question:
  After the e-paper screen enters deep sleep mode, can it be refreshed again?
  Answer:
  Yes, but you need to re-initialize the electronic paper with software.

• Question:
  Why is the image displayed offset?
  Answer:

  • Maybe the SPI rate is too high, resulting in data loss, try to reduce the SPI rate.
  • Insufficient or unstable power supply leads to data loss.
  • The data cable is too long to cause data loss, the extension cable should not exceed 20cm.

• Question:
  What is the waveform file of the e-paper screen and what does it do?
  Answer:
  The display gray scale of electrophoretic electronic paper is determined by the spatial position of the particles in the Microcapsule or Microcup. The electrophoresis phenomenon occurs between black particles and white particles under the action of voltage. This voltage sequence that promotes the electrophoretic movement of the particles is the driving force of the electronic paper. waveform. The driving waveform is the core part of the electronic paper display, and the optimization of the driving waveform will directly affect the display effect of the display. The driving waveform file is used to describe the parameters formed by the voltage sequence that promotes the electrophoretic movement of the particles, and it needs to be called regularly when the electronic paper is refreshed. Different batches of e-paper diaphragms and electrophoretic matrices require different voltage values when driving the display due to materials, manufacturing processes, etc. The waveform of the e-paper screen is reflected in the relationship between grayscale, voltage, and temperature. Generally speaking, after each batch of electrophoresis matrix is generated, there will be a corresponding waveform file in the form of a .wbf file. The film manufacturer will provide the waveform file and electrophoresis matrix to the manufacturer of the electronic paper screen, and then the manufacturer of the electronic paper screen integrates the protection board, substrate, and driver and then provides it to customers; if the waveform file does not correspond to the screen, likely, the display cannot be displayed or the display effect is unsatisfactory. Generally, the waveform file has OTP built into the driver IC of the ink screen when leaving the factory, and some programs we provide also called external waveform files to drive the e-paper screen.

• Question:
  What do LUT and OTP stand for?
  Answer:
  LUT is the abbreviation of LOOK UP TABLE, and OTP is the abbreviation of ONE TIME PROGRAM. The original intention of LUT is to load waveform files, and the waveform files are divided into OTP and REGISTER. Among them, OTP is the built-in waveform storage method and REGISTER is the external waveform storage method.

• Question:
  What is the process of refreshing the e-paper partially?
  Answer:

  • There are mainly two types of ink screens.
  • One is to refresh the background image first.
  • The other is to alternately refresh old data and new data.

• Question:
  How to refresh in different positions at the same time?
  Answer:
  Simultaneous brushing in different locations needs to be operated in the program design, that is, first brushing the data of different locations into the electronic paper IC, and finally doing the Update/TurnOnDisplay uniformly.

• Question:
  Are bare screens shipped with a film?
  Answer:
  with film.

• Question:
  Does the e-paper have a built-in temperature sensor?
  Answer:
  pins.

• Question:
  What is the pitch of the 8-pin connectors on the E-Ink display hats?
  Answer:
  The pitch of the 8-pin connectors on the E-Ink display hats is 0.1 inch (2.54 mm).

Support

Technical Support
If you need technical support or have any feedback/review, please click the Submit Now button to submit a ticket, Our support team will check and reply to you within 1 to 2 working days. Please be patient as we make every effort to help you to resolve the issue. Working Time: 9 AM – 6 AM GMT+8 (Monday to Friday)

References

• airspayce.com/mikem/bcm2835/bcm2835-1.71.tar.gz
• GitHub - gpiozero/lg: Linux C libraries and Python modules for manipulating GPIO
• GitHub - waveshareteam/e-Paper
• GitHub - WiringPi/WiringPi: The arguably fastest GPIO Library for the Raspberry Pi
• project-downloads.drogon.net/wiringpi-latest.deb

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