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patriandClaude Opus 5.5 55e27b6572 Port display_gif_sd and display_speed_wifi to LVGL 9.6 + shared library

- both use shared/jc3636w518.ini, board library and perf monitor
- GIF decoded in the display color format, loop delay 1 ms,
  per-loop memory prints removed
- lv_conf: LVGL drive A: = SD card via LV_USE_FS_STDIO (/sdcard/)
- shared/README.md, CLAUDE.md and project README updated

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

2026-10-23 01:37:29 +02:00

3.3 KiB

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OBD Display (2024 experiments)

Earlier attempt to show car speed from an ELM327 OBD-II adapter on the JC3636W518. Because the ESP32-S3 has no Bluetooth Classic, the design used a second (classic) ESP32 as a bridge:

ELM327 --(BT Classic SPP)--> classic ESP32 (elm327_wifi_bridge) --(WiFi AP, HTTP /speed)--> JC3636W518 (display_speed_wifi)

Split out of 2-Program Example/Demo_Arduino/ST77916_LVGL_DEMO/ on 2026-10-22 and converted to PlatformIO. History is in git.

Projects (all PlatformIO)

Folder	Runs on	What it does	Was
`display_speed_wifi/`	JC3636W518	GIF background from SD (`A:wallpaper.gif`) + joins AP `ESP32-Access-Point`, polls `http://192.168.4.1/speed`, shows it in a label	`ST77916_LVGL_DEMO/8.4/`
`display_gif_sd/`	JC3636W518	GIF from SD (`A:wallpaper.gif`) + static text label	`ST77916_LVGL_DEMO/working version/`
`display_gif_embedded/`	JC3636W518	GIF compiled into firmware (`src/loligod.c`, 2.2 MB GIF → 3.4 MB firmware, uses `default_16MB.csv` with 6.25 MB app slots). LVGL 9.6.0, plays at full GIF speed (~23.4 fps), prints FPS once per second. GIF starts without SD card. WiFi code commented out.	`ST77916_LVGL_DEMO/` (top level)
`elm327_wifi_bridge/`	classic ESP32 (not S3)	BT Classic → ELM327 named `OBDII` (PIN 1234), WiFi AP `ESP32-Access-Point` / `123456789`, serves `/speed` (kph)	`ST77916_LVGL_DEMO/esp23_elm327_to_wifi/`
`elmulator/`	classic ESP32	Fake ELM327 for testing without a car. Library in `lib/ELMulator`, envs `simple`, `custom`, `wifi` (BT name `OBDII`)	`ST77916_LVGL_DEMO/ELMulator-master/`
`assets/gifs/`	—	GIF files (`dump/` = unused collection)	`ST77916_LVGL_DEMO/gifs/`
`_archive/lvgl9_broken/`	—	Unfinished LVGL 9 port, does not compile, not converted	`ST77916_LVGL_DEMO/9.1/`

Build / upload

Open a project folder in VS Code with the PlatformIO extension, or from a terminal:

pio run -d display_speed_wifi                 # build
pio run -d display_speed_wifi -t upload       # flash (COM21)
pio device monitor -d display_speed_wifi      # serial monitor
pio run -d elmulator -e wifi -t upload --upload-port COMxx

(pio = %USERPROFILE%\.platformio\penv\Scripts\pio.exe if not on PATH.)

Configuration

JC3636W518 projects (display_*): LVGL 9.6.0 and the shared board library/config in ../shared (see shared/README.md). Each platformio.ini only extends shared/jc3636w518.ini; display_gif_embedded additionally uses default_16MB.csv. All three print FPS / refresh / other / CPU once per second on serial (115200).
Classic ESP32 projects: official espressif32@6.10.0 (Arduino core 2.0.17), board esp32dev, huge_app.csv. Set upload_port to the classic ESP32's COM port. Bridge libraries: powerbroker2/ELMduino@3.4.1, esphome/ESPAsyncWebServer-esphome@3.4.0.

Notes

src/montserrat_100.c (100 px digits font) is present but not referenced by any sketch yet.
SD-based GIFs use LVGL drive A: = LV_USE_FS_STDIO on /sdcard/ (the SD_MMC mount). Not yet verified with LVGL 9 on hardware (SD card was stuck during the port).
display_speed_wifi polls /speed with a blocking HTTP request on every loop pass (unchanged from 2024) — slows the UI when WiFi is connected.

3.3 KiB Raw Blame History