Fix 3.5C backlight (GPIO27) and GT911 INT handling per CYD guide.

Wrong BL=21 caused black screen; INT is separate from backlight and stays INPUT after reset.

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

firmware/README.md

@@ -1,18 +1,21 @@
 # 预编译固件（可随时刷写）
 
-当前归档目录：[`cyd/`](cyd/)
+| 目录 | 板型 | 触控 |
+|------|------|------|
+| [`cyd/`](cyd/) | **ESP32-2432S028R** 2.8"（ILI9341） | SoftSPI XPT2046 |
+| [`cyd_35r/`](cyd_35r/) | **ESP32-3248S035C** 3.5"（ST7796） | GT911 电容 |
 
-对应板子：**CYD ESP32-2432S028R**（ILI9341）  
-功能：电子相册（JPG / PNG / GIF）+ SoftSPI 触控 + TF 卡  
-版本信息见 [`cyd/VERSION.txt`](cyd/VERSION.txt)。
+功能：电子相册（JPG / PNG / GIF）+ TF 卡。版本见各目录 `VERSION.txt`。
 
 ## 直接刷写（无需重新编译）
 
 1. USB 连接板子  
-2. 执行：
+2. 按板型进入对应目录：
 
 ```powershell
-cd firmware\cyd
+cd firmware\cyd        # 2.8"
+# 或
+cd firmware\cyd_35r    # 3.5C
 .\flash.ps1
 # 或指定端口
 .\flash.ps1 -Port COM3
@@ -41,7 +44,9 @@ esptool.py --chip esp32 --port COM3 --baud 921600 write_flash -z ^
 在仓库根目录：
 
 ```powershell
-.\firmware\export_from_build.ps1
+.\firmware\export_from_build.ps1              # 2.8 → firmware\cyd
+.\firmware\export_from_build.ps1 -Env cyd_35r # 3.5 → firmware\cyd_35r
 # 仅复制、不编译：
 .\firmware\export_from_build.ps1 -SkipBuild
+.\firmware\export_from_build.ps1 -Env cyd_35r -SkipBuild
 ```

firmware/cyd_35r/VERSION.txt

@@ -0,0 +1,15 @@
+name: CYD phtotest (cyd_35r)
+git: f870f5c
+date: 2026-10-25
+board: ESP32-3248S035 (ST7796)
+flash_size: 4MB
+offsets:
+  0x1000  bootloader.bin
+  0x8000  partitions.bin
+  0xe000  boot_app0.bin
+  0x10000 firmware.bin
+sha256:
+  bootloader.bin  3D234A7471F67B013686DABD4DEE7C1FA915C9928463616A94BC9297ACF1ABF8
+  boot_app0.bin   F94C5D786A7A8FAB06AC5D10E33BF37711A6697636DC037559EA19CC410A17F0
+  firmware.bin    D10883DC87626DD5544015D63FF7BA788DB38A909DC32227AA1C57FBB55C7B50
+  partitions.bin  148B959CBFF1C38AA8E1D5C0BA9D612C54997B945E56A63F41223EEF650653A1

firmware/cyd_35r/flash.bat

@@ -0,0 +1,5 @@
+@echo off
+setlocal
+cd /d "%~dp0"
+powershell -NoProfile -ExecutionPolicy Bypass -File "%~dp0flash.ps1" %*
+exit /b %ERRORLEVEL%

firmware/cyd_35r/flash.ps1

@@ -0,0 +1,98 @@
+# Flash archived CYD TF+Speaker firmware (no rebuild needed)
+# Usage:
+#   .\flash.ps1
+#   .\flash.ps1 -Port COM5
+#   .\flash.ps1 -Port COM5 -Baud 460800
+
+param(
+  [string]$Port = "",
+  [int]$Baud = 921600
+)
+
+$ErrorActionPreference = "Stop"
+$here = Split-Path -Parent $MyInvocation.MyCommand.Path
+Set-Location $here
+
+function Find-Esptool {
+  $pio = Get-Command pio -ErrorAction SilentlyContinue
+  if (-not $pio) {
+    $pioPath = Join-Path $env:USERPROFILE "AppData\Local\Programs\Python\Python312\Scripts\pio.exe"
+    if (Test-Path $pioPath) {
+      $env:Path = "$(Split-Path $pioPath);$env:Path"
+      $pio = Get-Command pio -ErrorAction SilentlyContinue
+    }
+  }
+  if ($pio) {
+    $pkg = Join-Path $env:USERPROFILE ".platformio\packages\tool-esptoolpy\esptool.py"
+    if (Test-Path $pkg) { return @{ Kind = "py"; Path = $pkg } }
+  }
+  $py = Get-Command python -ErrorAction SilentlyContinue
+  if ($py) {
+    try {
+      & python -c "import esptool" 2>$null
+      if ($LASTEXITCODE -eq 0) { return @{ Kind = "mod"; Path = "esptool" } }
+    } catch {}
+  }
+  $esp = Get-Command esptool.py -ErrorAction SilentlyContinue
+  if ($esp) { return @{ Kind = "py"; Path = $esp.Source } }
+  return $null
+}
+
+if (-not $Port) {
+  $ports = @()
+  try {
+    Add-Type -AssemblyName System.IO.Ports -ErrorAction SilentlyContinue | Out-Null
+    $ports = [System.IO.Ports.SerialPort]::GetPortNames() | Sort-Object
+  } catch {}
+  if (-not $ports -or $ports.Count -eq 0) {
+    $ports = Get-CimInstance Win32_SerialPort -ErrorAction SilentlyContinue |
+      Select-Object -ExpandProperty DeviceID | Sort-Object
+  }
+  if (-not $ports -or $ports.Count -eq 0) {
+    Write-Error "No serial ports found. Plug in the CYD USB cable, then retry with -Port COMx"
+  }
+  if ($ports.Count -eq 1) {
+    $Port = $ports[0]
+  } else {
+    Write-Host "Available ports: $($ports -join ', ')"
+    $Port = $ports[-1]
+    Write-Host "Using last port: $Port (override with -Port)"
+  }
+}
+
+$tool = Find-Esptool
+if (-not $tool) {
+  Write-Error "esptool not found. Install PlatformIO (`pio`) or: pip install esptool"
+}
+
+$needed = @("bootloader.bin", "partitions.bin", "boot_app0.bin", "firmware.bin")
+foreach ($f in $needed) {
+  if (-not (Test-Path (Join-Path $here $f))) {
+    Write-Error "Missing $f — run ..\export_from_build.ps1 from repo root first"
+  }
+}
+
+$argsCommon = @(
+  "--chip", "esp32",
+  "--port", $Port,
+  "--baud", "$Baud",
+  "--before", "default_reset",
+  "--after", "hard_reset",
+  "write_flash", "-z",
+  "--flash_mode", "dio",
+  "--flash_freq", "40m",
+  "--flash_size", "4MB",
+  "0x1000", "bootloader.bin",
+  "0x8000", "partitions.bin",
+  "0xe000", "boot_app0.bin",
+  "0x10000", "firmware.bin"
+)
+
+Write-Host "Flashing $here -> $Port @ $Baud"
+if ($tool.Kind -eq "mod") {
+  & python -m esptool @argsCommon
+} else {
+  & python $tool.Path @argsCommon
+}
+if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
+Write-Host "Done. Open serial monitor at 115200 if needed."

firmware/cyd_35r/media/preview.html

@@ -0,0 +1,51 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+<meta charset="utf-8" />
+<title>PHOTOS</title>
+<style>
+  *{box-sizing:border-box;margin:0;padding:0}
+  html,body{width:320px;height:240px;overflow:hidden;background:#000;margin:0}
+  .bezel{width:320px;height:240px;background:#1a1408}
+  .screen{width:320px;height:240px;background:#0A1016;color:#EAF0F6;font:12px/1.2 system-ui,sans-serif;
+    display:flex;flex-direction:column;overflow:hidden;}
+  .top{height:28px;display:flex;align-items:center;padding:0 10px;gap:10px}
+  .top .t{color:#4FC3F7;font-weight:700;font-size:14px}
+  .top .i{margin-left:auto;color:#EAF0F6}
+  .top .c{color:#3DDC97}
+  .stage{flex:1;margin:0 10px;border-radius:6px;background:
+    linear-gradient(145deg,#1a2836,#0d141c 55%,#152030);
+    border:1px solid #1C2A38;position:relative;overflow:hidden}
+  .stage::before{
+    content:"";position:absolute;inset:16px 28px;border-radius:4px;
+    background:
+      linear-gradient(120deg,rgba(79,195,247,.25),transparent 40%),
+      linear-gradient(200deg,#2a3d52,#15202c);
+    box-shadow:inset 0 0 0 1px rgba(234,240,246,.08);
+  }
+  .stage .name{position:absolute;left:12px;right:12px;bottom:10px;text-align:center;
+    color:#EAF0F6;font-size:12px;z-index:1}
+  .bot{height:44px;display:flex;align-items:center;justify-content:center;gap:10px;padding:0 10px}
+  .btn{min-width:72px;height:28px;border:0;border-radius:6px;background:#243140;color:#EAF0F6;font-weight:600}
+  .btn.next{background:#1A4A6E}
+  .hint{position:absolute;bottom:52px;left:0;right:0;text-align:center;color:#7A8B9C;font-size:11px}
+
+/* CYD 3.5" full-bleed: non-uniform scale matches firmware UX()/UY(). */
+html,body{width:480px!important;height:320px!important;overflow:hidden!important;background:#000!important;margin:0!important;padding:0!important}
+.cyd35-scale{width:320px;height:240px;transform:scale(1.5,1.3333333333);transform-origin:0 0;overflow:hidden}
+</style>
+</head>
+<body>
+<div class="cyd35-scale">
+
+<div class="bezel"><div class="screen" id="s">
+  <div class="top"><span class="t">PHOTOS</span><span class="i">3 / 12</span><span class="c">TF OK</span></div>
+  <div class="stage"><div class="name">sunset.jpg</div></div>
+  <div class="hint">tap · SoftSPI touch</div>
+  <div class="bot"><button class="btn" type="button">PREV</button><button class="btn next" type="button">NEXT</button></div>
+</div></div>
+
+
+</div>
+</body>
+</html>

firmware/cyd_35r/meta.json

@@ -0,0 +1,17 @@
+{
+  "boardId": "esp32-3248s035",
+  "name": "CYD Photo album (3.5\")",
+  "summary": "TF card photo album with GT911 capacitive touch",
+  "description": "JPG/PNG/GIF album from TF card on ESP32-3248S035C (ST7796 + GT911). Prev/Next tap or buttons. Backlight GPIO27.",
+  "tags": [
+    "photo",
+    "album",
+    "tf",
+    "touch",
+    "gt911",
+    "3.5"
+  ],
+  "media": {
+    "preview": "media/preview.html"
+  }
+}