ESP32-S3 + WeAct 2.13" E-Paper (ESP-IDF)

Test project for WeAct 2.13" black/white e-paper with ESP32-S3 using ESP-IDF.

The project includes:

• A reusable e-paper driver component (components/epaper_driver)
• SPI initialization for the display
• Simple framebuffer
• Simple text rendering (5x7 font) with scaling
• Full refresh of the e-paper panel
• Partial refresh API for region updates
• Wiring diagram in docs/epaper_wiring.svg

Hardware

• ESP32-S3
• WeAct 2.13" E-Paper (BW)
• 3.3V logic

Pinout (current)

ESP32-S3	E-Paper
GPIO6	DIN / SDA (MOSI)
GPIO4	CLK (SCK)
GPIO5	CS
GPIO1	DC
GPIO2	RST
GPIO3	BUSY
3V3	VCC
GND	GND

MISO is not used.

Build and flash

Run in the project folder:

source $IDF_PATH/export.sh
idf.py set-target esp32s3
idf.py build
idf.py flash monitor

Customization

Text size

Change in main/main.c:

• TEXT_SCALE (for example 2, 3, 4)

Text content

Change the strings in app_main() in main/main.c.

SPI speed and pins

Change driver config in main/main.c:

epaper_driver_config_t cfg = epaper_driver_default_config();
cfg.spi_hz = 4000000; // lower if needed
// cfg.pin_mosi, cfg.pin_clk, cfg.pin_cs, cfg.pin_dc, cfg.pin_rst, cfg.pin_busy
ESP_ERROR_CHECK(epaper_driver_init(&epaper, &cfg));

Reuse in other projects

Copy this component folder into another ESP-IDF project:

• components/epaper_driver/

Then include and use:

#include "epaper_driver.h"

epaper_driver_t epaper;
epaper_driver_config_t cfg = epaper_driver_default_config();
ESP_ERROR_CHECK(epaper_driver_init(&epaper, &cfg));

epaper_driver_clear(&epaper, true);
epaper_driver_draw_text_scaled(&epaper, 8, 10, "Hello", 3);
ESP_ERROR_CHECK(epaper_driver_update_full(&epaper));

And make sure your app component has:

idf_component_register(SRCS "main.c"
                    INCLUDE_DIRS "."
                    REQUIRES epaper_driver)

Partial refresh (region-based)

You can create a partial-refresh object for a region and update only that area:

epaper_partial_refresh_t part;
ESP_ERROR_CHECK(epaper_partial_refresh_init(&part, &epaper, 8, 10, 120, 40));

// Draw into the same framebuffer as usual
epaper_driver_draw_text_in_rect(
    &epaper,
    part.area.x, part.area.y, part.area.width, part.area.height,
    "Updated",
    2,
    true   // clear to white before drawing
);

// Refresh only the configured region
ESP_ERROR_CHECK(epaper_partial_refresh_update(&part));

Note: partial refresh now uses separate previous/current framebuffers internally. This avoids text corruption where partial updates could overwrite already visible content.

Available types/functions:

• epaper_rect_t
• epaper_partial_refresh_t
• epaper_driver_draw_text_in_rect(...)
• epaper_partial_refresh_init(...)
• epaper_partial_refresh_update(...)

Troubleshooting

Only half of the screen updates / dot pattern

The driver uses the panel's internal RAM format (122x250) and rotates coordinates in software. If the issue comes back, verify that these dimensions were not changed in components/epaper_driver/epaper_driver.c.

No update at all

• Verify BUSY/CS/DC/RST wiring
• Confirm 3.3V supply
• Try lower SPI speed (for example 2000000)

Image is upside down / wrong rotation

Rotation is handled in epaper_driver_draw_pixel() in components/epaper_driver/epaper_driver.c. You can adjust the mapping there for other panel revisions.

Partial refresh does not look correct

• Start with a full refresh (epaper_driver_update_full) after init
• Use epaper_driver_draw_text_in_rect(..., clear_white=true) for text replacement in a region
• Ensure the partial region covers all changed pixels
• If your panel revision behaves differently, tune update control in epaper_partial_refresh_update() in components/epaper_driver/epaper_driver.c

Files

• components/epaper_driver/include/epaper_driver.h - reusable public driver API
• components/epaper_driver/epaper_driver.c - reusable driver implementation
• components/epaper_driver/CMakeLists.txt - component registration
• main/main.c - demo app using the driver
• docs/epaper_wiring.svg - wiring diagram
• .gitignore - ESP-IDF/IDE ignore