From 9b9cd698a5b30036fcb6d643bec114babc8cc7c9 Mon Sep 17 00:00:00 2001
From: Jason Smith <jason.inet@gmail.com>
Date: Fri, 16 Oct 2020 14:04:51 -0700
Subject: [PATCH] Fix SAMD Serial name macro (#19765)

---
 Marlin/src/HAL/SAMD51/HAL.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Marlin/src/HAL/SAMD51/HAL.h b/Marlin/src/HAL/SAMD51/HAL.h
index abc6c04a693..7cb3635bd7c 100644
--- a/Marlin/src/HAL/SAMD51/HAL.h
+++ b/Marlin/src/HAL/SAMD51/HAL.h
@@ -35,7 +35,8 @@
 
   // MYSERIAL0 required before MarlinSerial includes!
 
-  #define _MSERIAL(X) Serial##X
+  #define __MSERIAL(X) Serial##X
+  #define _MSERIAL(X) __MSERIAL(X)
   #define MSERIAL(X) _MSERIAL(INCREMENT(X))
 
   #if SERIAL_PORT == -1