[chinderdelis]

Proposed Changes

Fix and complete the existing Freenove FNK0104AB board support. All changes were validated on hardware (ESP32-S3 N16R8, 2.8" ILI9341 + FT6336G, ES8311 + FM8002E, SDMMC, WS2812).

• Freenove-FNK0104AB.ini: RGB LED is on GPIO42 (GPIO40 is SD CMD); battery divider is on GPIO9 (not 8); enable 4-bit SDMMC.
• interface.cpp: add D1/D2/D3 SD pins; mark the touch/codec I2C bus as sys_i2c so bus_HAL does not Wire.end() it and the wedged-bus recovery works; call setSysI2CBus() before touch init; attach the backlight PWM once in _pre_storage_gpio(); actually extinguish the backlight and send DISPOFF in powerOff().
• sd_functions.cpp: make 4-bit SDMMC opt-in per board via SD_MMC_4BIT (1-bit remains the default for every other board).
• touch.cpp: do not call touch.reset() for FT6X36 on every read (it toggles the hardware RST pin, making drags slow and occasionally wedging the controller).
• settings.cpp: clamp brightness to >=1 (a saved 0 leaves the screen dark with no visible UI to raise it) and disable the body touch zone while the brightness menu is open.
• .github/workflows/PR_check.yml: build the board in PR CI.

Verification

Tested on the device:

• boot, display, touch, SD card (4-bit), battery ADC (GPIO9), RGB LED (GPIO42)
• audio out (ES8311 + FM8002E), microphone
• WiFi AP + WebUI + File Manager
• BLE iBeacon advertising
• deep sleep / poweroff with BOOT wake
• Brightness menu and config saving (together with the separate config-dump fix)

Builds: Freenove FNK0104AB, plus ES3C28P as a regression check for the shared sd_functions.cpp / touch.cpp / settings.cpp changes.

Testing

Hardware tested on Freenove FNK0104AB; compile-tested on ES3C28P.

Linked Issues

N/A

User-Facing Change

Freenove FNK0104AB: fix RGB LED, battery ADC, 4-bit SD card, touch and backlight/poweroff.

Further Comments

HID/BadUSB and BLE keyboard were not tested (they require USB re-enumeration/pairing and can drop the serial console). External CC1101/NRF24 modules conflict with the broken-out pins (CC1101 io0=2 = MISO, NRF24 io0=3 = MOSI); documented in connections.md.