feat(led): drive VFD digits via vfdservice pipe (TITLE/CLOCK), keep display API

lib/led.js

@@ -13,15 +13,71 @@ const { hasLanCableCarrier } = require('./network');
  *   alarm → pwr（SETUP=灭 / APPS=亮）
  *   BT    → 无 sysfs，仅日志
  *
- * 数码管（AP/Conn/时间等）：仍仅 debug 输出，不接 sysfs。
+ * 数码管：vfdservice 管道（660 字节，mode=4 TITLE / mode=1 CLOCK，与板端 Demo 一致）。
+ * CLAWD_VFD_PIPE 默认 /tmp/openvfd_service；管道不存在时仅 debug，不抛错。
  *
- * CLAWD_OPENVFD_PATH 默认 /sys/class/leds/openvfd
+ * CLAWD_OPENVFD_PATH 默认 /sys/class/leds/openvfd（图标灯）
  */
 
 const BLINK_INTERVAL_MS = 500;
 const LAN_POLL_MS       = 500;
 
 const VFD_BASE = process.env.CLAWD_OPENVFD_PATH || '/sys/class/leds/openvfd';
+const VFD_PIPE = process.env.CLAWD_VFD_PIPE || '/tmp/openvfd_service';
+const VFD_BUF_SIZE   = 660;
+const VFD_MODE_CLOCK = 1;
+const VFD_MODE_TITLE = 4;
+const VFD_TITLE_OFF  = 20;
+
+function vfdPipePresent() {
+  try {
+    return fs.existsSync(VFD_PIPE);
+  } catch (_) {
+    return false;
+  }
+}
+
+/** TITLE：固定 4 字符，ASCII，供 vfdservice 解析为段码 */
+function vfdTitleNormalize(raw) {
+  return String(raw || '')
+    .toUpperCase()
+    .replace(/[^A-Z0-9 \-]/g, ' ')
+    .slice(0, 4)
+    .padEnd(4, ' ');
+}
+
+function writeVfdPipeTitle(text4) {
+  if (!vfdPipePresent()) return;
+  const seg = vfdTitleNormalize(text4);
+  const data = Buffer.alloc(VFD_BUF_SIZE);
+  data.writeUInt16LE(VFD_MODE_TITLE, 0);
+  try {
+    data.write(`${seg}\0`, VFD_TITLE_OFF, 'ascii');
+  } catch (e) {
+    log.debug('display', `openvfd title encode: ${e.message}`);
+    return;
+  }
+  try {
+    const fd = fs.openSync(VFD_PIPE, 'w');
+    fs.writeSync(fd, data);
+    fs.closeSync(fd);
+  } catch (e) {
+    log.debug('display', `openvfd pipe title: ${e.message}`);
+  }
+}
+
+function writeVfdPipeClock() {
+  if (!vfdPipePresent()) return;
+  const data = Buffer.alloc(VFD_BUF_SIZE);
+  data.writeUInt16LE(VFD_MODE_CLOCK, 0);
+  try {
+    const fd = fs.openSync(VFD_PIPE, 'w');
+    fs.writeSync(fd, data);
+    fs.closeSync(fd);
+  } catch (e) {
+    log.debug('display', `openvfd pipe clock: ${e.message}`);
+  }
+}
 
 function vfdOn(icon) {
   try {
@@ -166,18 +222,18 @@ class Display {
 
   showAP() {
     this._stopBlink();
-    this._write('#m3AP  ');
+    this._pipeTitle('AP  ', '#m3AP  ');
     log.info('display', '显示屏 → AP');
   }
 
   showConn() {
     this._stopBlink();
-    this._write('#m3Conn');
+    this._pipeTitle('Conn', '#m3Conn');
     log.info('display', '显示屏 → Conn（闪烁）');
     let visible = true;
     const blink = () => {
       visible = !visible;
-      this._write(visible ? '#m3Conn' : '#c1');
+      this._pipeTitle(visible ? 'Conn' : '    ', visible ? '#m3Conn' : '#c1');
       this._blinkTimer = setTimeout(blink, visible ? 1000 : 500);
     };
     this._blinkTimer = setTimeout(blink, 1000);
@@ -185,25 +241,26 @@ class Display {
 
   showErr0() {
     this._stopBlink();
-    this._write('#m3Err0');
+    this._pipeTitle('Err0', '#m3Err0');
     log.info('display', '显示屏 → Err0');
   }
 
   showTime() {
     this._stopBlink();
-    this._write('#s1');
+    log.debug('display', '[vfd] #s1');
+    writeVfdPipeClock();
     log.info('display', '显示屏 → 时间');
   }
 
   showPin(pin) {
     this._stopBlink();
     const s = String(pin || '').padStart(4, '0').slice(-4);
-    this._write('#m2' + s);
+    this._pipeTitle(s, '#m2' + s);
     log.info('display', `显示屏 → PIN: ${s}（闪烁）`);
     let visible = true;
     const blink = () => {
       visible = !visible;
-      this._write(visible ? '#m2' + s : '#c1');
+      this._pipeTitle(visible ? s : '    ', visible ? '#m2' + s : '#c1');
       this._blinkTimer = setTimeout(blink, visible ? 1000 : 500);
     };
     this._blinkTimer = setTimeout(blink, 1000);
@@ -217,8 +274,10 @@ class Display {
     }
   }
 
-  _write(val) {
-    log.debug('display', `[vfd] ${val}`);
+  /** 保留原 #m3/#m2/#c1 的 debug 语义，并写 vfdservice TITLE */
+  _pipeTitle(fourCharText, debugLegacy) {
+    log.debug('display', `[vfd] ${debugLegacy}`);
+    writeVfdPipeTitle(fourCharText);
   }
 }