From 6d04e0e0bdce626844b97d5d1e121124f517ac84 Mon Sep 17 00:00:00 2001
From: Peter Feerick <peter.feerick@gmail.com>
Date: Tue, 17 Jan 2017 10:06:15 +1000
Subject: [PATCH] Prevent tone with frequency of '0' from crashing. When tone
 is called specifying a frequency of 0, the code will crash due to a divide by
 zero issue.

---
 cores/oak/Tone.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/cores/oak/Tone.cpp b/cores/oak/Tone.cpp
index dfba490..40d6264 100644
--- a/cores/oak/Tone.cpp
+++ b/cores/oak/Tone.cpp
@@ -66,6 +66,13 @@ void tone(uint8_t _pin, unsigned int frequency, unsigned long duration) {
     // Set the pinMode as OUTPUT
     pinMode(_pin, OUTPUT);
 
+    // Alternate handling of zero freqency to avoid divide by zero errors
+    if (frequency == 0)
+    {
+        noTone(_pin);
+        return;
+    }    
+
     // Calculate the toggle count
     if (duration > 0) {
       toggle_counts[_index] = 2 * frequency * duration / 1000;