From 8600cbb01b7fb37cec5944db27f5aae412b32dd2 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <github@thinkyhead.com>
Date: Mon, 25 Jun 2018 11:49:36 -0400
Subject: [PATCH] Clear Max7219 without test pattern

---
 Marlin/Marlin_main.cpp        | 2 +-
 Marlin/Max7219_Debug_LEDs.cpp | 4 ++++
 Marlin/Max7219_Debug_LEDs.h   | 3 +++
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/Marlin/Marlin_main.cpp b/Marlin/Marlin_main.cpp
index fa9d1742a..7bd45c57a 100644
--- a/Marlin/Marlin_main.cpp
+++ b/Marlin/Marlin_main.cpp
@@ -10882,7 +10882,7 @@ inline void gcode_M502() {
    */
   inline void gcode_M7219() {
     if (parser.seen('I'))
-      Max7219_init();
+      Max7219_Clear();
     else if (parser.seenval('R')) {
       const uint8_t r = parser.value_int();
       Max7219_Set_Row(r, parser.byteval('V'));
diff --git a/Marlin/Max7219_Debug_LEDs.cpp b/Marlin/Max7219_Debug_LEDs.cpp
index 2defab26c..eba1ffcd2 100644
--- a/Marlin/Max7219_Debug_LEDs.cpp
+++ b/Marlin/Max7219_Debug_LEDs.cpp
@@ -242,6 +242,10 @@ void Max7219_Clear_Column(const uint8_t _COL_) {
   #endif
 }
 
+void Max7219_Clear() {
+  for (uint8_t r = 0; r < 8; r++) _Max7219_Set_Reg(r, 0);
+}
+
 void Max7219_Set_2_Rows(const uint8_t y, uint16_t val) {
   if (y > 6) return Max7219_Error(PSTR("Max7219_Set_2_Rows"), y, val);
   Max7219_Set_Row(y + 0, val & 0xFF); val >>= 8;
diff --git a/Marlin/Max7219_Debug_LEDs.h b/Marlin/Max7219_Debug_LEDs.h
index dec159cee..f00f23174 100644
--- a/Marlin/Max7219_Debug_LEDs.h
+++ b/Marlin/Max7219_Debug_LEDs.h
@@ -77,6 +77,9 @@ void Max7219_Clear_Column(const uint8_t col);
 void Max7219_Set_Row(const uint8_t row, const uint8_t val);
 void Max7219_Clear_Row(const uint8_t row);
 
+// Quickly clear the whole matrix
+void Max7219_Clear();
+
 // Apply custom code to update the matrix
 void Max7219_idle_tasks();