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Freigegebene technische Dokumentation veröffentlicht; Text-only und noindex

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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.

== Related products at JW Tech ==
* [https://shop.jw-tech.eu/p/WSAL20345 WSAL20345 – 4.2inch E-Paper E-Ink Display Module (B) for Raspberry Pi Pico, 400×300, Red / Black / White, SPI]

== 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:'''
<syntaxhighlight lang="text">
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/
</syntaxhighlight>

== 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 ==
* [https://www.waveshare.com/wiki/Pico-ePaper-4.2-B Pico e-Paper 4.2 B - Waveshare Wiki]
* Source revision: 98700
* Captured: 2026-09-02T03:45:26+00:00
* SHA-256: <code>e8a09a687549ab85a91fe20f32ee755873dbb215d0b7d6c25c0fd70a5708c505</code>

WSAL20345 – Pico-ePaper-4.2-B/en - Versionsgeschichte

JWTechPublisher: Freigegebene technische Dokumentation veröffentlicht; Text-only und noindex