feature/jc3248w535: Add Guition JC3248W535

[cosmicpsyop]

Guition JC3248W535

Video Demo>>

Adds a complete display driver for the Guition JC3248W535 (AXS15231B, QSPI, 480×320 landscape) panel as used in some NerdMiner v2 devices. Biggest issue is a display flicker due to a complete frame buffer flush each tick, Mitigation gates backlight during flushes to eliminate visible redraw flicker.

Current flush / flicker strategy

Original problem: every gfx->flush() pushes the entire 480×320 framebuffer:
480 × 320 × 2 = 307,200 bytes

That visibly flashed the screen when it occurred every tick.

Included:

Rendering engine - PSRAM framebuffer (Arduino_Canvas) + separate bg_cache for artifact-free text erase — no more black boxes or ghosted digits when values change width. OpenFontRender TTF rasterizer for DigitalNumbers and NotoBold fonts. Hysteresis quantizers on hashrate and temperature to suppress per-tick snapshot oscillation

Backlight gating - jc_flushGated() turns the backlight off during the ~35ms panel write, back on after — dark period is below human perception. jc_backlight_enabled bool tracks intended state (v0.9.18: replaces fragile digitalRead on an output pin)

Smart flushing - Snapshot-based dirty detection — only pushes the 307KB framebuffer when displayed content actually changes (or every 60s safety net). jc_flushOrPushRect() is a no-op under partial-flush; end-of-frame handles the single flush (prevents flush storms)

Touch - AXS-touch I2C @ 0x3B, polled at NerdMiner's 10Hz cadence with 200ms debounce. Top-half tap → next screen; bottom-half tap → toggle Pool/Fees panel

Arduino_GFX_Library 1.6.0 (pinned — 1.6.1+ breaks AXS15231B QSPI init)
moononournation/Arduino_GFX#803

Fix - Replace board-specific fee guards with SCREEN_FEES_ENABLE

Features and diagnostics:

;-D DEBUG_MINING=1
;    General mining debug logging.

;-D JC_TOUCH_DEBUG=1
;    On-screen touch poll/hit counters and raw/tap coordinate readout.

;-D JC_NO_TOUCH_POLL=1
;    A/B isolation: disable AXS I2C touch polling.
;    v0.9.2 ruled out touch polling as SD drop cause.

;-D JC_NO_SD_PIXEL=1
;    A/B isolation: disable SD status pixel and SD status queries.

;-D JC_LOG_SNAPSHOTS=1
;    Diagnostic: log snapshot strings once/sec/screen to identify which field changes.

-D JC_NO_SLIDESHOW=1
    Compile out JPEG slideshow / TJpg_Decoder path.

;-D JC_NO_SNAPSHOT=1
;    A/B test: bypass snapshot/quantization and force gated full flush every tick.

JPEG Slideshow with NerdMiner Stats (Experimental)

Slideshow screen — reads /pic/*.jpg (configurable), decodes via TJpgDec directly into the framebuffer MCU-by-MCU (no extra buffer needed), and renders a bottom stats overlay showing current time, BTC price, and block height. Images larger than the panel are auto-scaled to fit. Auto-advances on a configurable timer; bottom-half tap advances immediately, top-half tap returns to the next cyclic screen. Gracefully handles missing SD card or empty directory. JPEG decode failures display a human-readable error reason on screen instead of a raw code.

Recommended ImageMagick command format image compatible with library:

magick image.jpg \
  -resize 480x320! \
  -colorspace sRGB \
  -interlace none \
  -sampling-factor 4:2:0 \
  -quality 85 \
  converted-image.jpg

Subsystem overview

Subsystem	Status
Display (AXS15231B QSPI, 480×320 landscape)	✅ working
Touch (AXS @ I²C 0x3B, polled @ 10 Hz, debounced)	✅ working
5 cyclic screens (Miner / Clock / GlobalHash / Price / Slideshow)	✅ working
Two-zone touch (top = next screen, bottom = pool ⇄ fees or slideshow image advance)	✅ working
Backgrounds (canonical art, scaled to 480×320 layout, pre-rendered slabs in PSRAM)	✅ working
OpenFontRender (DigitalNumbers + NotoSans Bold)	✅ working
Pool stats / BTC price / fees / block height	✅ working
WiFi via captive portal	✅ working
Serial via USB-CDC (HWCDC)	🟡 works, with known quirk
SD card (SDMMC 1-bit, 20 MHz, internal pull-ups, stays mounted)	✅ working
SD status pixel (4×4 px at bottom-left)	✅ working
Per-second screen flash on data update	🟢 mitigated by snapshot hysteresis + backlight-gated full flush
Partial sub-rect flush	🔴 not production-ready; historical path must remain disabled until corrected jc_pushRect() is validated

Credit

• F1ATB / AudunKodehode for working JC3248W535EN AXS15231B reference sample.
• moononournation for Arduino_GFX_Library and the AXS15231B panel class.
• BitMaker-hub NerdMiner_v2 community for the driver framework.