From 70bff5c1285df6da24b8fc15dd8ef52c2775ee54 Mon Sep 17 00:00:00 2001
From: UnKnoWn-Consortium <UnKnoWn-Consortium@users.noreply.github.com>
Date: Sun, 25 Jan 2015 00:04:30 +0000
Subject: [PATCH] Update ChangeUID.ino

Updated code to account for serial behavior change in ATMEGA32U4
---
 examples/ChangeUID/ChangeUID.ino | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/examples/ChangeUID/ChangeUID.ino b/examples/ChangeUID/ChangeUID.ino
index aa3f53b..0a0a2ff 100644
--- a/examples/ChangeUID/ChangeUID.ino
+++ b/examples/ChangeUID/ChangeUID.ino
@@ -51,7 +51,8 @@ MFRC522::MIFARE_Key key;
 
 void setup() {
         Serial.begin(9600);        // Initialize serial communications with the PC
-        SPI.begin();                // Init SPI bus
+        while (!Serial);           // Do nothing if no serial port is opened (added for Arduinos based on ATMEGA32U4)
+        SPI.begin();               // Init SPI bus
         mfrc522.PCD_Init();        // Init MFRC522 card
         Serial.println("Warning: this example overwrites the UID of your UID changeable card, use with care!");