Template: Pico e-Paper 2.9 B Spec

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2.9inch EPD (Electronic Paper Display) Module For Raspberry Pi Pico, 296 × 128 Pixels, Black / White / Red, SPI Interface.


  • Size: 2.9inch
  • Outline dimensions(raw panel): 79.0mm × 36.7mm × 1.05mm
  • Outline dimension(driver board): 82.0mm × 38.0mm
  • Display size: 66.89mm × 29.05mm
  • Operating voltage: 3.3V/5V
  • Interface: SPI
  • Dot pitch: 0.138 × 0.138
  • Resolution: 296 × 128
  • Display color: Black, White, Red
  • Greyscale: 2
  • full refresh time: 15s
  • Refresh power: 26.4mW (typ.)
  • Standby current: <0.01uA (almost none)
  • Note:

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.

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.

SPI Communication Timing


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.

  • CS: Slave chip select, when CS is low, the chip is enabled.
  • DC: data/command control pin, write command when DC=0; write data when DC=1.
  • SCLK: SPI communication clock.
  • SDIN: SPI communication master sends, the slave receives.
  • Timing: CPHL=0, CPOL=0 (SPI0)

【Remarks】For specific information about SPI, you can search for information online.

Working Protocol

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. (Note that the e-Paper cannot support updating directly under sunlight).

How to define pixels

In a monochrome picture we define the pixels, 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:

E-paper hardware work 1.png
For the computer, the data is saved in MSB format:
E-paper hardware work 2.png
So we can use two bytes for 16 pixels.

For 2.13inch e-paper B, the display colors are red, black, and white. We need to split the picture into 2 pictures, one is a black and white picture, and another is a red and white picture. When transmitting, because one register controls a black or white pixel, one controls a Red or white display. The black and white part of 2.13 use 1 byte to control 8 pixels, and the red and white part uses 1 byte to control 8 pixels.
For example, suppose there are 8 pixels, the first 4 are red, and the back 4 are black:
They need to be disassembled into a black and white picture and a red and white picture. Both pictures have 8 pixels, but the first four pixels of the black and white picture are white, the last 4 pixels are black, and the first 4 pixels of the red and white picture One pixel is red, and the last four pixels are white.


If you define that the data of the white pixel is 1 and the black is 0, then we can get:


So that we can use 1 byte to control every eight pixels.



  1. 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!
  2. 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.
  3. 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!
  4. 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)
  5. After the screen enters sleep mode, the sent image data will be ignored, and it can be refreshed normally only after initializing again.
  6. 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.
  7. 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.
  8. 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)
  9. 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
  10. The screen of e-Paper is relatively fragile, please try to avoid dropping, bumping, and pressing hard.
  11. We recommend that customers use the sample program provided by us to test with the corresponding development board after they get the screen.