From 2ac1fa89a996c9b4e65912c77346f1384012af5d Mon Sep 17 00:00:00 2001
From: Kees Bakker <kees@sodaq.com>
Date: Fri, 8 Dec 2017 21:07:16 +0100
Subject: [PATCH] Avoid read-modify-write when enabling SERCOM DRE interrupt

---
 cores/arduino/SERCOM.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cores/arduino/SERCOM.cpp b/cores/arduino/SERCOM.cpp
index 42c46d015..200c6cda1 100644
--- a/cores/arduino/SERCOM.cpp
+++ b/cores/arduino/SERCOM.cpp
@@ -175,7 +175,7 @@ int SERCOM::writeDataUART(uint8_t data)
 
 void SERCOM::enableDataRegisterEmptyInterruptUART()
 {
-  sercom->USART.INTENSET.reg |= SERCOM_USART_INTENSET_DRE;
+  sercom->USART.INTENSET.reg = SERCOM_USART_INTENSET_DRE;
 }
 
 void SERCOM::disableDataRegisterEmptyInterruptUART()