tdeck-screenfix

Standalone screen-fixer firmware for the LILYGO T-Deck (ESP32-S3 / ST7789 2.8" IPS panel).

This is our own firmware — not a fork or derivative of MeshCore or any other firmware project. It is a minimal, self-contained PlatformIO project built around the official LilyGO T-Deck references (pin map, board definition) and a standard display driver library.

Keeps the display on 24/7 and cycles through image-retention / burn-in clearing patterns forever. Flash it, plug the T-Deck in, leave it running — no interaction needed.

Why

LCD panels can suffer from image retention (ghosting) when a static UI is left on screen for long periods. Cycling the panel through full-brightness solid colours, moving gradients, checkerboards and noise exercises every subpixel evenly and clears the retained image. The T-Deck's 2.8" ST7789 is no exception.

What it does

At boot the display lights up (backlight on GPIO 42, peripheral power rail on GPIO 10), all sleep sources are disabled (CPU locked at 240 MHz, no light sleep), and the routine starts. The ~4 minute cycle repeats forever:

#	Phase	Duration	What you see
1	Solid white	20 s	Full-screen white
2	Solid red	20 s	Full-screen red
3	Solid green	20 s	Full-screen green
4	Solid blue	20 s	Full-screen blue
5	Solid black	20 s	Panel off pixels (relax cycle)
6	Hue sweep	30 s	Scrolling rainbow gradient
7	Colour bars	20 s	Classic white/red/green/blue/cyan/magenta/yellow/black bars
8	Checkerboard	20 s	Black/white checkerboard, inverting every second
9	Sweep horizontal	30 s	White bar sweeping top → bottom
10	Sweep vertical	30 s	White bar sweeping left → right
11	Colour noise	20 s	Random-colour static

Progress is logged over USB serial (115200 baud): [screenfix] phase 3/11: solid green (20s) — uptime 64s.

All durations are compile-time configurable — see src/main.cpp PHASE_*_S defines.

Building

pio run                    # compile
pio run -t upload          # build + flash over USB (main USB-C port!)
pio device monitor         # watch phase progress

PlatformIO 6.x with the stock espressif32 platform is all you need — the T-Deck board definition is vendored in boards/t-deck.json, so the project builds out of the box with no extra setup.

Flashing

• Use the main USB-C port (ESP32-S3 native USB), not the keyboard one.
• Flash mode defaults to DIO in platformio.ini — many T-Deck units boot-loop with QIO flash (PSRAM pin conflict). If your unit runs QIO fine, remove that override.
• The merged binary lands at .pio/build/t-deck/firmware.bin — flash it with pio run -t upload or any ESP32 flasher.

Pin map (T-Deck)

From the official LilyGO T-Deck reference (TDECK_PINS.h):

Signal	GPIO
LCD CS	12
LCD DC	11
LCD backlight	42
LCD RST	not connected (software reset)
SPI SCK	40
SPI MOSI	41
Peripheral power rail	10

Attribution & licensing

• This project's code and docs (firmware, build config, README): MIT — see LICENSE.
• Board definition boards/t-deck.json: copied verbatim from the official Xinyuan-LilyGO/T-Deck repository (boards/T-Deck.json, © LilyGO).
• Pin map: from the official Xinyuan-LilyGO/T-Deck reference header examples/LvglArduinoVNC_VGA/TDECK_PINS.h (© LilyGO).
• Display driver: Adafruit ST7735 and ST7789 Library (+ Adafruit GFX / BusIO dependencies), BSD-3-Clause, © Adafruit Industries.

Full details in THIRD_PARTY_NOTICES.md.