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2.9" e-Paper Display

A high-contrast, ultra-low power electrophoretic display module that retains its image even when power is completely removed.

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SPI e-Paper

This 2.9-inch E-Ink / e-Paper display is famous for its paper-like readability in direct sunlight and its ability to hold an image indefinitely with zero power. It communicates via SPI.

DisplaysSPILow Power

Overview

Because of its unique physical properties, an e-Paper display does not emit light. Instead, it physically moves microscopic charged pigment particles to the surface. This means refreshing the screen is very slow (often taking a full second or two and flashing black/white to clear ghosting).

Pin Reference

Pin	Type	Description
VCC	power	Power supply (3.3V).
GND	power	Ground.
DIN	digital	SPI MOSI (Data In). Connect to Arduino D11.
CLK	digital	SPI Clock. Connect to Arduino D13.
CS	digital	Chip Select. Connect to Arduino D10.
DC	digital	Data/Command control. Connect to Arduino D9.
RST	digital	Reset pin. Connect to Arduino D8.
BUSY	digital	Busy status output. Connect to Arduino D7.

Configurable Attributes

This component has no configurable attributes.

Working Principle

When an update command is sent over SPI, the display controller drives specific voltages across a grid of tiny microcapsules. Black particles (negatively charged) and white particles (positively charged) move up or down depending on the field. Because the particles are physically suspended in a viscous fluid, they stay exactly where they are left when power is cut.

Wiring Diagram

Connect the e-Paper display to the Arduino via the SPI interface.

Example Arduino Code

Install the GxEPD2 library before running this example.

#include <SPI.h>
#include <GxEPD2_BW.h>

// Define pins
#define EPD_CS 10
#define EPD_DC 9
#define EPD_RST 8
#define EPD_BUSY 7

// Instantiate the display (using a common 2.9" profile)
GxEPD2_BW<GxEPD2_290_T94_V2, GxEPD2_290_T94_V2::HEIGHT> epd(GxEPD2_290_T94_V2(EPD_CS, EPD_DC, EPD_RST, EPD_BUSY));

void setup() {
  Serial.begin(9600);
  epd.init(115200);
  
  // Clear the screen
  epd.setFullWindow();
  epd.fillScreen(GxEPD_WHITE);
  
  // Draw text
  epd.setTextSize(2);
  epd.setTextColor(GxEPD_BLACK);
  epd.setCursor(20, 40);
  epd.println("Hello World!");
  
  // Push the buffer to the physical screen (this takes a moment)
  epd.display();
}

void loop() {
  // e-Paper doesn't need to be constantly refreshed!
  delay(10000);
}

Simulation Notes

• The simulator mimics the slow visual update process of an e-Paper display, including the characteristic screen flashing that occurs during a full refresh cycle.
• In the simulator, the display acts as a true SPI device.

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