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WSAL20345 – Pico-ePaper-4.2-B/en

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Documentation notice: This technical documentation was independently rewritten from an archived supplier source. Check technical details and commands against the product version and manufacturer documentation before use.

Summary

The Pico e-Paper 4.2 B is a 4.2-inch e-ink display module for the Raspberry Pi Pico with a 400×300 resolution and red/black/white colors. It is driven via an SPI interface and requires minimal GPIOs.

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Technical overview

  • Resolution: 400 × 300 pixels; screen diagonal 4.2 inches.
  • Display colors: red, black, white; greyscale levels: 2.
  • SPI timing: CPHL=0, CPOL=0 (mode 0); CS active-low; DC=0 writes command, DC=1 writes data.
  • Pico pinout: VCC→VSYS, GND→GND, DIN→GP11 (MOSI), CLK→GP10 (SCK), CS→GP9, DC→GP8, RST→GP12, BUSY→GP13.
  • Pixel definition: 1 bit per pixel; 1 byte drives 8 pixels. For tri-color displays, two image data streams are used: one black/white image and one red/white image, each 1 byte per 8 pixels.
  • Full refresh takes about 15 s; refreshing power typical 38.4 mW; sleep current < 0.01 µA.
  • No backlight required; the display reflects ambient light and retains the last image after power-down.
  • Two user buttons on the module enable simple interaction.
  • Example files are provided as C and Python examples; the C examples require modifying main.c according to the specific model.
  • Flashing firmware: hold BOOTSEL, connect USB, copy UF2 file; for MicroPython use the matching .uf2 for Pico or Pico 2.

Commands and examples – verify before use:  

cd ~
sudo wget https://files.waveshare.com/upload/5/5a/Pico_ePaper_Code.zip
unzip Pico_ePaper_Code.zip -d Pico_ePaper_Code
cd ~/Pico_ePaper_Code
git clone https://github.com/waveshare/Pico_ePaper_Code.git
cd ~/Pico_ePaper_Code/c
mkdir build
cd build
export PICO_SDK_PATH=../../pico-sdk
cmake -DPICO_BOARD=pico -DPICO_PLATFORM=rp2040 ..
make -j9
cp epd.uf2 /media/pi/RPI-RP2/

Notes and version constraints

  • The stated refresh time (~15 s) and power figures are experimental measurements; actual values may vary by environment.
  • Global refresh causes flicker – this is normal for e-ink displays.
  • Example files contain multiple variants; the line for the specific model must be uncommented in main.c.
  • Flashing requires holding the BOOTSEL button during USB connection; the correct UF2 file depends on the Pico type (Pico vs. Pico 2).
  • The waveform file (.wbf) must match the specific display; a mismatched file results in no or inaccurate display.
  • E-ink under direct sunlight may not update reliably; ambient light conditions affect the result.

Source and revision record

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