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{{Infobox item
|name=4.2inch e-Paper
|name2=4.2inch e-Paper Module
|img=[[File:4.2inch-e-Paper-1.jpg|300px|{{Amazon_nolink|default={{#ifeq: {{#urlget:amazon|0}}|{{#urlget:Amazon|0}}| default|}}|url=link=}}]]
|img2=[[File:4.2inch-e-paper-module-5.jpg|300px|{{Amazon_nolink|default={{#ifeq: {{#urlget:amazon|0}}|{{#urlget:Amazon|0}}| default|}}|url=link=}}]]
|caption=400x300, 4.2inch EPD panel
|caption2=400x300, 4.2inch EPD module, SPI interface
|category=[[:Category:OLEDs / LCDs|OLEDs / LCDs]], [[:Category:LCD|LCD]]
|{{#ifeq: {{#urlget:amazon|0}}|{{#urlget:Amazon|0}}| default|}}=display
|website_cn=[ 官方中文站点]
|website_en=[ Waveshare website]
{{Product List|OLEDs / LCDs/e-Paper}}
<div class="tabber">
<div class="tabbertab" title="Introducton">
{{E-Paper Raw Panel}}
400x300, 4.2inch EPD (Electronic Paper Display) module, SPI interface
<div style="background-color: #343434;text-align: center;color: white;padding: 20px;margin: 8px;">
=4.2inch e-Paper Module Manual=
|content =
|heading = Introduction
|content = Parameters, principles and precautions}}
{{Amazon|{{#ifeq: {{#urlget:amazon|0}}|{{#urlget:Amazon|0}}| default|}}=display
{{StudyCard|img=[[File:Rapberry Pi.jpg|110px|link=]]
|More = [ More]}}
|heading = Working with Raspberry Pi
|content = User guides for the development demo of C language, Python}}
|heading = Working with the Arduino
*Outline dimension(screen): 90.1mm x 77.0mm x 1.18mm
|content = User guides for the development demo based on Arduino UNO R3}}
*Outline dimension(driver board): 103.0mm x 78.5mm
*Display dimension: 84.8mm x 63.6mm
*Working voltage:3.3V/5V
*Communication interface: SPI
*Pixel pitch: 0.212 x 0.212
*Resolution: 400*300
*Display color: Black, White
*Gray level: 4
*Full refresh: 4s
*Refresh Power Consumption: 26.4mW(typ.)
*Sleep current: <0.01uA(close to0)
1.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
<br />
2.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.<br />
==SPI Communication Timing==
{{StudyCard|img=[[File:Jetson Arduino00.jpg|110px|link=]]
|heading = Working with the Jetson Nano
|content = User guides for the development demo of C language, Python}}
Since the ink screen only needs to be displayed, the data cable (MISO) sent from the machine and received by the host is hidden here.
{{StudyCard|img=[[File:Sunrise X3 Pi.jpg|110px|link=]]
*CS: Slave chip select, when CS is low, the chip is enabled
|heading = Working with Sunrise X3 Pi
*DC: data/command control pin, write command when DC=0; write data when DC=1
|content = User guides for the development demo based on Python}}
*SCLK: SPI communication clock
*SDIN: SPI communication master sends, slave receives
*Timing: CPHL=0, CPOL=0 (SPI0)
[Remarks] For specific information about SPI, you can search for information online.<big>
==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 display 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.
|heading = Working with the STM32
('''Note that the e-Paper cannot support updating directly under sunlight''')
|content = User guides for the development demo based on STM32CubeMX}}
===Pixel & Byte===
We define the pixels in a monochrome picture, 0 is black and 1 is white.<br />
White:□: Bit 1<br />
Black:■: Bit 0<br />
*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<br />
*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:<br />
[[file:e-paper_hardware_work_1.png]]<br />
For computer, the data is saved in MSB format:<br />
[[file:e-paper_hardware_work_2.png]]<br />
|heading = Working with ESP32/8266
So we can use two bytes for 16 pixels.<br />
|content = User guides for ESP32/8266}}
*4.2inch e-paper's 4-level display (black and white 2-level display is still the same as above)<br />
First of all, we need to understand the 4 grayscale picture, which shows that the brightness change between the brightest and the darkest is divided into 4 parts, from white to black, with 2 more colors in the middle, we can define it as light gray, dark Ash. <br />
|heading = Resources
Black: 00b<br />
|content = Documentation, procedures and data sheets, etc}}
Dark Grey: 01b<br />
Light Gray: 10b<br />
White: 11b<br />
In order to save storage space in general computers, four grays generally occupy 2 bytes. In the above example, taking 8 pixels as an example, 2 pixels are black, 2 pixels are dark gray, 2 pixels are light gray, and 2 pixels are White: <br />
[[file:Pixel.png]]<br />
The same 4 grayscale picture can be regarded as the superposition of 2 pictures. The same pixel of different pictures is superimposed to form a pixel. There are 4 combinations of this point, that is, 4 grayscales:<br />
{|border=1; style="width:700px;"
|-style="background:#0000ff; color:white;" align="center"
|Register||White||Light Gray||Dark Gray||Black
|}<br />
The relationship between the 4 grayscales and the memory has been known above, and it is known that the color of the ink screen is inconsistent with different combinations, so the above data needs to be converted:<br />
[[File:E-paper hardware work 9.png]]
#For the screen that supports partial update, please note that you cannot refresh the screen with the partial mode all the time. After several partial updating, you need to fully refresh the screen once. Otherwise, the screen display effect will be abnormal, which cannot be repaired!<br/>
|heading = FAQ
#Because of the different batches, some of them have aberrations. Store the e-Paper right side up will reduce it. And if the e-Paper didn't be refreshed for a long time, it will become more and more reddish/yellowish. Please use the demo code to refresh the e-paper several times in this case.<br/>
|content = e-Paper frequently asked questions}}
#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 the e-Paper. Otherwise, the screen will remain in a high voltage state for a long time, which will damage the e-Paper and cannot be repaired!<br/>
#When using the e-Paper, it is recommended that the refresh interval be at least 180s, and refresh at least once every 24 hours. If the e-Paper is not used for a long time, the ink screen should be brushed and stored. (Refer to the datasheet for specific storage environment requirements)<br/>
#After the screen enters sleep mode, the sent image data will be ignored, and it can be refreshed normally only after initializing again.<br/>
#Control the 0x3C or 0x50 (refer to the datasheet for details) register to adjust the border color. In the routine, you can adjust the Border Waveform Control register or VCOM AND DATA INTERVAL SETTING to set the border.<br/>
#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.<br/>
#The working voltage of the e-Paper 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 working environments. The old version can only support 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)<br/>
#The FPC cable of the screen is relatively fragile, pay attention to bending the cable along the horizontal direction of the screen when using it, and do not bend the cable along the vertical direction of the screen<br/>
#The screen of e-Paper is relatively fragile, please try to avoid dropping, bumping, and pressing hard.<br/>
#We recommend that customers use the sample program provided by us to test with the corresponding development board after they get the screen.<br/>
<div class="tabbertab" title="User Guides of Pi">
{{Raspberry Pi Guides for SPI e-Paper}}
|heading = Support
<div class="tabbertab" title="User Guides of Jetson Nano">
|content = Technical support
{{Jetson Nano Guides for SPI e-Paper}}
<div class="tabbertab" title="User Guides of STM32">
{{STM32 Guides for SPI e-Paper}}
<div class="tabbertab" title="User Guides of Arduino">
{{Arduino Guides for SPI e-Paper}}
<div class="tabbertab" title="User Guides of ESP32">
{{ESP32 Guides for SPI e-Paper}}
<div class="tabbertab" title="User Guides of ESP8266">
{{ESP8266 Guides for SPI e-Paper}}
=== Display a Frame (DisplayFrame) ===
DisplayFrame is used to send a frame to module, and the screen will refresh and display it.
Process: resolution setting -> VCM DC setting -> VCOM and data interval setting -> Send command data start transmission 1 -> Send data of an white image (send 0xFF 15000 times) -> Send command data start transmission 2 -> Send data of an image to display -> set LUT -> Refresh the screen.
* You have to send a white frame before the frame to display.
* 1 byte = 8 pixels, doesn’t support Gray scale (Can only display black and white). A bit set stands for a white pixel, otherwise a bit reset stands for black.
For example:
0xC3:8 pixels □□■■■■□□
0x00:8 pixels ■■■■■■■■
0xFF:8 pixels □□□□□□□□
0x66:8 pixels ■□□■■□□■
* This module doesn’t support partial refresh.
* The refresh rate of this module is slow, and it will flicker for several times during refreshing. Please be patient.
<div class="tabbertab" title="Resources">
*[ User Manual]
{{Commom Instruction of SPI e-paper}}
* [[:File:4.2inch_e-Paper_Schematic.pdf|Schematic]]
==Demo code==
*[ Github]
*[ UC8176 (controller) datasheet]
==Related Resources==
Notice:<br />
The projects listed are all made and shared by the project owners, Waveshare isn't responsible for project either the update.<br />
*[ Waveshare e-Paper display with SPI]
:This is a post in Arduino Form about our SPI e-Paper thanks to ZinggJM, maybe you want to refer to.
*[ Inkycal Project]
:This is the Inkycal project for reference.
<div class="tabbertab" title="FAQ">
{{e-paper Hat FAQ}}

Latest revision as of 06:25, 24 March 2023

4.2inch e-Paper Module Manual

E-Paper Introduction 4.jpg


Parameters, principles and precautions
Rapberry Pi.jpg

Working with Raspberry Pi

User guides for the development demo of C language, Python

Working with the Arduino

User guides for the development demo based on Arduino UNO R3
Jetson Arduino00.jpg

Working with the Jetson Nano

User guides for the development demo of C language, Python
Sunrise X3 Pi.jpg

Working with Sunrise X3 Pi

User guides for the development demo based on Python

Working with the STM32

User guides for the development demo based on STM32CubeMX
E-Paper ESP32.jpg

Working with ESP32/8266

User guides for ESP32/8266


Documentation, procedures and data sheets, etc


e-Paper frequently asked questions


Technical support