From 5a338ef2b35284f4b3b41fa9fd69b25dd749608b Mon Sep 17 00:00:00 2001
From: Matt Hillsdon <matt.hillsdon@microbit.org>
Date: Wed, 28 Sep 2022 16:05:58 +0100
Subject: [PATCH 1/3] Stop the oscillator on board stop.

Otherwise music.pitch plays forever until you stop it with code.
---
 src/board/audio/index.ts | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/board/audio/index.ts b/src/board/audio/index.ts
index 92fac218..7070ea18 100644
--- a/src/board/audio/index.ts
+++ b/src/board/audio/index.ts
@@ -138,7 +138,9 @@ export class Audio {
     }
   }
 
-  boardStopped() {}
+  boardStopped() {
+    this.oscillator?.stop();
+  }
 }
 
 class BufferedAudio {

From 09d8c8423f562f6228c59925ebec506fc68541d6 Mon Sep 17 00:00:00 2001
From: Matt Hillsdon <matt.hillsdon@microbit.org>
Date: Wed, 28 Sep 2022 16:10:24 +0100
Subject: [PATCH 2/3] Share code with setAmplitudeU10.

Stop and clear the field in both cases.
---
 src/board/audio/index.ts | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/board/audio/index.ts b/src/board/audio/index.ts
index 7070ea18..eb26f470 100644
--- a/src/board/audio/index.ts
+++ b/src/board/audio/index.ts
@@ -125,10 +125,7 @@ export class Audio {
   }
 
   setAmplitudeU10(amplitudeU10: number) {
-    if (this.oscillator) {
-      this.oscillator.stop();
-      this.oscillator = undefined;
-    }
+    this.stopOscillator();
     if (amplitudeU10) {
       this.oscillator = this.context!.createOscillator();
       this.oscillator.type = "sine";
@@ -139,7 +136,14 @@ export class Audio {
   }
 
   boardStopped() {
-    this.oscillator?.stop();
+    this.stopOscillator();
+  }
+
+  private stopOscillator() {
+    if (this.oscillator) {
+      this.oscillator.stop();
+      this.oscillator = undefined;
+    }
   }
 }
 

From 18da8faecf476faf41e19e60a0380a329570804b Mon Sep 17 00:00:00 2001
From: Matt Hillsdon <matt.hillsdon@microbit.org>
Date: Wed, 28 Sep 2022 16:40:26 +0100
Subject: [PATCH 3/3] Avoid divide by zero in the same way as CODAL.

---
 src/board/audio/index.ts | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/board/audio/index.ts b/src/board/audio/index.ts
index eb26f470..1c46fd99 100644
--- a/src/board/audio/index.ts
+++ b/src/board/audio/index.ts
@@ -118,7 +118,8 @@ export class Audio {
   }
 
   setPeriodUs(periodUs: number) {
-    this.frequency = 1000000 / periodUs;
+    // CODAL defaults in this way:
+    this.frequency = periodUs === 0 ? 6068 : 1000000 / periodUs;
     if (this.oscillator) {
       this.oscillator.frequency.value = this.frequency;
     }