patriandClaude Opus 5.5
9684ab39f2
- lvgl/lvgl@9.6.0 via lib_deps, lv_conf.h from the 9.6 template - scr_st77916.h: lv_display/lv_indev API, RGB565 byte swap in flush, lv_tick_set_cb - FPS counter via display refresh events - loligod.c: lv_image_dsc_t descriptor GIF now plays at its own frame rate; decode time halved by LVGL 9.6's AnimatedGIF decoder. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
45 lines
3.3 KiB
Markdown
45 lines
3.3 KiB
Markdown
# OBD Display (2024 experiments)
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Earlier attempt to show car speed from an ELM327 OBD-II adapter on the JC3636W518.
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Because the ESP32-S3 has no Bluetooth Classic, the design used a second (classic) ESP32 as a bridge:
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```
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ELM327 --(BT Classic SPP)--> classic ESP32 (elm327_wifi_bridge) --(WiFi AP, HTTP /speed)--> JC3636W518 (display_speed_wifi)
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```
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Split out of `2-Program Example/Demo_Arduino/ST77916_LVGL_DEMO/` on 2026-10-22 and converted to PlatformIO. History is in git.
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## Projects (all PlatformIO)
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| Folder | Runs on | What it does | Was |
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| `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/` |
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| `display_gif_sd/` | JC3636W518 | GIF from SD (`A:wallpaper.gif`) + static text label | `ST77916_LVGL_DEMO/working version/` |
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| `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) |
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| `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/` |
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| `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/` |
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| `assets/gifs/` | — | GIF files (`dump/` = unused collection) | `ST77916_LVGL_DEMO/gifs/` |
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| `_archive/lvgl9_broken/` | — | Unfinished LVGL 9 port, does not compile, not converted | `ST77916_LVGL_DEMO/9.1/` |
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## Build / upload
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Open a project folder in VS Code with the PlatformIO extension, or from a terminal:
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```
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pio run -d display_speed_wifi # build
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pio run -d display_speed_wifi -t upload # flash (COM21)
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pio device monitor -d display_speed_wifi # serial monitor
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pio run -d elmulator -e wifi -t upload --upload-port COMxx
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```
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(`pio` = `%USERPROFILE%\.platformio\penv\Scripts\pio.exe` if not on PATH.)
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## Configuration
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- **JC3636W518 projects:** pioarduino platform `51.03.05` (= Arduino core 3.0.5), board `esp32-s3-devkitc-1` with 16 MB QIO flash, OPI PSRAM, `huge_app.csv` (3 MB app), USB-CDC on boot, COM21.
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Libraries come from the vendor folder via `lib_extra_dirs = ../../2-Program Example/Demo_Arduino/library`.
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Each project uses its **own `include/lv_conf.h`** (`-DLV_CONF_INCLUDE_SIMPLE -Iinclude`):
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- `display_speed_wifi`: LVGL heap 4 MB in PSRAM (`ps_malloc`)
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- `display_gif_sd`: LVGL heap 7 MB in PSRAM
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- **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.
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Bridge libraries: `powerbroker2/ELMduino@3.4.1`, `esphome/ESPAsyncWebServer-esphome@3.4.0`.
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## Notes
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- `src/montserrat_100.c` (100 px digits font) is present but not referenced by any sketch yet.
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- SD-based GIFs use LVGL drive `A:` = `LV_USE_FS_FATFS` (reads through ESP-IDF FatFS on the SD_MMC mount). Not yet verified on hardware.
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