Fix 3.5C backlight to GPIO27 and ship GT911 capacitive touch.

Align cyd_35r with CYD guide (BL=27, INT as input after reset); export flashable firmware/cyd_35r.

Co-authored-by: Cursor <cursoragent@cursor.com>

include/pins.h

@@ -8,19 +8,27 @@
 #define SCREEN_HEIGHT 480
 #define UI_HOR_RES    480
 #define UI_VER_RES    320
+/* 3.5C capacitive GT911 (ESP32-3248S035C). GPIO33 is I2C SDA, not TOUCH_CS.
+ * BL=27; INT=21 (not shared with BL). Button stays GPIO22. */
+#define CYD_GT911_SDA  33
+#define CYD_GT911_SCL  32
+#define CYD_GT911_INT  21
+#define CYD_GT911_RST  25
+#define CYD_TFT_CS     15
 #else
 #define TFT_BL_PIN 21
 #define SCREEN_WIDTH  240
 #define SCREEN_HEIGHT 320
 #define UI_HOR_RES    320
 #define UI_VER_RES    240
-#endif
-
+/* 2.8" CYD: dedicated SoftSPI touch bus. BL=21; button GPIO22. */
 #define CYD_TOUCH_IRQ  36
 #define CYD_TOUCH_MOSI 32
 #define CYD_TOUCH_MISO 39
 #define CYD_TOUCH_CLK  25
 #define CYD_TOUCH_CS   33
+#define CYD_TFT_CS     15
+#endif
 
 /* Map 320x240 design coordinates onto the active UI resolution (identity on 2.8"). */
 #define UX(x) ((int)(((long)(x) * (UI_HOR_RES)) / 320))
@@ -28,5 +36,12 @@
 #define UW(w) UX(w)
 #define UH(h) UY(h)
 
+/* Partial frame buffer: 3.5 needs smaller ratio to fit DRAM. */
+#if defined(CYD_BOARD_3248S035)
+#define DRAW_BUF_DIV 20
+#else
+#define DRAW_BUF_DIV 10
+#endif
+
 
 #define BTN_PIN 22

include/touch.h

@@ -6,7 +6,7 @@
 void touch_init();
 void touch_read_cb(lv_indev_t *indev, lv_indev_data_t *data);
 
-// 调试：最近一次触点（物理 / LVGL 旋转后逻辑）
+// 调试：最近一次触点
 extern int16_t g_dbg_phys_x, g_dbg_phys_y;
 extern int16_t g_dbg_logic_x, g_dbg_logic_y;
 extern bool g_dbg_touch_down;