Add support for Triple-Z steppers/endstops

Marlin/src/config/default/Configuration.h

@@ -587,6 +587,7 @@
 //#define X2_DRIVER_TYPE A4988
 //#define Y2_DRIVER_TYPE A4988
 //#define Z2_DRIVER_TYPE A4988
+//#define Z3_DRIVER_TYPE A4988
 //#define E0_DRIVER_TYPE A4988
 //#define E1_DRIVER_TYPE A4988
 //#define E2_DRIVER_TYPE A4988

Marlin/src/config/default/Configuration_adv.h

@@ -338,6 +338,17 @@
   #endif
 #endif
 
+//#define Z_TRIPLE_STEPPER_DRIVERS
+#if ENABLED(Z_TRIPLE_STEPPER_DRIVERS)
+  //#define Z_TRIPLE_ENDSTOPS
+  #if ENABLED(Z_TRIPLE_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z3_USE_ENDSTOP _YMAX_
+    #define Z_TRIPLE_ENDSTOPS_ADJUSTMENT2  0
+    #define Z_TRIPLE_ENDSTOPS_ADJUSTMENT3  0
+  #endif
+#endif
+
 /**
  * Dual X Carriage
  *
@@ -1087,6 +1098,10 @@
   #define Z2_SENSE_RESISTOR   91
   #define Z2_MICROSTEPS       16
 
+  #define Z3_MAX_CURRENT    1000
+  #define Z3_SENSE_RESISTOR   91
+  #define Z3_MICROSTEPS       16
+
   #define E0_MAX_CURRENT    1000
   #define E0_SENSE_RESISTOR   91
   #define E0_MICROSTEPS       16
@@ -1153,6 +1168,9 @@
   #define Z2_CURRENT         800
   #define Z2_MICROSTEPS       16
 
+  #define Z3_CURRENT         800
+  #define Z3_MICROSTEPS       16
+
   #define E0_CURRENT         800
   #define E0_MICROSTEPS       16
 
@@ -1217,6 +1235,7 @@
   #define Y2_HYBRID_THRESHOLD    100
   #define Z_HYBRID_THRESHOLD       3
   #define Z2_HYBRID_THRESHOLD      3
+  #define Z3_HYBRID_THRESHOLD      3
   #define E0_HYBRID_THRESHOLD     30
   #define E1_HYBRID_THRESHOLD     30
   #define E2_HYBRID_THRESHOLD     30
@@ -1315,6 +1334,10 @@
   #define Z2_OVERCURRENT    2000
   #define Z2_STALLCURRENT   1500
 
+  #define Z3_MICROSTEPS       16
+  #define Z3_OVERCURRENT    2000
+  #define Z3_STALLCURRENT   1500
+
   #define E0_MICROSTEPS       16
   #define E0_OVERCURRENT    2000
   #define E0_STALLCURRENT   1500