fixed most upload issues, updated schematic

app/app.js

@@ -1,6 +1,6 @@
 // app.js — UI glue for the BabyMobile manager PWA.
 import { BabyMobile, isSupported, MAX_TRACKS } from './ble.js';
-import { fileToWav, RATES, BITS } from './wav.js';
+import { decodeFileToMono, encodeWav, trimSamples, RATES, BITS } from './wav.js';
 
 const $ = (id) => document.getElementById(id);
 const dev = new BabyMobile();
@@ -12,6 +12,8 @@ let slots = loadSlots();
 
 let pendingWav = null;     // { wav, durationSec, rate, bits, name }
 let deviceTracks = null;   // last result of dev.listTracks(), or null
+let currentFile = null;    // the picked File
+let decoded = null;        // { samples, rate, srcRate } cached decode of currentFile
 
 function loadSlots() {
   try { return JSON.parse(localStorage.getItem(SLOTS_KEY)) || {}; }
@@ -67,35 +69,93 @@ $('drop').addEventListener('drop', (e) => {
 });
 fileInput.addEventListener('change', () => { if (fileInput.files.length) handleFile(fileInput.files[0]); });
 
+// Decode the file (expensive) once per file/rate, then re-encode cheaply when
+// the user tweaks bit-depth or trim.
 async function handleFile(file) {
-  const rate = parseInt($('rate').value, 10);
+  stopPreview();
-  const bits = parseInt($('bits').value, 10);
+  currentFile = file;
-  $('convert-info').textContent = `Converting "${file.name}"…`;
+  decoded = null;
   pendingWav = null;
   $('btn-upload').disabled = true;
+  $('btn-preview').disabled = true;
+  $('trim').hidden = true;
+  $('convert-info').textContent = `Decoding "${file.name}"…`;
   try {
-    const res = await fileToWav(file, { rate, bits });
+    const rate = parseInt($('rate').value, 10);
-    pendingWav = { ...res, name: file.name };
+    decoded = await decodeFileToMono(file, rate);
-    const sec = res.durationSec.toFixed(1);
+    $('trim-start').value = '0';
-    $('convert-info').innerHTML =
+    $('trim-end').value = '0';
-      `<b>${file.name}</b> → ${bits}-bit ${rate / 1000} kHz mono<br>` +
+    $('trim').hidden = false;
-      `${sec}s · ${fmtBytes(res.wav.byteLength)} (incl. 44-byte WAV header)`;
+    reEncode();
-    $('btn-upload').disabled = !dev.connected;
   } catch (err) {
     $('convert-info').textContent = 'Could not decode this file: ' + (err.message || err) +
       '. Try a WAV/MP3/M4A the browser can decode.';
   }
 }
 
-// Re-convert if the format options change while a file is staged.
+function trimValues() {
-['rate', 'bits'].forEach((id) => $(id).addEventListener('change', () => {
+  return {
-  if (fileInput.files.length) handleFile(fileInput.files[0]);
+    trimStart: Math.max(0, parseFloat($('trim-start').value) || 0),
-}));
+    trimEnd: Math.max(0, parseFloat($('trim-end').value) || 0),
+  };
+}
+
+// Re-encode the staged WAV from the cached decode (no re-decode).
+function reEncode() {
+  if (!decoded || !currentFile) return;
+  const bits = parseInt($('bits').value, 10);
+  const { trimStart, trimEnd } = trimValues();
+  const fullDur = decoded.samples.length / decoded.rate;
+  const { wav, durationSec } = encodeWav(decoded.samples, decoded.rate, bits, { trimStart, trimEnd });
+  pendingWav = { wav, durationSec, rate: decoded.rate, bits, name: currentFile.name };
+
+  const trimmed = (trimStart || trimEnd) ? ` (trimmed from ${fullDur.toFixed(1)}s)` : '';
+  $('convert-info').innerHTML =
+    `<b>${currentFile.name}</b> → ${bits}-bit ${decoded.rate / 1000} kHz mono<br>` +
+    `${durationSec.toFixed(1)}s${trimmed} · ${fmtBytes(wav.byteLength)} (incl. 44-byte WAV header)`;
+  $('btn-upload').disabled = !dev.connected || durationSec <= 0;
+  $('btn-preview').disabled = durationSec <= 0;
+}
+
+// Changing the rate needs a fresh decode; bits/trim only need a re-encode.
+$('rate').addEventListener('change', () => { if (currentFile) handleFile(currentFile); });
+['bits', 'trim-start', 'trim-end'].forEach((id) => $(id).addEventListener('input', () => { stopPreview(); reEncode(); }));
+
+// ---- local preview of the trimmed clip ----
+let previewCtx = null;
+let previewSrc = null;
+function stopPreview() {
+  if (previewSrc) { try { previewSrc.stop(); } catch {} previewSrc = null; }
+  if (previewCtx) { try { previewCtx.close(); } catch {} previewCtx = null; }
+  $('btn-preview').textContent = '▶ Preview';
+}
+$('btn-preview').addEventListener('click', () => {
+  if (previewSrc) { stopPreview(); return; }
+  if (!decoded) return;
+  const { trimStart, trimEnd } = trimValues();
+  const slice = trimSamples(decoded.samples, decoded.rate, trimStart, trimEnd);
+  if (!slice.length) return;
+  const AC = window.AudioContext || window.webkitAudioContext;
+  previewCtx = new AC();
+  const buf = previewCtx.createBuffer(1, slice.length, decoded.rate);
+  buf.getChannelData(0).set(slice);
+  previewSrc = previewCtx.createBufferSource();
+  previewSrc.buffer = buf;
+  previewSrc.connect(previewCtx.destination);
+  previewSrc.onended = stopPreview;
+  previewSrc.start();
+  $('btn-preview').textContent = '⏹ Stop';
+});
 
 // ---- upload ----
 $('btn-upload').addEventListener('click', async () => {
   if (!pendingWav) return;
   const track = parseInt($('upload-slot').value, 10);
+  if (occupiedSlots().has(track)) {
+    const name = slots[track]?.name;
+    if (!confirm(`Slot ${track} already holds ${name ? `"${name}"` : 'a track'}. Overwrite it?`)) return;
+  }
+  stopPreview();
   $('btn-upload').disabled = true;
   const bar = $('upload-bar');
   bar.style.width = '0%';
@@ -120,10 +180,6 @@ $('btn-upload').addEventListener('click', async () => {
   }
 });
 
-// ---- playback ----
-$('btn-play').addEventListener('click', () => dev.play(parseInt($('play-slot').value, 10)).catch((e) => log('' + e)));
-$('btn-stop').addEventListener('click', () => dev.stop().catch((e) => log('' + e)));
-
 // ---- track list ----
 $('btn-refresh').addEventListener('click', () => refresh());
 
@@ -138,8 +194,10 @@ async function refresh() {
   }
 }
 
-async function onDelete(idx, onDevice) {
+async function onDelete(idx, onDevice, name) {
+  const label = name ? `"${name}"` : `the track in slot ${idx}`;
   if (onDevice) {
+    if (!confirm(`Delete ${label} from the device? This can't be undone.`)) return;
     try {
       const r = await dev.deleteTrack(idx);
       if (r.success) {
@@ -153,6 +211,7 @@ async function onDelete(idx, onDevice) {
       log('Delete failed: ' + (err.message || err));
     }
   } else {
+    if (!confirm(`Forget ${label} from this browser's list? (It only clears the local record.)`)) return;
     delete slots[idx]; saveSlots(); renderSlots();
   }
 }
@@ -171,6 +230,8 @@ function renderSlots() {
         durationSec: slots[k].durationSec, name: slots[k].name,
       }));
 
+  updateUploadSlotOptions(); // keep the upload picker's "next free" in sync
+
   if (!rows.length) {
     list.innerHTML = `<li class="empty">${onDevice ? 'No tracks on the device yet.' : 'Connect to list device tracks.'}</li>`;
     return;
@@ -185,11 +246,12 @@ function renderSlots() {
     const actions = document.createElement('div');
     actions.className = 'slot-actions';
     const playBtn = btn('▶', 'Play', () => dev.play(t.idx).catch((e) => log('' + e)));
-    playBtn.dataset.needsConn = '';
+    const stopBtn = btn('⏹', 'Stop', () => dev.stop().catch((e) => log('' + e)));
-    playBtn.disabled = !dev.connected;
+    playBtn.dataset.needsConn = ''; stopBtn.dataset.needsConn = '';
+    playBtn.disabled = stopBtn.disabled = !dev.connected;
     const delBtn = btn('🗑', onDevice ? 'Delete from device' : 'Forget (local only)',
-      () => onDelete(t.idx, onDevice));
+      () => onDelete(t.idx, onDevice, t.name));
-    actions.append(playBtn, delBtn);
+    actions.append(playBtn, stopBtn, delBtn);
     li.append(actions);
     list.append(li);
   }
@@ -213,9 +275,33 @@ function fillSelect(sel, values, fmt, selected) {
 }
 fillSelect($('rate'), RATES, (v) => `${v / 1000} kHz`, 8000);
 fillSelect($('bits'), BITS, (v) => `${v}-bit`, 8);
-for (const sel of [$('upload-slot'), $('play-slot')]) {
+fillSelect($('play-slot'), Array.from({ length: MAX_TRACKS }, (_, i) => i), (v) => `Slot ${v}`, 0);
-  fillSelect(sel, Array.from({ length: MAX_TRACKS }, (_, i) => i), (v) => `Slot ${v}`, 0);
+
+// Which slots currently hold a track: device truth when connected, else local memory.
+function occupiedSlots() {
+  if (dev.connected && Array.isArray(deviceTracks)) return new Set(deviceTracks.map((t) => t.idx));
+  return new Set(Object.keys(slots).map(Number));
 }
+function nextFreeSlot() {
+  const occ = occupiedSlots();
+  for (let i = 0; i < MAX_TRACKS; i++) if (!occ.has(i)) return i;
+  return MAX_TRACKS - 1; // all full → default to the last slot
+}
+// Rebuild the upload-slot picker, label occupied slots, and default to next free.
+function updateUploadSlotOptions() {
+  const occ = occupiedSlots();
+  const sel = $('upload-slot');
+  sel.innerHTML = '';
+  for (let i = 0; i < MAX_TRACKS; i++) {
+    const o = document.createElement('option');
+    o.value = i;
+    const name = slots[i]?.name;
+    o.textContent = occ.has(i) ? `Slot ${i} — in use${name ? `: ${name}` : ''}` : `Slot ${i} — free`;
+    sel.append(o);
+  }
+  sel.value = String(nextFreeSlot());
+}
+updateUploadSlotOptions();
 
 // ---- support banner ----
 if (!isSupported()) {

app/ble.js

@@ -34,9 +34,9 @@ const TAG_DELETE   = 0xd0;
 
 export const MAX_TRACKS = 32;
 
-// Keep below ATT MTU - 3. The firmware calls configPrphBandwidth(BANDWIDTH_MAX)
+// ATT MTU is negotiated to 247 (firmware requests via requestMtuExchange(247)).
-// so Chrome typically negotiates MTU 247 (244-byte payload). 180 stays well clear.
+// Write-without-response payload = MTU - 3 = 244 bytes.
-const DATA_CHUNK = 180;
+const DATA_CHUNK = 244;
 
 export function isSupported() {
   return typeof navigator !== 'undefined' && !!navigator.bluetooth;
@@ -231,40 +231,60 @@ export class BabyMobile extends EventTarget {
     });
   }
 
-  // Stream a complete WAV file to a slot. `onProgress(sent, total)` is called as
+  // Stream a complete WAV file to a slot. `onProgress(shown, total)` reports a
-  // the firmware acknowledges bytes via the status characteristic.
+  // single monotonic value combining the locally-sent count and the device's
+  // acknowledged count.
   async upload(track, wavBytes, onProgress) {
     this._requireConnected();
     const total = wavBytes.byteLength;
     this._statBytes = 0;
     let acked = 0;
 
-    const progressHandler = (ev) => {
+    // The optimistic local "sent" count races ahead of the device's ack
-      acked = ev.detail.bytes;
+    // notifications, and the two arrive interleaved (and acks can lag badly over
-      if (onProgress) onProgress(Math.min(acked, total), total);
+    // a slow mobile link). Reporting both directly makes the bar jump forward then
+    // snap backward. Clamp to a high-water mark so progress only ever advances.
+    let shown = 0;
+    const report = (n) => {
+      const v = Math.min(Math.max(0, n), total);
+      if (v > shown) { shown = v; if (onProgress) onProgress(shown, total); }
     };
+
+    const progressHandler = (ev) => { acked = ev.detail.bytes; report(acked); };
     this.addEventListener('progress', progressHandler);
 
     try {
       this._log(`Starting upload of ${total} bytes to slot ${track}…`);
       await this._writeCmd([CMD_UPLOAD_START, track & 0xff]);
 
-      // Send all data chunks. Progress is tracked client-side (bytes sent).
+      // Send all data chunks in pipelined batches.  Chrome on Windows serialises
-      // The firmware queues bytes into a ring buffer; actual flash writes happen
+      // individually-awaited writeValueWithoutResponse calls (one Promise per OS
-      // in the background. We do NOT poll per-packet notifications here — that
+      // event loop tick), which limits throughput to ~one packet per ~50 ms and
-      // caused BLE notification-buffer overflow for large files.
+      // turns a 1.4 MB upload into a 6-minute ordeal.  Firing PIPE writes before
-      for (let off = 0; off < total; off += DATA_CHUNK) {
+      // awaiting them all fills multiple BLE connection events per await, saturating
-        const chunk = wavBytes.subarray(off, Math.min(off + DATA_CHUNK, total));
+      // the link.  The firmware's 32 KB ring buffer absorbs bursts comfortably.
-        await this.data.writeValueWithoutResponse(chunk);
+      const PIPE = 6; // packets in flight before each await (~1 KB per batch)
-        if (onProgress) onProgress(off + chunk.length, total);
+      for (let off = 0; off < total; off += DATA_CHUNK * PIPE) {
+        const batch = [];
+        for (let i = 0; i < PIPE && off + i * DATA_CHUNK < total; i++) {
+          const s = off + i * DATA_CHUNK;
+          batch.push(this.data.writeValueWithoutResponse(
+            wavBytes.subarray(s, Math.min(s + DATA_CHUNK, total))));
+        }
+        await Promise.all(batch);
+        // Cap the optimistic local count at 99%; the final 1% is filled only when
+        // the device's finalize ack confirms the bytes actually landed in flash.
+        report(Math.min(off + DATA_CHUNK * PIPE, Math.floor(total * 0.99)));
       }
 
       // Tell the firmware we're done. It will drain its ring buffer, write the
       // track table, then send ONE finalize notification with the total byte count.
       await this._writeCmd([CMD_UPLOAD_END]);
 
-      // Wait for that single finalize notification (up to 20 s to allow flash writes).
+      // Wait for that single finalize notification.  Allow up to 60 s: at 300 ms/sector
-      await this._waitForAck(total, 20000);
+      // worst-case, a 1.4 MB file has ~350 sectors = 105 s of erase time.  In practice
+      // most sectors erase in ~30 ms so finalization completes in well under 60 s.
+      await this._waitForAck(total, 60000);
       const ok = acked >= total;
       if (ok) {
         this._log(`✅ Upload complete: ${acked}/${total} bytes acknowledged.`);

app/index.html

@@ -13,8 +13,7 @@
 <body>
   <header>
     <div class="brand">
-      <img src="./icon.svg" alt="" width="32" height="32">
+      <img src="./icon.svg" alt="BabyMobile" width="28" height="28">
-      <h1>BabyMobile</h1>
     </div>
     <div class="conn">
       <span id="status-dot" class="dot"></span>
@@ -40,6 +39,11 @@
         <label>Format <select id="bits"></select></label>
         <label>Rate <select id="rate"></select></label>
       </div>
+      <div id="trim" class="opts trim" hidden>
+        <label>Trim start <input id="trim-start" type="number" min="0" step="0.1" value="0"><span class="unit">s</span></label>
+        <label>Trim end <input id="trim-end" type="number" min="0" step="0.1" value="0"><span class="unit">s</span></label>
+        <button id="btn-preview" class="mini" disabled>▶ Preview</button>
+      </div>
       <p id="convert-info" class="info">No file selected.</p>
       <div class="row">
         <label>Upload to <select id="upload-slot" data-needs-conn disabled></select></label>
@@ -48,15 +52,6 @@
       <div class="progress"><div id="upload-bar" class="bar"></div></div>
     </section>
 
-    <section class="card">
-      <h2>2 · Play</h2>
-      <div class="row">
-        <label>Play <select id="play-slot" data-needs-conn disabled></select></label>
-        <button id="btn-play" data-needs-conn disabled>▶ Play</button>
-        <button id="btn-stop" data-needs-conn disabled>⏹ Stop</button>
-      </div>
-    </section>
-
     <section class="card">
       <div class="card-head">
         <h2>Tracks on device</h2>

app/styles.css

@@ -16,6 +16,7 @@ body {
   background: linear-gradient(160deg, var(--bg), var(--bg2));
   color: var(--text);
   min-height: 100vh;
+  overflow-x: hidden;
   -webkit-tap-highlight-color: transparent;
 }
 header {
@@ -48,11 +49,14 @@ button:disabled { opacity: .4; cursor: not-allowed; }
 button.primary { background: linear-gradient(135deg, var(--accent2), var(--accent)); border: none; color: #1a0f3a; font-weight: 600; }
 button.mini { padding: 6px 10px; border-radius: 8px; }
 
-select {
+select, input[type=number] {
   font: inherit; background: #1c123e; color: var(--text);
   border: 1px solid var(--line); border-radius: 8px; padding: 8px 10px;
 }
+input[type=number] { width: 4.5rem; }
 label { display: inline-flex; align-items: center; gap: 8px; font-size: .9rem; color: var(--muted); }
+.trim { align-items: center; }
+.trim .unit { color: var(--muted); margin-left: -4px; }
 
 .drop {
   border: 2px dashed var(--line); border-radius: 14px; padding: 26px 16px;
@@ -87,3 +91,12 @@ label { display: inline-flex; align-items: center; gap: 8px; font-size: .9rem; c
   font-size: .78rem; color: var(--muted); max-height: 200px; overflow: auto; white-space: pre-wrap; margin: 0; }
 footer { text-align: center; color: var(--muted); font-size: .78rem; padding: 8px 16px calc(24px + env(safe-area-inset-bottom)); }
 footer a { color: var(--accent); }
+
+@media (max-width: 480px) {
+  header { padding: 12px 12px calc(12px + env(safe-area-inset-top)); }
+  .conn { gap: 6px; font-size: .8rem; }
+  main { padding: 12px; gap: 12px; }
+  .card { padding: 14px; border-radius: 14px; }
+  .opts { gap: 12px; }
+  .slot-meta b { max-width: 42vw; }
+}

app/sw.js

@@ -1,5 +1,5 @@
 // sw.js — minimal offline cache so the PWA launches without a network.
-const CACHE = 'babymobile-v3';
+const CACHE = 'babymobile-v5';
 const ASSETS = [
   './', './index.html', './styles.css',
   './app.js', './ble.js', './wav.js',

app/wav.js

@@ -72,11 +72,26 @@ function buildWav(pcm, rate, bits) {
   return u8;
 }
 
-// Returns { wav: Uint8Array, durationSec, rate, bits, srcRate }.
+// Decode a file to mono Float32 samples at `rate`. This is the expensive step,
-export async function fileToWav(file, { rate = 8000, bits = 8 } = {}) {
+// so callers cache the result and re-encode cheaply when bits/trim change.
+// Returns { samples, rate, srcRate }.
+export async function decodeFileToMono(file, rate = 8000) {
   const arrayBuffer = await file.arrayBuffer();
   const { samples, srcRate } = await decodeMono(arrayBuffer, rate);
-  const pcm = floatToPcm(samples, bits);
+  return { samples, rate, srcRate };
-  const wav = buildWav(pcm, rate, bits);
+}
-  return { wav, durationSec: samples.length / rate, rate, bits, srcRate };
+
+// Slice [trimStart, end-trimEnd] off the mono samples and return that range.
+export function trimSamples(samples, rate, trimStart = 0, trimEnd = 0) {
+  const start = Math.max(0, Math.min(samples.length, Math.floor(trimStart * rate)));
+  const end = Math.max(start, samples.length - Math.max(0, Math.floor(trimEnd * rate)));
+  return samples.subarray(start, end);
+}
+
+// Encode mono Float32 samples to a WAV. Returns { wav, durationSec }.
+export function encodeWav(samples, rate, bits, { trimStart = 0, trimEnd = 0 } = {}) {
+  const sliced = trimSamples(samples, rate, trimStart, trimEnd);
+  const pcm = floatToPcm(sliced, bits);
+  const wav = buildWav(pcm, rate, bits);
+  return { wav, durationSec: sliced.length / rate };
 }

baby-mobile-v5.kicad_sch

@@ -2872,10 +2872,10 @@
 		(uuid "017eac50-3406-4cc1-bd32-b83e5696234a")
 	)
 	(junction
-		(at 311.16 90.17)
+		(at 71.12 153.67)
 		(diameter 0)
 		(color 0 0 0 0)
-		(uuid "19afce19-eefe-43da-9ff9-594d5e7450df")
+		(uuid "17e89eec-f620-4c7a-8887-8563a7dca664")
 	)
 	(junction
 		(at 330.2 145.97)
@@ -2896,10 +2896,28 @@
 		(uuid "6d7a0476-c2d8-409f-acf0-c51d5cc44c54")
 	)
 	(junction
-		(at 311.16 87.63)
+		(at 309.89 87.63)
 		(diameter 0)
 		(color 0 0 0 0)
-		(uuid "eb2c5735-191b-4d6e-b9b7-6f9a1ba9da7c")
+		(uuid "7f9aeab0-b298-49b0-95a9-13f903c592bd")
+	)
+	(junction
+		(at 311.16 90.17)
+		(diameter 0)
+		(color 0 0 0 0)
+		(uuid "b41da60f-ed92-4caa-94b4-a8f17f7b37f7")
+	)
+	(junction
+		(at 309.88 87.63)
+		(diameter 0)
+		(color 0 0 0 0)
+		(uuid "b4ef88db-519f-48de-b199-16343987ba1f")
+	)
+	(junction
+		(at 67.31 166.37)
+		(diameter 0)
+		(color 0 0 0 0)
+		(uuid "e2984591-bbbd-47a7-b9f3-f6e744a0177d")
 	)
 	(junction
 		(at 207.01 204.47)
@@ -2913,6 +2931,12 @@
 		(color 0 0 0 0)
 		(uuid "ef3a8681-bfa6-40af-9816-ec3346f9cb23")
 	)
+	(junction
+		(at 304.8 87.63)
+		(diameter 0)
+		(color 0 0 0 0)
+		(uuid "fa1bd6ee-5560-42cc-8cc4-182475fa5265")
+	)
 	(no_connect
 		(at 223.52 234.95)
 		(uuid "519c324a-3d40-42a9-a963-f53dd2b596c0")
@@ -2953,6 +2977,16 @@
 		)
 		(uuid "0a315227-f5b7-4de4-9dc2-5a9da0d1e499")
 	)
+	(wire
+		(pts
+			(xy 304.8 91.44) (xy 304.72 91.44)
+		)
+		(stroke
+			(width 0)
+			(type default)
+		)
+		(uuid "0e7e7f7d-d9d1-48e4-b0a4-efa3065d2db0")
+	)
 	(wire
 		(pts
 			(xy 342.9 92.69) (xy 342.9 92.61)
@@ -3005,13 +3039,23 @@
 	)
 	(wire
 		(pts
-			(xy 311.16 87.63) (xy 312.43 87.63)
+			(xy 67.31 166.37) (xy 67.31 171.45)
 		)
 		(stroke
 			(width 0)
 			(type default)
 		)
-		(uuid "24800943-9fa3-42fe-8fc7-e4e93239651c")
+		(uuid "1e67db82-9086-4cc6-acee-2e0c4028091c")
+	)
+	(wire
+		(pts
+			(xy 62.23 166.37) (xy 67.31 166.37)
+		)
+		(stroke
+			(width 0)
+			(type default)
+		)
+		(uuid "1fbb2173-f466-4fb3-a1e1-1fd99f26203e")
 	)
 	(wire
 		(pts
@@ -3053,6 +3097,16 @@
 		)
 		(uuid "33cecf5c-c05b-46be-b395-224afca830f4")
 	)
+	(wire
+		(pts
+			(xy 304.8 87.63) (xy 297.18 87.63)
+		)
+		(stroke
+			(width 0)
+			(type default)
+		)
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baby_mobile_v2/baby_mobile_v2.ino

@@ -183,7 +183,8 @@ BLECharacteristic audioCmd  = BLECharacteristic("12340002-0000-1000-8000-00805f9
 BLECharacteristic audioData = BLECharacteristic("12340003-0000-1000-8000-00805f9b34fb");
 BLECharacteristic audioStat = BLECharacteristic("12340004-0000-1000-8000-00805f9b34fb");
 
-// BLE upload state
+// BLE connection / upload state
+volatile bool     g_bleConnected = false;  // true while a GATT connection is active
 volatile bool     g_bleUploading = false;
 volatile uint32_t g_bleWriteLen  = 0;
 
@@ -192,17 +193,20 @@ File     g_pocFile(InternalFS);   // open file handle (read or write)
 uint8_t  g_pocWriteTrack = 0;     // track slot being written via BLE
 #else
 // Ring buffer between BLE callbacks and loop() flash writes.
-// Callbacks return immediately; flash I/O (especially sector erase ~100ms)
+// Callbacks return immediately; flash I/O happens in loop() so the SoftDevice
-// happens in loop() so the SoftDevice receive buffer never stalls.
+// receive buffer never stalls.  Sector erase is async (non-blocking): bleFlashTick()
-// Size: IS25LP128F sector erase takes up to 300 ms; at ~56 KB/s upload rate
+// kicks off the erase and returns; loop() polls completion each iteration.  This
-// that is ~17 KB of incoming data.  32 KB covers it with margin.
+// prevents the ring buffer from filling during the ~30–300 ms erase window.
-#define BLE_FLASH_BUF 32768u
+// Buffer: 64 KB handles worst-case 300 ms erase at up to ~200 KB/s BLE throughput.
+#define BLE_FLASH_BUF 65536u
 static uint8_t           g_bleBuf[BLE_FLASH_BUF];
 static volatile uint32_t g_bleBufHead    = 0;   // advanced by BLE callback
 static volatile uint32_t g_bleBufTail    = 0;   // advanced by loop()
 static uint32_t          g_bleFlashAddr  = 0;   // current flash write head
 static uint32_t          g_bleFlashStart = 0;   // address where this upload began
-static uint32_t          g_bleFlashErased = 0;  // end of last erased sector
+static uint32_t          g_bleFlashErased = 0;  // upper boundary of erased flash
+static bool              g_bleErasing    = false; // async sector erase in progress
+static uint32_t          g_bleNotifyThresh = 0; // next addr to send progress notify
 static uint8_t           g_bleWriteTrack = 0;
 static volatile bool     g_bleFinalizing = false;
 
@@ -306,6 +310,17 @@ void flashWaitBusy() {
     SPI.endTransaction();
 }
 
+// Non-blocking busy check: reads the WIP bit without spinning.
+bool flashIsBusy() {
+    SPI.beginTransaction(flashSPI);
+    flashSelect();
+    SPI.transfer(CMD_READ_SR1);
+    uint8_t sr = SPI.transfer(0);
+    flashDeselect();
+    SPI.endTransaction();
+    return (sr & 0x01) != 0;
+}
+
 void flashWriteEnable() {
     SPI.beginTransaction(flashSPI);
     flashSelect();
@@ -564,12 +579,26 @@ bool msc_start_stop_cb(uint8_t power_condition, bool start, bool load_eject) {
 
 void ble_connect_cb(uint16_t conn_handle) {
     Serial.println("BLE connected");
+    g_bleConnected = true;
     g_lastActivity = millis();
+
+    // Request fast connection parameters and maximum throughput features.
+    // The central may accept, renegotiate, or ignore these — all safe.
+    BLEConnection* conn = Bluefruit.Connection(conn_handle);
+    if (conn) {
+        conn->requestConnectionParameter(6);  // 6×1.25ms = 7.5ms interval
+        conn->requestMtuExchange(247);         // 244-byte ATT payload
+        conn->requestDataLengthUpdate();       // LE Data Length Extension
+        conn->requestPHY(BLE_GAP_PHY_2MBPS);  // 2M PHY if supported
+    }
 }
 
 void ble_disconnect_cb(uint16_t conn_handle, uint8_t reason) {
     Serial.println("BLE disconnected");
+    g_bleConnected  = false;
     g_bleUploading  = false;
+    g_bleFinalizing = false;
+    g_bleErasing    = false;  // stop tracking the in-progress erase; it will finish in HW
 }
 
 // BLE command characteristic: receives commands
@@ -627,8 +656,10 @@ void audioCmd_write_cb(uint16_t conn_handle, BLECharacteristic* chr,
                 // Track 0 resets allocation; subsequent tracks append
                 if (g_bleWriteTrack == 0) g_flashNextFree = AUDIO_START_ADDR;
                 g_bleFlashAddr    = g_flashNextFree;
-                g_bleFlashStart  = g_bleFlashAddr;  // save start for finalize
+                g_bleFlashStart   = g_bleFlashAddr;
                 g_bleFlashErased  = g_bleFlashAddr;  // nothing erased yet
+                g_bleErasing      = false;
+                g_bleNotifyThresh = g_bleFlashAddr;
                 g_bleBufHead = g_bleBufTail = 0;
                 g_bleFinalizing  = false;
                 g_bleUploading   = true;
@@ -763,37 +794,92 @@ void audioData_write_cb(uint16_t conn_handle, BLECharacteristic* chr,
     // and writes the track table).
 }
 
-// Drain the BLE ring buffer to SPI flash one page at a time.
+// Drain the BLE ring buffer to SPI flash.
-// Called from loop() to keep flash I/O off the BLE callback thread.
+// Sector erases are asynchronous: we issue the erase command and return immediately
+// so loop() keeps running (and the ring buffer keeps draining from BLE callbacks).
+// On the next call we poll the WIP bit to confirm completion before writing.
+// This prevents the 30–300 ms erase window from filling the ring buffer.
+// A pre-erase is also kicked off as soon as we start writing each sector so
+// the next sector is ready before we reach it. Writes stop while any erase is
+// in progress because the flash ignores page-program when WIP=1.
 #ifndef POC_INTERNAL_FLASH
 static void bleFlashTick() {
-    // Drain as much as we can without blocking too long
+    if (!g_bleUploading && !g_bleFinalizing) return;
+
+    // Poll async sector erase completion.
+    if (g_bleErasing && !flashIsBusy()) {
+        g_bleErasing      = false;
+        g_bleFlashErased += FLASH_SECTOR;
+    }
+
+    // Drain all available ring-buffer data into flash, one page per iteration.
     while (g_bleBufHead != g_bleBufTail) {
+        if (g_bleErasing) break;  // never write while an erase is in progress
         uint32_t avail   = (g_bleBufHead - g_bleBufTail + BLE_FLASH_BUF) % BLE_FLASH_BUF;
         uint16_t pageOff = (uint16_t)(g_bleFlashAddr % FLASH_PAGE);
         uint16_t chunk   = (uint16_t)min((uint32_t)(FLASH_PAGE - pageOff), avail);
         if (chunk == 0) break;
 
-        // Lazy erase: erase the next sector just before we write into it
+        if (g_bleFlashAddr + chunk > g_bleFlashErased) {
-        while (g_bleFlashAddr + chunk > g_bleFlashErased) {
+            // Write pointer has reached the erased boundary — need another sector erased.
-            flashEraseSector(g_bleFlashErased);
+            if (!g_bleErasing) {
-            g_bleFlashErased += FLASH_SECTOR;
+                flashWriteEnable();
+                SPI.beginTransaction(flashSPI);
+                flashSelect();
+                SPI.transfer(CMD_SECT_ERASE);
+                SPI.transfer((g_bleFlashErased >> 16) & 0xFF);
+                SPI.transfer((g_bleFlashErased >>  8) & 0xFF);
+                SPI.transfer( g_bleFlashErased        & 0xFF);
+                flashDeselect();
+                SPI.endTransaction();
+                g_bleErasing = true;
+                // Do NOT advance g_bleFlashErased — wait for WIP confirmation next call.
+            }
+            break;  // return to loop(); erase runs in HW, ring buffer fills freely
         }
 
-        // Copy chunk from ring buffer into a temp page buffer
+        // Erase boundary is ahead — safe to program this page.
         uint8_t tmp[FLASH_PAGE];
         for (uint16_t i = 0; i < chunk; i++) {
             tmp[i] = g_bleBuf[(g_bleBufTail + i) % BLE_FLASH_BUF];
         }
-        flashPageProgram(g_bleFlashAddr, tmp, chunk);
+        flashPageProgram(g_bleFlashAddr, tmp, chunk);   // ~0.5 ms blocking
         g_bleBufTail    = (g_bleBufTail + chunk) % BLE_FLASH_BUF;
         g_bleFlashAddr += chunk;
 
-        // Yield after each page so the rest of loop() stays responsive
+        // Pre-erase: kick off the next sector erase as soon as we start writing
-        break;
+        // the current sector so the erase (~30 ms typ) completes before we need it.
+        // Break immediately — never write while an async erase is in progress since
+        // the flash chip silently ignores page-program commands when WIP=1.
+        if (!g_bleErasing && g_bleFlashAddr > g_bleFlashErased - FLASH_SECTOR) {
+            flashWriteEnable();
+            SPI.beginTransaction(flashSPI);
+            flashSelect();
+            SPI.transfer(CMD_SECT_ERASE);
+            SPI.transfer((g_bleFlashErased >> 16) & 0xFF);
+            SPI.transfer((g_bleFlashErased >>  8) & 0xFF);
+            SPI.transfer( g_bleFlashErased        & 0xFF);
+            flashDeselect();
+            SPI.endTransaction();
+            g_bleErasing = true;
+            break;  // wait for erase; ring buffer fills freely in the meantime
         }
 
-    // Finalize when CMD 0x03 received and ring buffer is empty
+        // Periodic progress notification — keeps the Windows BLE stack from
+        // dropping the connection during long silent uploads, and gives the
+        // client real flash-write progress (not just BLE-send progress).
+        if (g_bleConnected && g_bleFlashAddr - g_bleNotifyThresh >= 4096u) {
+            g_bleNotifyThresh = g_bleFlashAddr;
+            uint32_t written = g_bleFlashAddr - g_bleFlashStart;
+            uint8_t stat[4]  = {
+                (uint8_t)(written >> 24), (uint8_t)(written >> 16),
+                (uint8_t)(written >>  8), (uint8_t)(written)
+            };
+            audioStat.notify(stat, 4);
+        }
+    }
+
+    // Finalize when CMD 0x03 received and ring buffer is fully drained.
     if (g_bleFinalizing && g_bleBufHead == g_bleBufTail) {
         uint32_t startAddr   = g_bleFlashStart;
         uint32_t bytesStored = g_bleFlashAddr - g_bleFlashStart;
@@ -806,6 +892,7 @@ static void bleFlashTick() {
 
         g_bleUploading  = false;
         g_bleFinalizing = false;
+        g_bleErasing    = false;  // pre-erase of unused sector, if any, will finish in HW
         writeTrackTable();
         loadTrackTable();
         Serial.printf("BLE: Upload finalized — start=0x%08lX stored=%lu bytes\n", startAddr, bytesStored);
@@ -856,11 +943,15 @@ void setupBLE() {
     audioStat.setMaxLen(4);
     audioStat.begin();
 
-    // Start advertising
+    // Start advertising.
+    // The 128-bit service UUID (18 bytes) plus flags + TxPower nearly fills the
+    // 31-byte advertisement, leaving room for only ~5 name characters — which
+    // truncated the name to "BabyM" over the air. Put the full name in the scan
+    // response (its own separate 31 bytes) so scanners see "BabyMobile" intact.
     Bluefruit.Advertising.addFlags(BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE);
     Bluefruit.Advertising.addTxPower();
     Bluefruit.Advertising.addService(audioSvc);
-    Bluefruit.Advertising.addName();
+    Bluefruit.ScanResponse.addName();   // full name here, not in the ad packet
     Bluefruit.Advertising.restartOnDisconnect(true);
     Bluefruit.Advertising.setInterval(160, 320); // 100-200ms
     Bluefruit.Advertising.start(0);  // advertise forever
@@ -1401,22 +1492,46 @@ static void serUploadTick() {
                     Serial.println("REBOOT");
                     delay(10);
                     NVIC_SystemReset();
-#ifdef POC_INTERNAL_FLASH
-                } else if (sscanf(g_serLineBuf, "DELETE %u", &utrk) == 1) {
-                    char fname[16];
-                    pocFilename((uint8_t)utrk, fname);
-                    if (InternalFS.remove(fname)) {
-                        Serial.print("DELETED "); Serial.println(fname);
-                    } else {
-                        Serial.print("ERR no file "); Serial.println(fname);
-                    }
-                    loadTrackTable();
                 } else if (strcmp(g_serLineBuf, "FORMAT") == 0) {
                     audioStop();
+#ifdef POC_INTERNAL_FLASH
                     Serial.println("Formatting LittleFS...");
                     InternalFS.format();
                     g_numTracks = 0;
+#else
+                    Serial.println("Clearing track table...");
+                    g_numTracks     = 0;
+                    g_flashNextFree = AUDIO_START_ADDR;
+                    writeTrackTable();
+                    loadTrackTable();
+#endif
                     Serial.println("FORMAT OK");
+                } else if (sscanf(g_serLineBuf, "DELETE %u", &utrk) == 1) {
+#ifdef POC_INTERNAL_FLASH
+                    char fname[16];
+                    pocFilename((uint8_t)utrk, fname);
+                    if (InternalFS.remove(fname)) {
+                        Serial.print("DELETED "); Serial.println(utrk);
+                    } else {
+                        Serial.print("ERR no file "); Serial.println(utrk);
+                    }
+                    loadTrackTable();
+#else
+                    if ((uint8_t)utrk < g_numTracks) {
+                        for (uint8_t j = (uint8_t)utrk; j < g_numTracks - 1; j++) {
+                            g_trackStart[j]   = g_trackStart[j+1];
+                            g_trackLen[j]     = g_trackLen[j+1];
+                            g_trackBits[j]    = g_trackBits[j+1];
+                            g_trackRate[j]    = g_trackRate[j+1];
+                            g_trackDataOff[j] = g_trackDataOff[j+1];
+                        }
+                        g_numTracks--;
+                        writeTrackTable();
+                        loadTrackTable();
+                        Serial.print("DELETED "); Serial.println(utrk);
+                    } else {
+                        Serial.print("ERR no track "); Serial.println(utrk);
+                    }
 #endif
                 } else {
                     Serial.print("ERR bad cmd: ");
@@ -1430,6 +1545,7 @@ static void serUploadTick() {
             }
         }
     } else { // SER_RECEIVING
+        g_lastActivity = millis();  // keep device awake during long transfers
         uint8_t chunk[64];
         while (Serial.available() && g_serBytesReceived < g_serBytesExpected) {
             int n = Serial.readBytes(chunk, min((int)sizeof(chunk),
@@ -1498,7 +1614,7 @@ static void serUploadTick() {
 }
 
 void loop() {
-    if (g_playing) g_lastActivity = millis();
+    if (g_playing || g_bleUploading) g_lastActivity = millis();
 
     // ---- Serial upload ----
     serUploadTick();
@@ -1592,14 +1708,18 @@ void loop() {
     }
 
     // ---- Auto shutoff / idle sleep ----
+    // Never sleep while BLE is connected — upload may be in progress or about
+    // to begin, and the CMD callback sets g_bleUploading asynchronously.
+    if (!g_bleConnected) {
         if (millis() - g_lastActivity > AUTO_OFF_MS) {
             enterDeepSleep();
         }
 
-    if (!g_playing && !g_motorOn && !g_usbConnected && !g_bleUploading) {
+        if (!g_playing && !g_motorOn && !g_usbConnected) {
             if (millis() - g_lastActivity > IDLE_SLEEP_MS) {
                 enterDeepSleep();
             }
         }
+    }
 
 }

upload_track.py

@@ -7,9 +7,9 @@ Usage:
 
 Supported formats: .wav, .mp3, .ogg, .flac, .aac, .m4a, .raw (anything ffmpeg handles)
 
-Output format: 16-bit signed PCM WAV, 16 kHz, mono (WAV header included).
+Output format: 8-bit unsigned PCM WAV, 8 kHz, mono (WAV header included).
   - Already-conformant WAV files (PCM, mono, 8 or 16-bit, 8/16/32 kHz) are sent as-is.
-  - All other formats are converted via ffmpeg to 16-bit 16 kHz mono WAV.
+  - All other formats are converted via ffmpeg to 8-bit 8 kHz mono WAV.
   - .raw files are treated as legacy 8-bit unsigned 16 kHz and wrapped in a WAV header.
 
 Requires: pyserial  (pip install pyserial)
@@ -24,7 +24,7 @@ import subprocess
 import serial
 import time
 
-CHUNK_SIZE = 512
+CHUNK_SIZE = 4096
 BAUD_RATE  = 115200
 TIMEOUT_S  = 10.0
 
@@ -92,10 +92,10 @@ def load_wav(path: str) -> bytes:
             f"  ffmpeg -i \"{path}\" -ar 16000 -ac 1 -acodec pcm_s16le out.wav"
         )
 
-    print(f"Converting {os.path.basename(path)} via ffmpeg -> 16-bit 16 kHz mono WAV...")
+    print(f"Converting {os.path.basename(path)} via ffmpeg -> 8-bit 8 kHz mono WAV...")
     result = subprocess.run(
         ['ffmpeg', '-y', '-i', path,
-         '-ar', '16000', '-ac', '1', '-f', 'wav', '-acodec', 'pcm_s16le', 'pipe:1'],
+         '-ar', '8000', '-ac', '1', '-f', 'wav', '-acodec', 'pcm_u8', 'pipe:1'],
         capture_output=True
     )
     if result.returncode != 0:
@@ -141,41 +141,29 @@ def upload(port: str, track_num: int, wav: bytes) -> None:
             if line:
                 print(f"  firmware: {line}")
 
-        # Stream WAV data in chunks; poll for ERR
+        # Stream WAV data without per-chunk polling — the firmware only ever sends
+        # ERR mid-transfer on a flash write failure (very rare); polling after every
+        # chunk adds 50 ms of readline timeout overhead per packet, which for a large
+        # file at USB CDC speeds amounts to many minutes of wasted time.
         sent = 0
-        err_line = None
+        ser.timeout = 0  # non-blocking reads while sending
-        ser.timeout = 0.05
         while sent < total:
             chunk = wav[sent:sent + CHUNK_SIZE]
             ser.write(chunk)
             sent += len(chunk)
             pct = sent * 100 // total
             print(f"\r  {sent}/{total} bytes ({pct}%)   ", end="", flush=True)
-            line = ser.readline().decode(errors="replace").strip()
+            # Drain any early ERR the firmware might have sent
+            line = ser.read(ser.in_waiting).decode(errors="replace").strip()
             if line.startswith("ERR"):
-                err_line = line
+                print()
-                break
+                print(f"ERROR from firmware: {line}")
+                sys.exit(1)
         print()
         ser.timeout = 2.0
 
-        if err_line:
+        # Wait for OK — allow up to 60 s for the final sector erase + flash writes
-            print(f"ERROR from firmware: {err_line}")
+        deadline = time.time() + 60.0
-            if "at=" in err_line:
-                accepted = int(err_line.split("at=")[1].split()[0])
-                safe = int(accepted * 0.9)
-                # estimate audio bytes (subtract header)
-                audio_accepted = max(0, safe - 44)
-                bits = struct.unpack_from('<H', wav, 34)[0] if len(wav) >= 44 else 16
-                rate = struct.unpack_from('<I', wav, 24)[0] if len(wav) >= 44 else 16000
-                max_s = audio_accepted / (bits // 8) / rate
-                print(f"  LittleFS accepted {accepted} bytes before full.")
-                print(f"  Safe clip length: ~{max_s:.1f}s")
-                print(f"  Trim with:  ffmpeg -i input.mp3 -t {max_s:.0f} -ar 16000 -ac 1 "
-                      f"-acodec pcm_s16le out.wav")
-            sys.exit(1)
-
-        # Wait for OK
-        deadline = time.time() + TIMEOUT_S
         while True:
             if time.time() > deadline:
                 sys.exit("Timed out waiting for OK")