Fix 3.5" black screen: drive backlight on GPIO27, not GPIO21.

GPIO21 is GT911 INT on 3248S035C; PWM on the wrong pin left the panel dark. Co-authored-by: Cursor <cursoragent@cursor.com>
2026-10-25 10:34:00 +08:00
parent 0a1b612cc9
commit 83b1bdc5f7
7 changed files with 13 additions and 15 deletions
--- a/platformio.ini
+++ b/platformio.ini
@@ -69,6 +69,7 @@ build_flags =
 ; Optional 3.5" CYD ESP32-3248S035C (ST7796 + GT911 capacitive). Default remains cyd_28r.
 ; Build: pio run -e cyd_35r
 ; Keep TOUCH_CS=-1 — GPIO33 is GT911 SDA, not resistive touch CS.
+; TFT_BL=GPIO27 (not 21 — 21 is GT911 INT on C boards).
 [env:cyd_35r]
 lib_deps =
  lvgl/lvgl@9.2.2
@@ -83,7 +84,7 @@ build_flags =
  -DTFT_WIDTH=320
  -DTFT_HEIGHT=480
  -UTFT_BL
-  -DTFT_BL=21
+  -DTFT_BL=27
  -DCYD_BOARD_3248S035=1
  -DSUPPORT_TRANSACTIONS
  -DTFT_RGB_ORDER=TFT_BGR