From 3d904994a70c2536ba0bd06b0d3c2f8f9d55a4e9 Mon Sep 17 00:00:00 2001
From: Sandeep Mistry <s.mistry@arduino.cc>
Date: Wed, 14 Feb 2018 11:37:41 -0500
Subject: [PATCH] Make ring buffer head and tail indexes volatile

---
 cores/arduino/RingBuffer.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/cores/arduino/RingBuffer.h b/cores/arduino/RingBuffer.h
index 044df7a46..c92e8633a 100644
--- a/cores/arduino/RingBuffer.h
+++ b/cores/arduino/RingBuffer.h
@@ -34,8 +34,8 @@ class RingBufferN
 {
   public:
     uint8_t _aucBuffer[N] ;
-    int _iHead ;
-    int _iTail ;
+    volatile int _iHead ;
+    volatile int _iTail ;
 
   public:
     RingBufferN( void ) ;