fix 3.5 backlight and GT911 for cyd_35r.

TFT_BL was wrongly GPIO21 (GT911 INT); use GPIO27, DRAW_BUF_DIV=20, and export firmware/cyd_35r.

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

include/pins.h

@@ -0,0 +1,42 @@
+#pragma once
+
+// Board pins — 2.8" default; 3.5" when CYD_BOARD_3248S035 is set (env:cyd_35r)
+
+#if defined(CYD_BOARD_3248S035)
+#define TFT_BL_PIN 27
+#define SCREEN_WIDTH  320
+#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.
+ * Backlight is GPIO27; INT is GPIO21 — they are NOT the same pin. */
+#define CYD_GT911_SDA  33
+#define CYD_GT911_SCL  32
+#define CYD_GT911_INT  21
+#define CYD_GT911_RST  25
+#else
+#define TFT_BL_PIN 21
+#define SCREEN_WIDTH  240
+#define SCREEN_HEIGHT 320
+#define UI_HOR_RES    320
+#define UI_VER_RES    240
+/* 2.8" CYD: dedicated SoftSPI touch bus. */
+#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
+#endif
+
+/* Map 320x240 design coordinates onto the active UI resolution (identity on 2.8"). */
+#define UX(x) ((int)(((long)(x) * (UI_HOR_RES)) / 320))
+#define UY(y) ((int)(((long)(y) * (UI_VER_RES)) / 240))
+#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

include/touch.h

@@ -0,0 +1,7 @@
+#pragma once
+
+#include <lvgl.h>
+#include <stdint.h>
+
+void touch_init();
+void touch_read_cb(lv_indev_t *indev, lv_indev_data_t *data);

include/wifi_prov.h

@@ -0,0 +1,82 @@
+#pragma once
+
+/**
+ * 通用 WiFi 配网核心（无 LVGL 依赖）
+ *
+ * 流程：
+ * 1. wifi_prov_begin() 读 NVS，有凭证则尝试 STA 连接
+ * 2. 失败 / 无凭证 → 业务层开屏上 UI 或 SoftAP 门户
+ * 3. wifi_prov_save() + wifi_prov_connect_to() 完成配网
+ * 4. loop 里调用 wifi_prov_loop() 做断线重连与门户处理
+ */
+
+#include <Arduino.h>
+#include <WiFi.h>
+
+#ifndef WIFI_PROV_AP_SSID
+#define WIFI_PROV_AP_SSID "CYD-Setup"
+#endif
+
+#ifndef WIFI_PROV_CONNECT_TIMEOUT_MS
+#define WIFI_PROV_CONNECT_TIMEOUT_MS 20000u
+#endif
+
+#ifndef WIFI_PROV_RECONNECT_MS
+#define WIFI_PROV_RECONNECT_MS 8000u
+#endif
+
+static constexpr int WIFI_PROV_MAX_SCAN = 16;
+static constexpr size_t WIFI_PROV_SSID_MAX = 32;
+static constexpr size_t WIFI_PROV_PASS_MAX = 64;
+
+struct WifiScanItem {
+  char ssid[WIFI_PROV_SSID_MAX + 1];
+  int32_t rssi;
+  wifi_auth_mode_t auth;
+};
+
+enum WifiProvState : uint8_t {
+  WIFI_PROV_IDLE = 0,
+  WIFI_PROV_CONNECTING,
+  WIFI_PROV_CONNECTED,
+  WIFI_PROV_FAILED,
+  WIFI_PROV_PORTAL,
+};
+
+using WifiProvStateCb = void (*)(WifiProvState state, void *user);
+
+void wifi_prov_set_state_cb(WifiProvStateCb cb, void *user = nullptr);
+
+/** 初始化 Preferences + WiFi STA；有凭证则异步开始连接。返回是否已有凭证。 */
+bool wifi_prov_begin();
+
+bool wifi_prov_has_credentials();
+bool wifi_prov_is_connected();
+WifiProvState wifi_prov_state();
+
+String wifi_prov_ssid();
+String wifi_prov_ip();
+int8_t wifi_prov_rssi();
+
+void wifi_prov_save(const char *ssid, const char *password);
+void wifi_prov_clear();
+
+/** 用已存凭证连接（异步，结果看 wifi_prov_loop / state） */
+void wifi_prov_connect_saved();
+
+/** 连接指定网络并在成功后写入 NVS */
+void wifi_prov_connect_to(const char *ssid, const char *password);
+
+/** 同步扫描，结果写入 out[]，返回条数（≤ WIFI_PROV_MAX_SCAN） */
+int wifi_prov_scan(WifiScanItem *out, int max_items);
+
+/**
+ * SoftAP + 简易 Captive Portal（手机连 CYD-Setup → http://192.168.4.1）
+ * 与屏上配网可并行；配网成功后会自动 stop。
+ */
+void wifi_prov_portal_start(const char *ap_ssid = WIFI_PROV_AP_SSID);
+void wifi_prov_portal_stop();
+bool wifi_prov_portal_active();
+
+/** 每 loop 调用：重连、门户 HTTP、状态回调 */
+void wifi_prov_loop();

include/wifi_ui.h

@@ -0,0 +1,17 @@
+#pragma once
+
+/**
+ * LVGL 屏上配网 UI（依赖 wifi_prov）
+ * 复用：拷贝 wifi_ui.* + 在业务里 wifi_ui_create() / wifi_ui_tick()
+ */
+
+void wifi_ui_create();
+void wifi_ui_tick();
+
+/** 强制进入配网页（改密 / 首次） */
+void wifi_ui_show_setup();
+
+/** 显示已连接状态页 */
+void wifi_ui_show_status();
+
+bool wifi_ui_is_setup();