From d7f384f680479ab3e901196395d2ebf9bb584117 Mon Sep 17 00:00:00 2001
From: Brendan-csel <brendan@csel.co.nz>
Date: Mon, 29 Jul 2013 21:00:29 +1200
Subject: [PATCH] Skip SD menu refresh if nothing has changed

---
 Marlin/ultralcd.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Marlin/ultralcd.cpp b/Marlin/ultralcd.cpp
index 25ed3ef9c..bb9842178 100644
--- a/Marlin/ultralcd.cpp
+++ b/Marlin/ultralcd.cpp
@@ -695,6 +695,8 @@ static void lcd_sd_updir()
 
 void lcd_sdcard_menu()
 {
+    if (lcdDrawUpdate == 0 && LCD_CLICKED == 0) 
+        return;	// nothing to do (so don't thrash the SD card)
     uint16_t fileCnt = card.getnrfilenames();
     START_MENU();
     MENU_ITEM(back, MSG_MAIN, lcd_main_menu);