13.3inch e-Paper HAT
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Overview
Introduction
- 13.3-inch EPD (Electronic Paper Display) HAT for Raspberry Pi, 1600 × 1200 resolution, 16 grayscales, USB/SPI/I80/I2C interface.
- It has the advantages of low power consumption, wide viewing angle, and clear display under direct sunlight, and is often used in display applications such as shelf labels and industrial instruments.
- 13.3inch e-Paper is a big size screen, the glass panel, and FPC is fragile, please be careful when using it for development. we recommend you reinforce the FPC with scotch tape when developing. Please connect all the cables before powering the device, the device cannot support a hot plug.
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Features
- No backlight, keeps displaying the last content for a long time even when power is off.
- Low power consumption, basically power is only required for refreshing.
- Compatible with Raspberry Pi Zero/Zero W/Zero WH/2B/3B/3B+.
- USB/SPI/I80/I2C interface, for connecting with host boards like Raspberry Pi/Nucleo, etc.
- Comes with development resources and manual (examples for Raspberry Pi/STM32).
Specifications
- Operating voltage: 5V
- Interface: USB/SPI/I80
- Outline dimension: 285.80mm × 213.65mm × 0.78mm
- Display size: 270.40 × 202.80mm
- Dot pitch: 0.169 × 0.169mm
- Resolution: 1600 × 1200 pixels
- Display color: black, white
- Grayscale: 2-16 (1-4 bit)
- Full refresh time: <1s
- Total refresh power: 1.2W (typ.)
- Total standby power: 0.1W (typ.)
- Viewing angle: >170°
Working principle
This product is an E-paper device adopting the image display technology of Microencapsulated Electrophoretic Display, MED. The basic principle is that charged nanoparticles suspended in a liquid migrate under the action of an electric field. 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. (Note that the e-Paper cannot support updating directly under sunlight.)
How to use
Working with Windows PC
- Connect the display to IT8951 driver board as below:
- Connect the USB interface of the IT8951 driver board to PC.
- Download and open E-LINK-TCON-DEMO software.
- Click connect as below.
- Check option "AutoSet", then click "Open File" to open one picture for display. The browse diagram will be opened, and you should click "OK".
- Click "display" to refresh the picture.
Note: If you want to use the USB interface to develop the e-Paper on Windows, you need to contact the Waveshare team and sign the NDA before you can get the E-LINK-TCON-DEMO source code.
Note: Currently not available for individual users.
Working with Raspberry Pi
- Step1: Hardware connection
- Insert IT8951 driver board to GPIO of Raspberry Pi, Connect e-Paper to the driver board.
- You can also connect by wires.
| IT8951 Driver HAT | Raspberry Pi (BCM) | Description |
| 5V | 5V | 5V power input |
| GND | GND | Ground |
| MISO | P9 | MISO Pin of SPI |
| MOSI | P10 | MOSI Pin of SPI |
| SCK | P11 | SCK Pin of SPI |
| CS | P8 | Chip selection of SPI (Low active) |
| RST | P17 | Reset pin (Low active) |
| HRDY | P24 | Busy stats pin (Low when busy) |
- Step 2: Make sure you have switched the sail switch to SPI mode.
- Step3: Download and install BCM2835 libraries to your Raspberry Pi.
- You can also download the newest bcm2835 library from its official website http://www.airspayce.com/mikem/bcm2835/
- Copy the library you download to Raspberry Pi and install it with the commands below. You can also follow the instruction on its website above.
wget http://www.airspayce.com/mikem/bcm2835/bcm2835-1.60.tar.gz tar zxvf bcm2835-1.60.tar.gz cd bcm2835-1.60/ ./configure make sudo make check sudo make install
- Step4: Enable SPI Interface of Pi
- Open a terminal and type the following command:
sudo raspi-config
- Choose Interface Option->SPI->Yes
- Step5: Download Demo codes of 10.3inch e-Paper HAT and test
Method 1: Download from our official website(recommended)
sudo apt-get install p7zip-full sudo wget https://files.waveshare.com/upload/8/80/IT8951_20200319_Release.7z 7z x IT8951_20200319_Release.7z -O./IT8951 cd IT8951/ sudo make clean sudo make
Method 2: Download from GitHub.
git clone https://github.com/waveshare/IT8951-ePaper.git cd IT8951-ePaper/Raspberry sudo make clean sudo make -j4
Check the VCOM value on the FPC.
Add the VCOM value as a parameter and test the e-Paper, and this model is mode 0.
sudo ./epd -2.51 0
- Demo execution phenomenon:
1) First, the r-paper will refresh the 16 gray bars partially in sequence.
2) Then demonstrate the demo of drawing lines, circles, rectangles, characters, and numbers.
3) Then respectively demonstrate the demo of displaying bmp pictures in 1bp, 2bp, and 4bp modes.
4) Next, demonstrate the effect of fast refresh in A2 mode.
5) Then display a gif animation.
6) Then demonstrate a Demo that counts the frame rate.
7) Finally, the e-paper is whitened in Init mode for long-term storage.
Working with STM32
As IT8951 will occupy a lot of RAM, some of STM32 cannot support without an external SDRAM device. So we here use Open429I as a test board, Open429I integrates IS42S16400J (64-MBIT) SDRAM and has full memory to drive the 9.7inch e-paper.
Working with STM32, you can use SPI, I80, or I2C interface. SPI is simple and only a few of GPIOs are used, its speed can also meet the requirement of most applications. I80 is also simple and fast, however, it needs to use lots of GPIO. I2C is very slow, which we don't recommend.
SPI
1) Hardware connection
| IT8951 | STM32 | Description |
| 5V | 5V | 5V Power input |
| GND | GND | Ground |
| MISO | PE13 | Data output |
| MOSI | PE14 | Data input |
| SCK | PE12 | Clock input |
| CS | PE11 | Chip select (Low active) |
| RST | PC5 | Reset (Low for reset) |
| HRDY | PA7 | BUSY state output (Low for busy) |
2) Set the DIP switch to SPI mode
3) Download the demo code and test
You can download the Demo code.
Open the project with keil: Open429I-C-6-IT8951-Demo\Project\6-IT8951\MDK-ARM\Project.uvproj.
Compile it, then open IT8951.h, and check if SPI mode is enabled. Compile it again and download it to your board.
After downloading, the information will be printed as below (115200, 8N1).
I80
1） Hardware connection
| IT8951 | STM32 | Description |
| VCC | 5V | 5V Power input |
| GND | GND | Ground |
| DBUS0~DBUS15 | PB0~PB15 | Data pins |
| HWE | PC1 | Write enable (Low active) |
| D/C | PC7 | Data/Command (Low for command) |
| CSEL | PC6 | Chip select (Low active) |
| HRD | PC3 | Read enable (Low for active) |
| RST | PC0 | Reset (Low for reset) |
| BUSY | PA7 | Busy state output (Low for busy) |
2) Set the DIP switch to I80 mode.
3) Display with demo code.
You can download the Demo code.
Open the project with keil: Open429I-C-6-IT8951-Demo\Project\6-IT8951\MDK-ARM\Project.uvproj.
Compile it, then open IT8951.h, and check if I80 mode is enabled. Compile it again and download it to your board.
Information is printed to the serial port as below (115200, 8N1).
Display pictures
For easy porting of our demo code, we display pictures with a data matrix instead of the file system.
We should first convert the BMP picture to a data matrix (arrays), and use it in the demo code.
1) Prepare a BMP image, and resize the picture to 800*600.
2) Open BMP convert software, Click File -> Open.. -> to open the picture as below:
3) Click Image -> Convert to -> Gray256(8 BPP).
4) Click File -> Save As... -> Choose "C" bitmap file (*.c) -> input file name and click Save.
5) Choose 8 bits per pixel, and click OK. A C file will be saved to your PC.
6) Add the C file to the keil project and delete unusable information.
*********************************************************************
* SEGGER Microcontroller GmbH & Co. KG *
* Solutions for real time microcontroller applications *
* www.segger.com *
**********************************************************************
* *
* C-file generated by *
* *
* Bitmap Converter for emWin V5.22. *
* Compiled Jul 4 2013, 12:18:24 *
* (c) 1998 - 2013 Segger Microcontroller GmbH && Co. KG *
* *
**********************************************************************
* *
* Source file: zoo_800_600 *
* Dimensions: 800 * 600 *
* NumColors: 256 *
* *
**********************************************************************
*/
#include <stdlib.h>
#include "GUI.h"
#ifndef GUI_CONST_STORAGE
#define GUI_CONST_STORAGE const
#endif
extern GUI_CONST_STORAGE GUI_BITMAP bmzoo_800_600;
/*********************************************************************
*
* Palette
*
* Description
* The following are the entries of the palette table.
* The entries are stored as a 32-bit values of which 24 bits are
* actually used according to the following bit mask: 0xBBGGRR
*
* The lower 8 bits represent the Red component.
* The middle 8 bits represent the Green component.
* The highest 8 bits represent the Blue component.
*/
static GUI_CONST_STORAGE GUI_COLOR _Colorszoo_800_600[] = {
0x000000, 0x010101, 0x020202, 0x030303,
0x040404, 0x050505, 0x060606, 0x070707,
0x080808, 0x090909, 0x0A0A0A, 0x0B0B0B,
0x0C0C0C, 0x0D0D0D, 0x0E0E0E, 0x0F0F0F,
0x101010, 0x111111, 0x121212, 0x131313,
0x141414, 0x151515, 0x161616, 0x171717,
0x181818, 0x191919, 0x1A1A1A, 0x1B1B1B,
0x1C1C1C, 0x1D1D1D, 0x1E1E1E, 0x1F1F1F,
0x202020, 0x212121, 0x222222, 0x232323,
0x242424, 0x252525, 0x262626, 0x272727,
0x282828, 0x292929, 0x2A2A2A, 0x2B2B2B,
0x2C2C2C, 0x2D2D2D, 0x2E2E2E, 0x2F2F2F,
0x303030, 0x313131, 0x323232, 0x333333,
0x343434, 0x353535, 0x363636, 0x373737,
0x383838, 0x393939, 0x3A3A3A, 0x3B3B3B,
0x3C3C3C, 0x3D3D3D, 0x3E3E3E, 0x3F3F3F,
0x404040, 0x414141, 0x424242, 0x434343,
0x444444, 0x454545, 0x464646, 0x474747,
0x484848, 0x494949, 0x4A4A4A, 0x4B4B4B,
0x4C4C4C, 0x4D4D4D, 0x4E4E4E, 0x4F4F4F,
0x505050, 0x515151, 0x525252, 0x535353,
0x545454, 0x555555, 0x565656, 0x575757,
0x585858, 0x595959, 0x5A5A5A, 0x5B5B5B,
0x5C5C5C, 0x5D5D5D, 0x5E5E5E, 0x5F5F5F,
0x606060, 0x616161, 0x626262, 0x636363,
0x646464, 0x656565, 0x666666, 0x676767,
0x686868, 0x696969, 0x6A6A6A, 0x6B6B6B,
0x6C6C6C, 0x6D6D6D, 0x6E6E6E, 0x6F6F6F,
0x707070, 0x717171, 0x727272, 0x737373,
0x747474, 0x757575, 0x767676, 0x777777,
0x787878, 0x797979, 0x7A7A7A, 0x7B7B7B,
0x7C7C7C, 0x7D7D7D, 0x7E7E7E, 0x7F7F7F,
0x808080, 0x818181, 0x828282, 0x838383,
0x848484, 0x858585, 0x868686, 0x878787,
0x888888, 0x898989, 0x8A8A8A, 0x8B8B8B,
0x8C8C8C, 0x8D8D8D, 0x8E8E8E, 0x8F8F8F,
0x909090, 0x919191, 0x929292, 0x939393,
0x949494, 0x959595, 0x969696, 0x979797,
0x989898, 0x999999, 0x9A9A9A, 0x9B9B9B,
0x9C9C9C, 0x9D9D9D, 0x9E9E9E, 0x9F9F9F,
0xA0A0A0, 0xA1A1A1, 0xA2A2A2, 0xA3A3A3,
0xA4A4A4, 0xA5A5A5, 0xA6A6A6, 0xA7A7A7,
0xA8A8A8, 0xA9A9A9, 0xAAAAAA, 0xABABAB,
0xACACAC, 0xADADAD, 0xAEAEAE, 0xAFAFAF,
0xB0B0B0, 0xB1B1B1, 0xB2B2B2, 0xB3B3B3,
0xB4B4B4, 0xB5B5B5, 0xB6B6B6, 0xB7B7B7,
0xB8B8B8, 0xB9B9B9, 0xBABABA, 0xBBBBBB,
0xBCBCBC, 0xBDBDBD, 0xBEBEBE, 0xBFBFBF,
0xC0C0C0, 0xC1C1C1, 0xC2C2C2, 0xC3C3C3,
0xC4C4C4, 0xC5C5C5, 0xC6C6C6, 0xC7C7C7,
0xC8C8C8, 0xC9C9C9, 0xCACACA, 0xCBCBCB,
0xCCCCCC, 0xCDCDCD, 0xCECECE, 0xCFCFCF,
0xD0D0D0, 0xD1D1D1, 0xD2D2D2, 0xD3D3D3,
0xD4D4D4, 0xD5D5D5, 0xD6D6D6, 0xD7D7D7,
0xD8D8D8, 0xD9D9D9, 0xDADADA, 0xDBDBDB,
0xDCDCDC, 0xDDDDDD, 0xDEDEDE, 0xDFDFDF,
0xE0E0E0, 0xE1E1E1, 0xE2E2E2, 0xE3E3E3,
0xE4E4E4, 0xE5E5E5, 0xE6E6E6, 0xE7E7E7,
0xE8E8E8, 0xE9E9E9, 0xEAEAEA, 0xEBEBEB,
0xECECEC, 0xEDEDED, 0xEEEEEE, 0xEFEFEF,
0xF0F0F0, 0xF1F1F1, 0xF2F2F2, 0xF3F3F3,
0xF4F4F4, 0xF5F5F5, 0xF6F6F6, 0xF7F7F7,
0xF8F8F8, 0xF9F9F9, 0xFAFAFA, 0xFBFBFB,
0xFCFCFC, 0xFDFDFD, 0xFEFEFE, 0xFFFFFF
};
static GUI_CONST_STORAGE GUI_LOGPALETTE _Palzoo_800_600 = {
256, // Number of entries
0, // No transparency
&_Colorszoo_800_600[0]
};
GUI_CONST_STORAGE GUI_BITMAP bmzoo_800_600 = {
800, // xSize
600, // ySize
800, // BytesPerLine
8, // BitsPerPixel
_aczoo_800_600, // Pointer to picture data (indices)
&_Palzoo_800_600 // Pointer to palette
};
7) Modify the codes
static GUI_CONST_STORAGE unsigned char _aczoo_800_600[] = {
to this one. (You can change the name of the array as you like.)
const unsigned char zoo_800_600[] = {
8) Modify related codes in IT8951.C as below:
extern const unsigned char zoo_800_600[];
void IT8951DisplayExample3()
{
IT8951LdImgInfo stLdImgInfo;
IT8951AreaImgInfo stAreaImgInfo;
TWord width = gstI80DevInfo.usPanelW;
TWord high = gstI80DevInfo.usPanelH;
TDWord i;
for (i = 0;i < width*high;i++)
{
gpFrameBuf[i] = zoo_800_600[i];
}
IT8951WaitForDisplayReady();
//Setting Load image information
stLdImgInfo.ulStartFBAddr = (TDWord)gpFrameBuf;
stLdImgInfo.usEndianType = IT8951_LDIMG_L_ENDIAN;
stLdImgInfo.usPixelFormat = IT8951_8BPP;
stLdImgInfo.usRotate = IT8951_ROTATE_0;
stLdImgInfo.ulImgBufBaseAddr = gulImgBufAddr;
//Set Load Area
stAreaImgInfo.usX = 0;
stAreaImgInfo.usY = 0;
stAreaImgInfo.usWidth = width;
stAreaImgInfo.usHeight = high;
IT8951HostAreaPackedPixelWrite(&stLdImgInfo, &stAreaImgInfo);//Display function 2
IT8951DisplayArea(0,0, gstI80DevInfo.usPanelW, gstI80DevInfo.usPanelH, 2);
}
【Note】Guides provided here is all about how to use the 13.3inch e-Paper HAT (D). If you have any questions about how to modify and develop your own codes, please refer to resources of IT8951 #Resources.
Note
Hardware connection
For different e-paper screen models, due to the product upgrades and improvements, there may be some differences in hardware connection compared with the picture. So please directly refer to the FPC line pin number:
- Check example 1:
- Check example 2:
DIP switch
- We currently don't recommend using the I2C interface for the driver, it is recommended to use a USB, I80, or SPI interface.
- Whether you are using a USB interface driver, I80 interface driver, or SPI interface driver, you need to turn the DIP switch(marked in the red frame in the picture below) to the ON position on the right, as shown in the picture below:
- If you use USB to connect the driver board to the PC when the E-LINK-TCON-DEMO cannot recognize IT8951, please check whether the two DIP switches marked in the red frame are connected. Only the two DIP switches marked are both connected, and the driver board can be recognized by the PC.
SPI or I80 driver
- If you use a USB driver, you don’t need to pay attention to the DIP switch in the green frame as shown in the picture below.
- If you want to use the SPI driver or the I80 driver, you need to pay attention to the dial switch in the green frame as shown in the picture below. If it is dialed to the I80 side, it means using the I80 driver, if it is dialed to the SPI side, it means using the SPI driver:
Precaution
Hardware Connection
For different ink screen models, due to product upgrades and improvements, there may be certain differences between the hardware connection and the picture, and the specific FPC line pin label shall prevail:
Check example 1:
Check example 2:
DIP switch
I2C interface driver is not recommended at present, it is recommended to use a USB, I80, or SPI interface.
Whether it is driven by a USB interface, I80 interface, or SPI interface, it is necessary to turn the DIP switch circled in the red frame in the figure below to the ON position on the right, as shown in the figure below:
If the PC is connected by USB, and the E-LINK-TCON-DEMO cannot recognize the IT8951, please check whether both sides of the two DIP switches marked in the red frame are connected. Only the two DIP switches marked in the red frame are both connected. turn on to be recognized by the PC.
Choose SPI or I80 driver
If you use a USB drive, you don't need to pay attention to the DIP switch in the green frame shown in the figure below.
If you use SPI driver or I80 driver, you need to pay attention to the DIP switch in the green frame shown in the figure below. If it is dialed to the I80 terminal, it means that the I80 driver is used, and if it is dialed to the SPI terminal, it means that the SPI driver is used:
Codes Description
New Features
1. Update 16 grayscale images in 4bpp mode to reduce the data size while transmitting via SPI.
2. Double SPI transmitting speed. Note that this feature can only be valid in Raspberry Pi, it is invalid in Pi 4 because of the improvement of CPU.
3. Reduce the update time to 1/4. The last version of Demo codes cost 10s to update a picture on 10.3inch e-Paper (D) in GC16 Mode, with the new version, it is reduced to 3s.
4. Fix the bug that the memory leaks problem occurs after opening a BMP file.
5. Add 1bpp, 2bpp, 3bpp, and 4bpp modes support.
6. Add A2 Mode (only work for 1bpp mode).
7. Add GUI functions (Draw point, line, circle, rectangle, and string display). Supports changing gray.
8. Add 1bpp, 2bpp, 4bpp, and 8bpp refresh support for BMP pictures, if you choose 1bpp, it also supports A2 mode refresh.
9. Add a demo for displaying GIF pictures, which can write multiple pictures into the IT8951 cache, and directly swipe the data of different addresses in the cache into the ink screen for display, eliminating the data transmission process between RPi and IT8951, Refresh frame rate up to 7fps.
10. Add fps testing, it can be used to test the fps when updated with different windows sizes in different modes.
11. Enhance the driver, to fix the bug of blurred display in the partial area.
12. Support bytes alignment for 6inch ePaper HAT and 6inch HD ePaper HAT in 1bpp mode.
13. Add VCOM setting and clear ePaper function (running Demo codes directly) to protect ePaper from damage.
14. Improving the structure of driver codes for higher code readability.
Examples Description
Display 16 bars in grayscale order
- Function：Display ColorPalette Example
- This function is sued to display 16 bars in different grayscale. It uses 4bpp in GC16 mode.
Drawing
- Function： Display CharacterPattern Example
- This function is sued to draw points, lines, circles, and rectangles as well as display strings. It suppots 1bpp, 2bpp, 4bpp and 8bpp mode. If you use 1bpp, it can also support the A2 update mode.
Display BMP image
- Function：Display BMP Example
- This function is used to display a BMP image. It suppots 1bpp, 2bpp, 4bpp and 8bpp mode. If you use 1bpp, it can also support the A2 update mode.
Update ePaper in A2 mode
- Function：Dynamic Refresh Example
- This function is used to update ePaper in A2 Mode.
Display GIF image
- Function：Dynamic GIF Example
- This function is used to display GIF images. We divide a GIF file into seven BMP images and save them to a buffer of IT8951 with the continuous address. This demo features the fastest fps of the ePaper (about 7 fps).
FPS Testing
- Function：Check FrameRate Example
- This function is sued to test fps in different modes. The demo will auot-caculate the update time of 10 frames and the fps.
Related Description
Mode
The firmware in the IT8951 Driver board is different among different types of e-Paper. And the update mode may be different among these e-Paper. For more information about the update modes, you can refer to IT8951 Mode Description. There are three modes: INIT, GC16, and A2.
| Mode | Description | 6inch/6inch HD | 7.8inch/9.7inch/10.3inch |
|---|---|---|---|
| INIT | This mode is used for clearing the display. If you use A2 mode for updating, we recommend you use the INIT mode to clear display after updating several times. | Mode0 | Mode0 |
| GC16 | This mode is used for updating ePaper with 16 grayscale. GC16 mode can provide best dispaly effect. | Mode2 | Mode2 |
| A2 | A2 mode can only support 2 grayscale, however, the update speed is the fastest. | Mode4 | Mode6 |
//basic mode definition UBYTE INIT_Mode = 0; UBYTE GC16_Mode = 2; //A2_Mode's value is not fixed, is decided by the firmware's LUT UBYTE A2_Mode = 6;
if( strcmp(LUT_Version, "M641") == 0 ){
//6inch e-Paper HAT(800,600), 6inch HD e-Paper HAT(1448,1072), 6inch HD touch e-Paper HAT(1448,1072)
A2_Mode = 4;
Four_Byte_Align = true;
}else if( strcmp(LUT_Version, "M841") == 0 ){
//9.7inch e-Paper HAT(1200,825)
A2_Mode = 6;
}else if( strcmp(LUT_Version, "M841_TFA2812") == 0 ){
//7.8inch e-Paper HAT(1872,1404)
A2_Mode = 6;
}else if( strcmp(LUT_Version, "M841_TFA5210") == 0 ){
//10.3inch e-Paper HAT(1872,1404)
A2_Mode = 6;
}else{
//default set to 6 as A2 Mode
A2_Mode = 6;
}
bpp
bpp(Bits Per Pixel), stands for the bits costed by every pixel. The current versions of ePaper support 1bpp, 2bpp, 4bpp, and 8bpp modes.
- 1bpp
- 1bit cost by every pixel
- It supports 2 grayscale displays. supports A2 mode
- Evey byte carries 8 pixels
- The pixel is saved in byte in Big-endian format：
- The data is saved in IT8951 with Little-endian format, you need to convert the data before saving.
- 2bpp
- 2bits cost by every pixel
- Supports 4 (2^2=4) grayscale
- Evey byte carries 4 pixels
- The pixel is saved in byte in Big-endian format：
- The data is saved in IT8951 with Little-endian format, you need to convert the data before saving.
- 4bpp
- 4 bits cost by every pixel.
- Supports 16(2^4=16) grayscale
- Every byte carries 2 pixels
- The pixel is saved in byte in Big-endian format：
- The data is saved in IT8951 with Little-endian format, you need to convert the data before saving.
- 4bpp mode is recommended for displaying 16 grayscale images. It reduces half of the data by comparing to 8bpp.
- 8bpp
- 8bits cost by every pixel
- Supports 256 (2^8=256) grayscale. However, IT8951 only uses the first four bits for 16 grayscale displays.
- Every byte carries one pixel
- The pixel is saved in byte in Big-endian format：
- The data is saved in IT8951 with Little-endian format, you need to convert the data before saving.
- When you convert an original image for a gray image, the data of every pixel cost one byte (8 bits). You can compress the data according to the actual data format. For example: if you want to convert data for 2bpp mode, you can just use the first 2bits from one byte (original gray image). The examples below also convert the data format from big-endian to little-endian.
UDOUBLE Addr = X * (Paint.BitsPerPixel) / 8 + Y * Paint.WidthByte;
switch( Paint.BitsPerPixel ){
case 8:{
Paint.Image[Addr] = Color & 0xF0;
break;
}
case 4:{
Paint.Image[Addr] &= ~( (0xF0) >> (7 - (X*4+3)%8 ) );
Paint.Image[Addr] |= (Color & 0xF0) >> (7 - (X*4+3)%8 );
break;
}
case 2:{
Paint.Image[Addr] &= ~( (0xC0) >> (7 - (X*2+1)%8 ) );
Paint.Image[Addr] |= (Color & 0xC0) >> (7 - (X*2+1)%8 );
break;
}
case 1:{
Paint.Image[Addr] &= ~( (0x80) >> (7 - X%8) );
Paint.Image[Addr] |= (Color & 0x80) >> (7 - X%8);
break;
}
}
4-byte alignment description
In the actual test, we found that for those 3 products: 6inch e-Paper HAT, 6inch HD e-Paper HAT, and 6inch HD touch e-Paper HAT, when refreshing in 1bpp mode, we need to make the starting point of the refresh area X and the refresh width W to perform 4-byte (32bit) alignment, otherwise, the image in the refresh area will display abnormally. The specific operation is shown in the following demo:
if( strcmp(LUT_Version, "M641") == 0 ){
//6inch e-Paper HAT(800,600), 6inch HD e-Paper HAT(1448,1072), 6inch HD touch e-Paper HAT(1448,1072)
A2_Mode = 4;
Four_Byte_Align = true;
}else if( strcmp(LUT_Version, "M841") == 0 ){
...
}
if(Four_Byte_Align == true){
In_4bp_Refresh_Area_Width = Panel_Width - (Panel_Width % 32);
}else{
In_4bp_Refresh_Area_Width = Panel_Width;
}
X_Start = Min_X < 32 ? 0 : Min_X - (Min_X % 32);
Debug("X_Start:%d\r\n",X_Start);
X_End = ( Max_X + (32 - (Max_X % 32)) ) > Touch_Pannel_Area_Width ? ( Max_X - (Max_X % 32) ) : ( Max_X + (32 - (Max_X % 32)) );
Debug("X_End:%d\r\n",X_End);
Y_Start = Min_Y;
Debug("Y_Start:%d\r\n",Y_Start);
Y_End = Max_Y;
Debug("Y_Start:%d\r\n",Y_End);
Width = X_End - X_Start;
if(Width<=0){
Width = 32;
}
Debug("Width:%d\r\n",Width);
Height = Y_End-Y_Start;
if(Height<=0){
Height = 32;
}
Debug("Height:%d\r\n",Height);
SPI transmission speed description
Due to the difference in CPU frequency between Raspberry Pi 3 and Raspberry Pi 4:
- Raspberry Pi 3 can still transmit normally when the frequency is divided by 16, but the frequency by 16 is the fastest speed for Pi3.
- When the frequency of the Raspberry Pi 4B uses a divide by 16, the SPI rate is too high and transmission errors will occur. Therefore, the SPI of the Raspberry Pi 4B can only use a divide by 32 at the fastest.
- In the BCM2835 library manual, for different Raspberry Pi versions and different clock divisions, the corresponding frequency description is shown in the following figure:
- If you need to obtain the most suitable SPI transmission speed, you need to select a different SPI clock divider according to your Raspberry Pi version, as shown in the following program and its notes:
bcm2835_spi_begin();//Start spi interface, set spi pin for the reuse function bcm2835_spi_setBitOrder(BCM2835_SPI_BIT_ORDER_MSBFIRST);//High first transmission bcm2835_spi_setDataMode(BCM2835_SPI_MODE0);//spi mode 0 //bcm2835_spi_setClockDivider(BCM2835_SPI_CLOCK_DIVIDER_16);//For RPi 3/3B/3B+ bcm2835_spi_setClockDivider(BCM2835_SPI_CLOCK_DIVIDER_32);//For RPi 4B /* SPI clock reference link：*/ /*http://www.airspayce.com/mikem/bcm2835/group__constants.html#gaf2e0ca069b8caef24602a02e8a00884e*/
Enhance driving capability
In some cases, due to the long FPC cable and other reasons, the ink screen display will be partially blurred. In this case, you can try to increase the driving capability to effectively solve the problem of the screen display blur.
You can check the demo below:
#if(Enhance)
Debug("Attention! Enhanced driving ability, only used when the screen is blurred\r\n");
Enhance_Driving_Capability();
#endif
/******************************************************************************
function: Enhanced driving capability
parameter: Enhanced driving capability for IT8951, in case the blurred display effect
******************************************************************************/
void Enhance_Driving_Capability(void)
{
UWORD RegValue = EPD_IT8951_ReadReg(0x0038);
Debug("The reg value before writing is %x\r\n", RegValue);
EPD_IT8951_WriteReg(0x0038, 0x0602);
RegValue = EPD_IT8951_ReadReg(0x0038);
Debug("The reg value after writing is %x\r\n", RegValue);
}
If you use the E-LINK-TCON-DEMO software on a PC (Windows) to refresh the ink screen through the USB interface, you can modify the register value in the following ways to enhance the drive capability:
- Step1: Read the data of register address 0 x 18000038.
If the read data of register address 0 x 18000038 is 0 x 02, it means that the drive capability has not been enhanced yet.
- Step2: Modify the data of register address 0 x 18000038
Modify the data of register address 0 x 18000038 to 602 to enhance the driving capability.
- Step3: Check the data of register address 0 x 18000038.
Check whether the data of the registered address 0 x 18000038 is modified successfully. If the data of this address is 0 x 602, it means that the drive capacity has been enhanced.
Use the correct VCOM value
The VCOM value of each model of the e-paper is marked on the FPC cable. Make sure that you have used the correct VCOM value when you running the demo. Otherwise, the e-paper will deteriorate by working for a long time under the wrong VCOM value.
Resources
Schematic
Demo code
Datasheet
Other documents
Software
FAQ
Questions About Software & Hardware
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2. Try changing the USB interface. It is recommended to use the USB interface on the back of the PC. Relatively speaking, the power supply current will be larger.
3. Turn the DIP switch to the end. During shipping, the DIP switches may be loosened, and the floating configuration pins cannot put the IT8951 into USB mode.
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If you fail to refresh, check whether the hard link is normal, use the USB port on the back of the PC (most of the USB ports on the front of the PC have weak power supply capability), and replace the e-paper test.
Note: Do not plug and unplug the e-paper with power on, otherwise the driver board and e-paper may be damaged.
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Questions About Screen
- 【Operating condition】Temperature range: 0~50°C; Humidity range: 35%~65%RH
- 【Storage condition】Temperature range: below 30°C; Humidity range: below 55%RH; Maximum storage time: 6 months
- 【Transportation condition】Temperature range:-25~70°C; Maximum shipping time: 10 days
- 【After unpacking】Temperature range: 20°C±5°C; Humidity range: 50±5%RH; Maximum storage time: Assembled within 72 hours
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- Refresh mode:
- Full refresh: The e-ink screen will flicker several times during refreshing (the flicking times depends on the refresh time), and the flicker is to remove the ghosting to achieve the best display effect.
- Partial refresh: The e-ink screen has no flickering effect during refreshing. Users who use partial flashing should pay attention to performing a full flashing operation to remove the ghosting after refreshing several times, otherwise, the ghosting problem will become more and more serious, or even damage the screen. (At present, only some black and white e-ink screens support local brushing, please refer to the product page for details).
- Refresh frequency:
- During use, it is recommended that customers set the refresh interval of the e-ink screen to at least 180 seconds. (Except for products that support the partial refreshing function)
- During the standby process (that is, after the refresh operation), it is recommended that the customer set the e-ink screen to sleep mode, or power off (the power supply part of the ink screen can be disconnected with an analog switch) to reduce power consumption and prolong the life of the e-ink screen. (If some e-ink screens are powered on for a long time, the screen will be damaged beyond repair.)
- During the use of the e-ink screen, it is recommended that customers update the display screen at least every 24 hours. (If the screen keeps the same picture for a long time, there will be a burn-in situation that is difficult to repair).
- Application scenarios:
- The e-ink screen is recommended for indoor use. If it is used outdoors, it is necessary to prevent the e-ink screen from being exposed to direct sunlight, and at the same time, it is necessary to take ultraviolet 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 electronic ink screen products, customers should pay attention to determine whether the use environment meets the requirements of electronic ink screens.
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