From 56c02b7f59bc83da78ef04e1065b1f5c9fe49dc1 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <github@thinkyhead.com>
Date: Tue, 21 Nov 2017 00:20:01 -0600
Subject: [PATCH] Shift register buttons question

Can LCD shift registers keep up with faster MCUs?
---
 Marlin/src/lcd/ultralcd.cpp | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/Marlin/src/lcd/ultralcd.cpp b/Marlin/src/lcd/ultralcd.cpp
index 5b01604d9..0517f5b80 100644
--- a/Marlin/src/lcd/ultralcd.cpp
+++ b/Marlin/src/lcd/ultralcd.cpp
@@ -4931,7 +4931,7 @@ void lcd_reset_alert_level() { lcd_status_message_level = 0; }
     #define encrot3 1
   #endif
 
-  #define GET_BUTTON_STATES(DST) \
+  #define GET_SHIFT_BUTTON_STATES(DST) \
     uint8_t new_##DST = 0; \
     WRITE(SHIFT_LD, LOW); \
     WRITE(SHIFT_LD, HIGH); \
@@ -5033,13 +5033,15 @@ void lcd_reset_alert_level() { lcd_status_message_level = 0; }
 
         #elif ENABLED(REPRAPWORLD_KEYPAD)
 
-          GET_BUTTON_STATES(buttons_reprapworld_keypad);
+          GET_SHIFT_BUTTON_STATES(buttons_reprapworld_keypad);
 
         #endif
 
-      #else
-        GET_BUTTON_STATES(buttons);
-      #endif // !NEWPANEL
+      #else // !NEWPANEL
+
+        GET_SHIFT_BUTTON_STATES(buttons);
+
+      #endif
 
     } // next_button_update_ms