From 5ccb1c9e7d49dc2496574b925d74f78393606028 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <sourcetree@thinkyhead.com>
Date: Mon, 15 Jun 2015 17:55:39 -0700
Subject: [PATCH] Use millis for M600 audio feedback interval

---
 Marlin/Marlin_main.cpp | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/Marlin/Marlin_main.cpp b/Marlin/Marlin_main.cpp
index 4b77c64bae..9a7c290942 100644
--- a/Marlin/Marlin_main.cpp
+++ b/Marlin/Marlin_main.cpp
@@ -4963,10 +4963,14 @@ inline void gcode_M503() {
     disable_e3();
     delay(100);
     LCD_ALERTMESSAGEPGM(MSG_FILAMENTCHANGE);
-    uint8_t cnt = 0;
+    millis_t next_tick = 0;
     while (!lcd_clicked()) {
       #ifndef AUTO_FILAMENT_CHANGE
-        if (++cnt == 0) lcd_quick_feedback(); // every 256th frame till the lcd is clicked
+        millis_t ms = millis();
+        if (ms >= next_tick) {
+          lcd_quick_feedback();
+          next_tick = ms + 2500; // feedback every 2.5s while waiting
+        }
         manage_heater();
         manage_inactivity(true);
         lcd_update();
@@ -4976,6 +4980,7 @@ inline void gcode_M503() {
         st_synchronize();
       #endif
     } // while(!lcd_clicked)
+    lcd_quick_feedback(); // click sound feedback
 
     #ifdef AUTO_FILAMENT_CHANGE
       current_position[E_AXIS]= 0;