From 6736392c3ca4888d50b345da969d8253afd1f776 Mon Sep 17 00:00:00 2001
From: Doc Walker <4-20ma@wvfans.net>
Date: Fri, 22 May 2015 13:19:18 -0500
Subject: [PATCH] Fix #27 Update architecture switch

---
 ModbusMaster.cpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/ModbusMaster.cpp b/ModbusMaster.cpp
index 70fe245..419e8f0 100644
--- a/ModbusMaster.cpp
+++ b/ModbusMaster.cpp
@@ -33,12 +33,12 @@ Arduino library for communicating with Modbus slaves over RS232/485 (via RTU pro
 
 
 /* _____GLOBAL VARIABLES_____________________________________________________ */
-#ifdef __AVR__
+#if defined(ARDUINO_ARCH_AVR)
   HardwareSerial* MBSerial = &Serial; ///< Pointer to Serial class object
-#endif
-
-#ifdef __arm__
+#elif defined(ARDUINO_ARCH_SAM)
   UARTClass* MBSerial = &Serial; ///< Pointer to Serial class object
+#else
+  #error "This library only supports boards with an AVR or SAM processor. Please open an issue at https://github.com/4-20ma/ModbusMaster/issues and indicate which processor/platform you're using."
 #endif