Allow G34 on Raptor with Trex board

Marlin/Configuration.h

@@ -35,11 +35,13 @@
 //#define SKR14
 //#define SKR14Turbo
 //#define SKRPRO11
+//#define Trex3Board
+//#define RaptorFanPins // When using the trex board, invert fan pins to match raptor extruder PCB
 
 //#define I2C_EEPROM  // use I2C EEPROM on SRK PRO v1.1 e.g AT24C256
 //#define SKR14_PowerLossKit // Bigtreetech power loss kit for SKR14
 
-//#define DualZ // Uses 5th driver on SKR boards as Z2
+//#define DualZ // Uses 5th driver on SKR Or Trex 3 (Use X2 plug) boards as Z2
 
 /**
  * Enable if you install a KEENOVO AC BED with Solid State Relay
@@ -102,6 +104,17 @@
 #if ANY(SKR13, SKR14, SKR14Turbo, SKRPRO11)
   #define SKRBoard
 #endif
+
+#if ENABLED(Trex3Board)
+  #define Z2_STEP_PIN                           42
+  #define Z2_DIR_PIN                            43
+  #define Z2_ENABLE_PIN                         44
+
+  #if ENABLED(RaptorFanPins)
+    #define FAN_PIN 6
+  #endif
+#endif
+
 /**
  * Marlin 3D Printer Firmware
  * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
@@ -250,6 +263,8 @@
     #define MOTHERBOARD BOARD_BTT_SKR_V1_3
   #elif ENABLED(SKRPRO11)
     #define MOTHERBOARD BOARD_BTT_SKR_PRO_V1_1
+  #elif ENABLED(Trex3Board)
+    #define MOTHERBOARD BOARD_FORMBOT_TREX3
   #elif ENABLED(RAPTOR2)
     #define MOTHERBOARD BOARD_FORMBOT_RAPTOR2
   #else

Marlin/Configuration_adv.h

@@ -480,7 +480,9 @@
  * Multiple extruders can be assigned to the same pin in which case
  * the fan will turn on when any selected extruder is above the threshold.
  */
-#if ENABLED(RAPTOR2) && DISABLED(SKRBoard)
+#if ENABLED(Trex3Board) && DISABLED(RaptorFanPins)
+  #define E0_AUTO_FAN_PIN 6
+#elif ENABLED(RAPTOR2) && DISABLED(SKRBoard)
   #define E0_AUTO_FAN_PIN 9
 #else
   #define E0_AUTO_FAN_PIN -1
@@ -585,7 +587,7 @@
 //
 // For Z set the number of stepper drivers
 //
-#if ENABLED(SKRBoard) && ENABLED(DualZ)
+#if ANY(SKRBoard, Trex3Board) && ENABLED(DualZ)
   #define NUM_Z_STEPPER_DRIVERS 2   // (1-4) Z options change based on how many
 #else
   #define NUM_Z_STEPPER_DRIVERS 1   // (1-4) Z options change based on how many
@@ -762,7 +764,7 @@
  * Z Steppers Auto-Alignment
  * Add the G34 command to align multiple Z steppers using a bed probe.
  */
-#if ENABLED(SKRBoard) && ENABLED(DualZ)
+#if ANY(SKRBoard, Trex3Board) && ENABLED(DualZ)
   #define Z_STEPPER_AUTO_ALIGN
 #endif
 #if ENABLED(Z_STEPPER_AUTO_ALIGN)

Marlin/src/pins/ramps/pins_FORMBOT_TREX3.h

@@ -124,10 +124,15 @@
 #define HEATER_1_PIN                           7
 #define HEATER_BED_PIN                         8
 
-#define FAN_PIN                                9
+#ifndef FAN_PIN
+  #define FAN_PIN                                9
+#endif
 #define FAN1_PIN                              12
 
-#define NUM_RUNOUT_SENSORS                     2
+#ifndef NUM_RUNOUT_SENSORS
+  #define NUM_RUNOUT_SENSORS                     2
+#endif
+
 #define FIL_RUNOUT_PIN                        22
 #define FIL_RUNOUT2_PIN                       21