Add LCD1602A I2C test with SoftSPI touch and LVGL.

PCF8574 backpack on SDA=GPIO22/SCL=GPIO27, demo/hello/clear/backlight UI, and flashable firmware/cyd package.

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

.gitignore

@@ -0,0 +1,13 @@
+.pio/
+.vscode/.browse.c_cpp.db*
+.vscode/c_cpp_properties.json
+.vscode/launch.json
+.vscode/ipch
+*.pyc
+__pycache__/
+.DS_Store
+Thumbs.db
+assets/
+*.elf
+# 构建目录里的 bin 不入库；firmware/ 预编译包要入库
+!firmware/**/*.bin

README.md

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+# LCD1602A 液晶（CYD）
+
+触控 + LVGL 参考 `tftest` / `hw269test` / `hw069digitdisplaytest`。  
+LCD1602A（HD44780）经 **PCF8574 I2C 转接板** 驱动：改两行文字、清屏、背光。
+
+## 硬件
+
+| 项目 | 说明 |
+|------|------|
+| 板子 | CYD ESP32-2432S028R |
+| 模块 | LCD1602A + I2C 背包（PCF8574，常见地址 **0x27 / 0x3F**） |
+| SDA | **GPIO22** |
+| SCL | **GPIO27** |
+
+接线：
+
+| LCD1602A(I2C) | CYD |
+|---------------|-----|
+| VCC | **5V**（屏对比度更稳；多数模块也可试 3.3V） |
+| GND | GND |
+| SDA | GPIO22 |
+| SCL | GPIO27 |
+
+上电会扫描 `0x27 / 0x3F / 0x26 / 0x3E`。串口与 TFT 状态栏会显示是否找到地址。
+
+## 操作
+
+- 中间两行：当前 LCD 内容预览（16 字符/行）
+- **Demo**：循环示例文案
+- **Hello**：`Hello World!` / `LCD1602A`
+- **Clear**：清屏
+- **BL ON/OFF**：背光开关
+
+## 构建 / 烧录
+
+```powershell
+pio run -e cyd -t upload
+```
+
+## 预编译固件
+
+```powershell
+cd firmware\cyd
+.\flash.ps1
+# 或 .\flash.ps1 -Port COMx
+```
+
+重新导出：
+
+```powershell
+.\firmware\export_from_build.ps1
+```

copy_lv_conf.py

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+Import("env")  # noqa: F821
+from pathlib import Path
+
+src = Path(env["PROJECT_DIR"]) / "include" / "lv_conf.h"  # noqa: F821
+dst_dir = Path(env["PROJECT_LIBDEPS_DIR"]) / env["PIOENV"]  # noqa: F821
+dst_dir.mkdir(parents=True, exist_ok=True)
+dst = dst_dir / "lv_conf.h"
+if src.exists():
+    dst.write_text(src.read_text(encoding="utf-8"), encoding="utf-8")
+    lvgl = dst_dir / "lvgl" / "lv_conf.h"
+    if (dst_dir / "lvgl").exists():
+        lvgl.write_text(src.read_text(encoding="utf-8"), encoding="utf-8")
+    print(f"copy_lv_conf: synced -> {dst}")

firmware/README.md

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+# 预编译固件
+
+目录：[`cyd/`](cyd/)
+
+板子：**CYD ESP32-2432S028R**（ILI9341）  
+功能：LCD1602A I2C（SDA=GPIO22，SCL=GPIO27，PCF8574）+ SoftSPI 触控 + LVGL
+
+## 刷写
+
+```powershell
+cd firmware\cyd
+.\flash.ps1
+# 或 .\flash.ps1 -Port COM3
+```
+
+## 重新打包
+
+```powershell
+.\firmware\export_from_build.ps1
+.\firmware\export_from_build.ps1 -SkipBuild
+```

firmware/cyd/VERSION.txt

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+name: CYD LCD1602A (cyd)
+git: unknown
+date: 2026-10-23
+board: ESP32-2432S028R (ILI9341)
+features: SoftSPI touch, LVGL, LCD1602A I2C SDA=GPIO22 SCL=GPIO27 PCF8574
+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    6A01742209690884333761FB7C4437965DF816F51771E93539A39CE32FD0E8C4
+  partitions.bin  148B959CBFF1C38AA8E1D5C0BA9D612C54997B945E56A63F41223EEF650653A1

firmware/cyd/flash.bat

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

firmware/cyd/flash.ps1

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+# Flash archived CYD LCD1602A 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/meta.json

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+{
+  "boardId": "esp32-2432s028",
+  "name": "CYD LCD1602A",
+  "summary": "LCD1602A HD44780 via PCF8574 I2C: SDA GPIO22, SCL GPIO27 — demo / hello / clear / backlight",
+  "description": "SoftSPI touch + LVGL. LCD1602A character LCD on I2C backpack (scan 0x27/0x3F).",
+  "tags": ["lcd1602a", "hd44780", "pcf8574", "i2c", "display", "touch", "lvgl"]
+}

firmware/export_from_build.ps1

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+# Rebuild (optional) and refresh firmware/cyd from PlatformIO build output.
+# Usage:
+#   .\firmware\export_from_build.ps1
+#   .\firmware\export_from_build.ps1 -SkipBuild
+
+param([switch]$SkipBuild)
+
+$ErrorActionPreference = "Stop"
+$root = Split-Path -Parent (Split-Path -Parent $MyInvocation.MyCommand.Path)
+Set-Location $root
+
+$env:Path = "C:\Users\dsx2016\AppData\Local\Programs\Python\Python312\Scripts;" + $env:Path
+
+if (-not $SkipBuild) {
+  pio run -e cyd
+  if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
+}
+
+$src = Join-Path $root ".pio\build\cyd"
+$dst = Join-Path $root "firmware\cyd"
+New-Item -ItemType Directory -Force -Path $dst | Out-Null
+
+foreach ($f in @("bootloader.bin", "partitions.bin", "firmware.bin")) {
+  $p = Join-Path $src $f
+  if (-not (Test-Path $p)) { Write-Error "Missing build artifact: $p" }
+  Copy-Item $p $dst -Force
+}
+
+$bootApp = Join-Path $env:USERPROFILE ".platformio\packages\framework-arduinoespressif32\tools\partitions\boot_app0.bin"
+if (-not (Test-Path $bootApp)) {
+  Write-Error "boot_app0.bin not found under PlatformIO packages"
+}
+Copy-Item $bootApp (Join-Path $dst "boot_app0.bin") -Force
+
+$git = ""
+try { $git = (git -C $root rev-parse --short HEAD).Trim() } catch { $git = "unknown" }
+$date = Get-Date -Format "yyyy-MM-dd"
+$hashes = Get-ChildItem (Join-Path $dst "*.bin") | Get-FileHash -Algorithm SHA256
+$lines = @(
+  "name: CYD LCD1602A (cyd)",
+  "git: $git",
+  "date: $date",
+  "board: ESP32-2432S028R (ILI9341)",
+  "features: SoftSPI touch, LVGL, LCD1602A I2C SDA=GPIO22 SCL=GPIO27 PCF8574",
+  "flash_size: 4MB",
+  "offsets:",
+  "  0x1000  bootloader.bin",
+  "  0x8000  partitions.bin",
+  "  0xe000  boot_app0.bin",
+  "  0x10000 firmware.bin",
+  "sha256:"
+)
+foreach ($h in $hashes) {
+  $lines += ("  {0,-15} {1}" -f (Split-Path $h.Path -Leaf), $h.Hash)
+}
+$lines | Set-Content -Encoding utf8 (Join-Path $dst "VERSION.txt")
+Write-Host "Exported -> $dst (git $git)"

include/lcd.h

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+#pragma once
+
+#include <stddef.h>
+#include <stdint.h>
+
+void lcd_init();
+
+bool lcd_ok();
+uint8_t lcd_addr();
+
+void lcd_set_backlight(bool on);
+bool lcd_backlight();
+
+void lcd_clear();
+void lcd_set_line(uint8_t row, const char *text);
+void lcd_get_line(uint8_t row, char *out, size_t out_len);
+
+/** 写入两行示例文案并点亮背光 */
+void lcd_demo(uint8_t index);
+uint8_t lcd_demo_count();

include/pins.h

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+#pragma once
+
+// CYD ESP32-2432S028R — 触控/屏脚与 tftest 一致
+// LCD1602A + I2C 转接板（PCF8574）：SDA=GPIO22，SCL=GPIO27
+// 常见地址 0x27 / 0x3F（上电扫描）
+
+#define TFT_BL_PIN 21
+
+#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 LCD_I2C_SDA_PIN 22
+#define LCD_I2C_SCL_PIN 27
+#define LCD_I2C_FREQ_HZ 100000
+#define LCD_COLS 16
+#define LCD_ROWS 2
+
+#define SCREEN_WIDTH  240
+#define SCREEN_HEIGHT 320
+#define UI_HOR_RES    320
+#define UI_VER_RES    240

include/touch.h

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+#pragma once
+
+#include <lvgl.h>
+#include <stdint.h>
+
+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）
+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;

include/ui.h

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+#pragma once
+
+void ui_create();
+void ui_refresh_lcd();

platformio.ini

@@ -0,0 +1,56 @@
+; CYD ESP32-2432S028 — LCD1602A I2C(SDA22/SCL27) + SoftSPI 触控 + LVGL
+; 触控/屏配置参考 tftest / hw269test / hw069digitdisplaytest
+[env:cyd]
+platform = espressif32
+board = esp32dev
+framework = arduino
+monitor_speed = 460800
+upload_speed = 460800
+board_build.partitions = default.csv
+
+lib_deps =
+  bodmer/TFT_eSPI@^2.5.43
+  lvgl/lvgl@9.2.2
+
+build_flags =
+  -DCORE_DEBUG_LEVEL=0
+  -DUSER_SETUP_LOADED=1
+  -DILI9341_2_DRIVER=1
+  -DTFT_WIDTH=240
+  -DTFT_HEIGHT=320
+  -DTFT_MISO=12
+  -DTFT_MOSI=13
+  -DTFT_SCLK=14
+  -DTFT_CS=15
+  -DTFT_DC=2
+  -DTFT_RST=-1
+  -DTFT_BL=21
+  -DTFT_BACKLIGHT_ON=HIGH
+  -DTOUCH_CS=-1
+  -DLOAD_GLCD=1
+  -DLOAD_FONT2=1
+  -DLOAD_FONT4=1
+  -DLOAD_FONT6=1
+  -DLOAD_FONT7=1
+  -DLOAD_FONT8=1
+  -DLOAD_GFXFF=1
+  -DSMOOTH_FONT=1
+  -DSPI_FREQUENCY=40000000
+  -DSPI_READ_FREQUENCY=20000000
+  -DLV_CONF_SKIP
+  -DLV_COLOR_DEPTH=16
+  -DLV_MEM_SIZE=49152
+  -DLV_FONT_MONTSERRAT_14=1
+  -DLV_FONT_MONTSERRAT_16=1
+  -DLV_FONT_MONTSERRAT_18=1
+  -DLV_FONT_MONTSERRAT_20=1
+  -DLV_FONT_MONTSERRAT_28=1
+  -DLV_USE_TFT_ESPI=1
+  -DLV_USE_FLEX=1
+  -DLV_USE_BUTTON=1
+  -DLV_USE_LABEL=1
+  -DLV_USE_BAR=1
+  -DLV_USE_SLIDER=1
+  -I${PROJECT_DIR}/include
+
+extra_scripts = pre:copy_lv_conf.py

src/lcd.cpp

@@ -0,0 +1,221 @@
+#include "lcd.h"
+#include "pins.h"
+
+#include <Arduino.h>
+#include <Wire.h>
+#include <string.h>
+
+// PCF8574 背包常见接线：P0=RS P1=RW P2=E P3=BL P4..P7=D4..D7
+static constexpr uint8_t BIT_RS = 0x01;
+static constexpr uint8_t BIT_RW = 0x02;
+static constexpr uint8_t BIT_E = 0x04;
+static constexpr uint8_t BIT_BL = 0x08;
+
+static constexpr uint8_t CANDIDATE_ADDRS[] = {0x27, 0x3F, 0x26, 0x3E};
+
+struct DemoMsg {
+  const char *line0;
+  const char *line1;
+};
+
+static const DemoMsg DEMOS[] = {
+    {"Hello CYD!", "LCD1602A I2C"},
+    {"SDA=GPIO22", "SCL=GPIO27"},
+    {"Line1 16 chars!", "Line2 ready...."},
+    {"Backlight ON", "Touch UI demo"},
+};
+
+static bool g_ok = false;
+static bool g_bl = true;
+static uint8_t g_addr = 0;
+static char g_lines[LCD_ROWS][LCD_COLS + 1];
+
+static uint8_t bl_mask() { return g_bl ? BIT_BL : 0; }
+
+static bool i2c_write(uint8_t data) {
+  Wire.beginTransmission(g_addr);
+  Wire.write(data);
+  return Wire.endTransmission() == 0;
+}
+
+static void pulse_enable(uint8_t data) {
+  i2c_write((uint8_t)(data | BIT_E));
+  delayMicroseconds(1);
+  i2c_write((uint8_t)(data & (uint8_t)~BIT_E));
+  delayMicroseconds(50);
+}
+
+static void write4(uint8_t nibble, uint8_t mode) {
+  const uint8_t data = (uint8_t)((nibble & 0xF0) | mode | bl_mask());
+  i2c_write(data);
+  pulse_enable(data);
+}
+
+static void send(uint8_t value, uint8_t mode) {
+  write4((uint8_t)(value & 0xF0), mode);
+  write4((uint8_t)((value << 4) & 0xF0), mode);
+}
+
+static void cmd(uint8_t c) {
+  send(c, 0);
+  if (c <= 0x03) {
+    delay(2);
+  }
+}
+
+static void data(uint8_t d) { send(d, BIT_RS); }
+
+static void pad_copy(char *dst, const char *src) {
+  size_t i = 0;
+  if (src) {
+    for (; i < LCD_COLS && src[i]; ++i) {
+      dst[i] = src[i];
+    }
+  }
+  for (; i < LCD_COLS; ++i) {
+    dst[i] = ' ';
+  }
+  dst[LCD_COLS] = '\0';
+}
+
+static void write_row(uint8_t row) {
+  if (!g_ok || row >= LCD_ROWS) {
+    return;
+  }
+  cmd((uint8_t)(0x80 | (row == 0 ? 0x00 : 0x40)));
+  for (uint8_t i = 0; i < LCD_COLS; ++i) {
+    data((uint8_t)g_lines[row][i]);
+  }
+}
+
+static bool probe_addr(uint8_t addr) {
+  Wire.beginTransmission(addr);
+  return Wire.endTransmission() == 0;
+}
+
+static bool hd44780_init() {
+  delay(50);
+  // 强制 8-bit 再切 4-bit（手册上电时序）
+  write4(0x30, 0);
+  delay(5);
+  write4(0x30, 0);
+  delayMicroseconds(150);
+  write4(0x30, 0);
+  delayMicroseconds(150);
+  write4(0x20, 0); // 4-bit
+  delayMicroseconds(150);
+
+  cmd(0x28); // 4-bit, 2 lines, 5x8
+  cmd(0x0C); // display on, cursor off
+  cmd(0x06); // entry mode
+  cmd(0x01); // clear
+  delay(2);
+  return true;
+}
+
+void lcd_init() {
+  memset(g_lines, 0, sizeof(g_lines));
+  pad_copy(g_lines[0], "LCD1602A");
+  pad_copy(g_lines[1], "init...");
+
+  Wire.begin(LCD_I2C_SDA_PIN, LCD_I2C_SCL_PIN, (uint32_t)LCD_I2C_FREQ_HZ);
+  delay(20);
+
+  g_ok = false;
+  g_addr = 0;
+  g_bl = true;
+
+  for (uint8_t a : CANDIDATE_ADDRS) {
+    if (probe_addr(a)) {
+      g_addr = a;
+      g_ok = true;
+      Serial.printf("LCD1602A PCF8574 found @ 0x%02X\n", g_addr);
+      break;
+    }
+  }
+
+  if (!g_ok) {
+    Serial.printf("LCD1602A NOT FOUND (SDA=GPIO%d SCL=GPIO%d). Tried:",
+                  LCD_I2C_SDA_PIN, LCD_I2C_SCL_PIN);
+    for (uint8_t a : CANDIDATE_ADDRS) {
+      Serial.printf(" 0x%02X", a);
+    }
+    Serial.println();
+    pad_copy(g_lines[0], "NO I2C LCD");
+    pad_copy(g_lines[1], "check wiring");
+    return;
+  }
+
+  if (!hd44780_init()) {
+    g_ok = false;
+    Serial.println("LCD1602A HD44780 init failed");
+    return;
+  }
+
+  write_row(0);
+  write_row(1);
+  Serial.printf("LCD1602A OK SDA=GPIO%d SCL=GPIO%d addr=0x%02X\n",
+                LCD_I2C_SDA_PIN, LCD_I2C_SCL_PIN, g_addr);
+}
+
+bool lcd_ok() { return g_ok; }
+
+uint8_t lcd_addr() { return g_addr; }
+
+void lcd_set_backlight(bool on) {
+  g_bl = on;
+  if (!g_ok) {
+    return;
+  }
+  i2c_write(bl_mask());
+  Serial.printf("LCD backlight %s\n", g_bl ? "ON" : "OFF");
+}
+
+bool lcd_backlight() { return g_bl; }
+
+void lcd_clear() {
+  pad_copy(g_lines[0], "");
+  pad_copy(g_lines[1], "");
+  if (!g_ok) {
+    return;
+  }
+  cmd(0x01);
+  delay(2);
+  Serial.println("LCD clear");
+}
+
+void lcd_set_line(uint8_t row, const char *text) {
+  if (row >= LCD_ROWS) {
+    return;
+  }
+  pad_copy(g_lines[row], text);
+  write_row(row);
+  Serial.printf("LCD L%u: [%s]\n", (unsigned)row, g_lines[row]);
+}
+
+void lcd_get_line(uint8_t row, char *out, size_t out_len) {
+  if (!out || out_len == 0) {
+    return;
+  }
+  if (row >= LCD_ROWS) {
+    out[0] = '\0';
+    return;
+  }
+  strncpy(out, g_lines[row], out_len - 1);
+  out[out_len - 1] = '\0';
+}
+
+uint8_t lcd_demo_count() { return (uint8_t)(sizeof(DEMOS) / sizeof(DEMOS[0])); }
+
+void lcd_demo(uint8_t index) {
+  if (lcd_demo_count() == 0) {
+    return;
+  }
+  index = (uint8_t)(index % lcd_demo_count());
+  g_bl = true;
+  if (g_ok) {
+    i2c_write(bl_mask());
+  }
+  lcd_set_line(0, DEMOS[index].line0);
+  lcd_set_line(1, DEMOS[index].line1);
+}

src/main.cpp

@@ -0,0 +1,45 @@
+#include <Arduino.h>
+#include <lvgl.h>
+
+#include "lcd.h"
+#include "pins.h"
+#include "touch.h"
+#include "ui.h"
+
+static constexpr uint32_t DRAW_BUF_SIZE =
+    (SCREEN_WIDTH * SCREEN_HEIGHT / 10 * (LV_COLOR_DEPTH / 8));
+static uint32_t draw_buf[DRAW_BUF_SIZE / 4];
+
+void setup() {
+  Serial.begin(460800);
+  delay(200);
+  Serial.println();
+  Serial.printf("LVGL %d.%d.%d | LCD1602A I2C\n", lv_version_major(),
+                lv_version_minor(), lv_version_patch());
+  Serial.println("BOOT_OK");
+
+  pinMode(TFT_BL_PIN, OUTPUT);
+  digitalWrite(TFT_BL_PIN, HIGH);
+
+  touch_init();
+  lcd_init();
+
+  lv_init();
+
+  lv_display_t *disp =
+      lv_tft_espi_create(SCREEN_WIDTH, SCREEN_HEIGHT, draw_buf, sizeof(draw_buf));
+  lv_display_set_rotation(disp, LV_DISPLAY_ROTATION_270);
+
+  lv_indev_t *indev = lv_indev_create();
+  lv_indev_set_type(indev, LV_INDEV_TYPE_POINTER);
+  lv_indev_set_read_cb(indev, touch_read_cb);
+  lv_indev_set_display(indev, disp);
+
+  ui_create();
+}
+
+void loop() {
+  lv_timer_handler();
+  lv_tick_inc(5);
+  delay(5);
+}

src/touch.cpp

@@ -0,0 +1,125 @@
+#include "touch.h"
+#include "pins.h"
+
+#include <Arduino.h>
+
+/**
+ * SoftSPI XPT2046
+ * BL↔TR 是矩形主对角线镜像（XY 对调），不是 180°（180° 会搞成 TL↔BR）。
+ * 先按 rot2 得到旧 UI，再做对角修正，反变换喂给 LVGL 270。
+ */
+
+int16_t g_dbg_phys_x = -1;
+int16_t g_dbg_phys_y = -1;
+int16_t g_dbg_logic_x = -1;
+int16_t g_dbg_logic_y = -1;
+bool g_dbg_touch_down = false;
+
+static void soft_write(uint8_t data) {
+  for (int i = 7; i >= 0; --i) {
+    digitalWrite(CYD_TOUCH_MOSI, (data >> i) & 1);
+    digitalWrite(CYD_TOUCH_CLK, HIGH);
+    delayMicroseconds(2);
+    digitalWrite(CYD_TOUCH_CLK, LOW);
+    delayMicroseconds(2);
+  }
+}
+
+static uint16_t soft_read12() {
+  uint16_t v = 0;
+  digitalWrite(CYD_TOUCH_CLK, HIGH);
+  delayMicroseconds(2);
+  digitalWrite(CYD_TOUCH_CLK, LOW);
+  delayMicroseconds(2);
+  for (int i = 0; i < 12; ++i) {
+    digitalWrite(CYD_TOUCH_CLK, HIGH);
+    delayMicroseconds(2);
+    v = (uint16_t)((v << 1) | (digitalRead(CYD_TOUCH_MISO) ? 1u : 0u));
+    digitalWrite(CYD_TOUCH_CLK, LOW);
+    delayMicroseconds(2);
+  }
+  return v;
+}
+
+static uint16_t xpt_read(uint8_t cmd) {
+  digitalWrite(CYD_TOUCH_CS, LOW);
+  soft_write(cmd);
+  uint16_t v = soft_read12();
+  digitalWrite(CYD_TOUCH_CS, HIGH);
+  return v;
+}
+
+static int16_t clampi(int32_t v, int32_t lo, int32_t hi) {
+  if (v < lo) {
+    return (int16_t)lo;
+  }
+  if (v > hi) {
+    return (int16_t)hi;
+  }
+  return (int16_t)v;
+}
+
+void touch_init() {
+  pinMode(CYD_TOUCH_CS, OUTPUT);
+  pinMode(CYD_TOUCH_CLK, OUTPUT);
+  pinMode(CYD_TOUCH_MOSI, OUTPUT);
+  pinMode(CYD_TOUCH_MISO, INPUT);
+  pinMode(CYD_TOUCH_IRQ, INPUT);
+  digitalWrite(CYD_TOUCH_CS, HIGH);
+  digitalWrite(CYD_TOUCH_CLK, LOW);
+  Serial.println("Touch: SoftSPI + diagonal fix (BL/TR)");
+}
+
+void touch_read_cb(lv_indev_t * /*indev*/, lv_indev_data_t *data) {
+  uint16_t adc_x = xpt_read(0x90);
+  uint16_t adc_y = xpt_read(0xD0);
+  adc_x = (uint16_t)((adc_x + xpt_read(0x90)) / 2);
+  adc_y = (uint16_t)((adc_y + xpt_read(0xD0)) / 2);
+
+  const bool irq = (digitalRead(CYD_TOUCH_IRQ) == LOW);
+  const bool in_range =
+      (adc_x > 80 && adc_x < 4000 && adc_y > 80 && adc_y < 4000);
+
+  if (!in_range || (!irq && (adc_x < 200 || adc_y < 200))) {
+    data->state = LV_INDEV_STATE_RELEASED;
+    g_dbg_touch_down = false;
+    return;
+  }
+
+  const int16_t p_x = (int16_t)adc_x;
+  const int16_t p_y = (int16_t)(4095 - adc_y);
+
+  int16_t x = map(p_x, 200, 3700, 1, SCREEN_WIDTH);
+  int16_t y = map(p_y, 240, 3800, 1, SCREEN_HEIGHT);
+  x = clampi(x, 0, SCREEN_WIDTH - 1);
+  y = clampi(y, 0, SCREEN_HEIGHT - 1);
+
+  // 旧 UI（LVGL270）：(y, 239-x) — 该空间里 BL↔TR，做主对角线镜像
+  // (ux,uy) -> (uy*(319/239), ux*(239/319))
+  const int32_t old_ux = y;
+  const int32_t old_uy = (SCREEN_WIDTH - 1) - x;
+  int16_t ui_x = clampi((old_uy * (UI_HOR_RES - 1)) / (UI_VER_RES - 1), 0,
+                        UI_HOR_RES - 1);
+  int16_t ui_y = clampi((old_ux * (UI_VER_RES - 1)) / (UI_HOR_RES - 1), 0,
+                        UI_VER_RES - 1);
+
+  // 反变换喂 LVGL，使最终落在 (ui_x, ui_y)
+  const int16_t feed_x = (int16_t)((SCREEN_WIDTH - 1) - ui_y);
+  const int16_t feed_y = ui_x;
+
+  g_dbg_phys_x = x;
+  g_dbg_phys_y = y;
+  g_dbg_logic_x = ui_x;
+  g_dbg_logic_y = ui_y;
+  g_dbg_touch_down = true;
+
+  static uint32_t last_log = 0;
+  if (millis() - last_log > 80) {
+    last_log = millis();
+    Serial.printf("Touch UI(%d,%d)\n", ui_x, ui_y);
+  }
+
+  data->point.x = feed_x;
+  data->point.y = feed_y;
+  data->state = LV_INDEV_STATE_PRESSED;
+}

src/ui.cpp

@@ -0,0 +1,184 @@
+#include "ui.h"
+#include "lcd.h"
+#include "pins.h"
+
+#include <Arduino.h>
+#include <lvgl.h>
+#include <stdio.h>
+
+static constexpr uint32_t COL_BG = 0x0A1016;
+static constexpr uint32_t COL_INK = 0xEAF0F6;
+static constexpr uint32_t COL_MUTED = 0x7A8B9C;
+static constexpr uint32_t COL_BTN = 0x243140;
+static constexpr uint32_t COL_ON = 0x1B5E4A;
+static constexpr uint32_t COL_ACCENT = 0x7CDBFF;
+static constexpr uint32_t COL_DIM = 0x3A4656;
+static constexpr uint32_t COL_ERR = 0xC62828;
+
+static lv_obj_t *lbl_title;
+static lv_obj_t *lbl_pin;
+static lv_obj_t *lbl_status;
+static lv_obj_t *lbl_line0;
+static lv_obj_t *lbl_line1;
+static lv_obj_t *btn_demo;
+static lv_obj_t *lbl_demo;
+static lv_obj_t *btn_hello;
+static lv_obj_t *btn_clear;
+static lv_obj_t *btn_bl;
+static lv_obj_t *lbl_bl;
+
+static uint8_t g_demo_idx = 0;
+
+static void style_btn(lv_obj_t *btn, uint32_t bg) {
+  lv_obj_set_style_radius(btn, 10, 0);
+  lv_obj_set_style_bg_color(btn, lv_color_hex(bg), 0);
+  lv_obj_set_style_bg_opa(btn, LV_OPA_COVER, 0);
+  lv_obj_set_style_shadow_width(btn, 0, 0);
+  lv_obj_set_style_border_width(btn, 0, 0);
+  lv_obj_set_style_pad_all(btn, 0, 0);
+}
+
+static lv_obj_t *make_btn(lv_obj_t *parent, const char *txt, int16_t x,
+                          int16_t y, int16_t w, int16_t h, lv_event_cb_t cb,
+                          lv_obj_t **out_lbl) {
+  lv_obj_t *btn = lv_button_create(parent);
+  lv_obj_set_size(btn, w, h);
+  lv_obj_align(btn, LV_ALIGN_TOP_LEFT, x, y);
+  style_btn(btn, COL_BTN);
+  lv_obj_add_event_cb(btn, cb, LV_EVENT_CLICKED, nullptr);
+  lv_obj_t *lbl = lv_label_create(btn);
+  lv_label_set_text(lbl, txt);
+  lv_obj_set_style_text_color(lbl, lv_color_hex(COL_INK), 0);
+  lv_obj_set_style_text_font(lbl, &lv_font_montserrat_16, 0);
+  lv_obj_center(lbl);
+  if (out_lbl) {
+    *out_lbl = lbl;
+  }
+  return btn;
+}
+
+void ui_refresh_lcd() {
+  char l0[LCD_COLS + 1];
+  char l1[LCD_COLS + 1];
+  lcd_get_line(0, l0, sizeof(l0));
+  lcd_get_line(1, l1, sizeof(l1));
+
+  if (lbl_line0) {
+    lv_label_set_text_fmt(lbl_line0, "[%s]", l0);
+  }
+  if (lbl_line1) {
+    lv_label_set_text_fmt(lbl_line1, "[%s]", l1);
+  }
+
+  if (lbl_status) {
+    if (lcd_ok()) {
+      lv_label_set_text_fmt(lbl_status, "OK  addr 0x%02X", lcd_addr());
+      lv_obj_set_style_text_color(lbl_status, lv_color_hex(COL_ON), 0);
+    } else {
+      lv_label_set_text(lbl_status, "FAIL  no PCF8574");
+      lv_obj_set_style_text_color(lbl_status, lv_color_hex(COL_ERR), 0);
+    }
+  }
+
+  if (lbl_bl) {
+    lv_label_set_text(lbl_bl, lcd_backlight() ? "BL OFF" : "BL ON");
+  }
+  if (btn_bl) {
+    style_btn(btn_bl, lcd_backlight() ? COL_ON : COL_DIM);
+  }
+  if (lbl_demo) {
+    lv_label_set_text_fmt(lbl_demo, "Demo %u/%u",
+                          (unsigned)(g_demo_idx % lcd_demo_count() + 1),
+                          (unsigned)lcd_demo_count());
+  }
+}
+
+static void on_demo(lv_event_t *e) {
+  if (lv_event_get_code(e) != LV_EVENT_CLICKED) {
+    return;
+  }
+  lcd_demo(g_demo_idx);
+  g_demo_idx = (uint8_t)((g_demo_idx + 1) % lcd_demo_count());
+  ui_refresh_lcd();
+}
+
+static void on_hello(lv_event_t *e) {
+  if (lv_event_get_code(e) != LV_EVENT_CLICKED) {
+    return;
+  }
+  lcd_set_backlight(true);
+  lcd_set_line(0, "Hello World!");
+  lcd_set_line(1, "LCD1602A");
+  ui_refresh_lcd();
+}
+
+static void on_clear(lv_event_t *e) {
+  if (lv_event_get_code(e) != LV_EVENT_CLICKED) {
+    return;
+  }
+  lcd_clear();
+  ui_refresh_lcd();
+}
+
+static void on_bl(lv_event_t *e) {
+  if (lv_event_get_code(e) != LV_EVENT_CLICKED) {
+    return;
+  }
+  lcd_set_backlight(!lcd_backlight());
+  ui_refresh_lcd();
+}
+
+void ui_create() {
+  lv_obj_t *scr = lv_screen_active();
+  lv_obj_set_style_bg_color(scr, lv_color_hex(COL_BG), 0);
+  lv_obj_set_style_bg_opa(scr, LV_OPA_COVER, 0);
+
+  lbl_title = lv_label_create(scr);
+  lv_label_set_text(lbl_title, "LCD1602A");
+  lv_obj_set_style_text_color(lbl_title, lv_color_hex(COL_INK), 0);
+  lv_obj_set_style_text_font(lbl_title, &lv_font_montserrat_28, 0);
+  lv_obj_align(lbl_title, LV_ALIGN_TOP_MID, 0, 4);
+
+  lbl_pin = lv_label_create(scr);
+  lv_label_set_text_fmt(lbl_pin, "I2C  SDA%d  SCL%d  PCF8574", LCD_I2C_SDA_PIN,
+                        LCD_I2C_SCL_PIN);
+  lv_obj_set_style_text_color(lbl_pin, lv_color_hex(COL_MUTED), 0);
+  lv_obj_set_style_text_font(lbl_pin, &lv_font_montserrat_14, 0);
+  lv_obj_align(lbl_pin, LV_ALIGN_TOP_MID, 0, 36);
+
+  lbl_status = lv_label_create(scr);
+  lv_label_set_text(lbl_status, "...");
+  lv_obj_set_style_text_font(lbl_status, &lv_font_montserrat_14, 0);
+  lv_obj_align(lbl_status, LV_ALIGN_TOP_MID, 0, 54);
+
+  lbl_line0 = lv_label_create(scr);
+  lv_label_set_text(lbl_line0, "[                ]");
+  lv_obj_set_style_text_color(lbl_line0, lv_color_hex(COL_ACCENT), 0);
+  lv_obj_set_style_text_font(lbl_line0, &lv_font_montserrat_18, 0);
+  lv_obj_align(lbl_line0, LV_ALIGN_TOP_MID, 0, 78);
+
+  lbl_line1 = lv_label_create(scr);
+  lv_label_set_text(lbl_line1, "[                ]");
+  lv_obj_set_style_text_color(lbl_line1, lv_color_hex(COL_ACCENT), 0);
+  lv_obj_set_style_text_font(lbl_line1, &lv_font_montserrat_18, 0);
+  lv_obj_align(lbl_line1, LV_ALIGN_TOP_MID, 0, 104);
+
+  const int16_t gap = 8;
+  const int16_t bw = (UI_HOR_RES - 48 - gap) / 2;
+  const int16_t bx0 = 24;
+  const int16_t row0 = 140;
+  const int16_t row1 = 188;
+
+  btn_demo = make_btn(scr, "Demo", bx0, row0, bw, 40, on_demo, &lbl_demo);
+  btn_hello = make_btn(scr, "Hello", bx0 + bw + gap, row0, bw, 40, on_hello,
+                       nullptr);
+  btn_clear =
+      make_btn(scr, "Clear", bx0, row1, bw, 40, on_clear, nullptr);
+  btn_bl = make_btn(scr, "BL OFF", bx0 + bw + gap, row1, bw, 40, on_bl, &lbl_bl);
+
+  (void)btn_demo;
+  (void)btn_hello;
+  (void)btn_clear;
+
+  ui_refresh_lcd();
+}