Add Copymaster3D board (#17188)

Marlin/src/pins/pins.h

@@ -188,6 +188,8 @@
   #include "ramps/pins_TANGO.h"                 // ATmega2560                             env:mega2560
 #elif MB(MKS_GEN_L_V2)
   #include "ramps/pins_MKS_GEN_L_V2.h"          // ATmega2560                             env:mega2560
+#elif MB(COPYMASTER_3D)
+  #include "ramps/pins_COPYMASTER_3D.h"         // ATmega2560                             env:mega2560
 
 //
 // RAMBo and derivatives

Marlin/src/pins/ramps/pins_COPYMASTER_3D.h

@@ -0,0 +1,33 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+#pragma once
+
+#define BOARD_INFO_NAME "Copymaster 3D RAMPS"
+
+#define Z_STEP_PIN        47
+#define FIL_RUNOUT_PIN    15
+#define SD_DETECT_PIN     66
+
+//
+// Import RAMPS 1.4 pins
+//
+#include "pins_RAMPS.h"

Marlin/src/pins/ramps/pins_RAMPS.h

@@ -133,7 +133,9 @@
   #define Y_CS_PIN         49
 #endif
 
-#define Z_STEP_PIN         46
+#ifndef Z_STEP_PIN
+  #define Z_STEP_PIN       46
+#endif
 #define Z_DIR_PIN          48
 #define Z_ENABLE_PIN       62
 #ifndef Z_CS_PIN