Merge pull request #8123 from thinkyhead/bf1_dual_xyz_endstops

[1.1.x] Dual endstops XYZ

.travis.yml

@@ -199,12 +199,11 @@ script:
   #
   - restore_configs
   - opt_enable ULTIMAKERCONTROLLER FILAMENT_LCD_DISPLAY FILAMENT_WIDTH_SENSOR SDSUPPORT
-  - opt_enable PRINTCOUNTER NOZZLE_PARK_FEATURE NOZZLE_CLEAN_FEATURE PCA9632
+  - opt_enable PRINTCOUNTER NOZZLE_PARK_FEATURE NOZZLE_CLEAN_FEATURE PCA9632 USE_XMAX_PLUG
   - opt_enable_adv Z_DUAL_STEPPER_DRIVERS Z_DUAL_ENDSTOPS BEZIER_CURVE_SUPPORT EXPERIMENTAL_I2CBUS
   - opt_set_adv I2C_SLAVE_ADDRESS 63
   - opt_enable_adv ADVANCED_PAUSE_FEATURE PARK_HEAD_ON_PAUSE LCD_INFO_MENU
-  - pins_set RAMPS X_MAX_PIN -1
-  - opt_set_adv Z2_MAX_PIN 2
+  - opt_add_adv Z2_MIN_PIN 2
   - build_marlin
   #
   # Enable COREXY

Marlin/Conditionals_post.h

@@ -379,28 +379,113 @@
   #define ARRAY_BY_HOTENDS1(v1) ARRAY_BY_HOTENDS(v1, v1, v1, v1, v1, v1)
 
   /**
+   * X_DUAL_ENDSTOPS endstop reassignment
+   */
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #if X_HOME_DIR > 0
+      #if X2_USE_ENDSTOP == _XMIN_
+        #define X2_MAX_ENDSTOP_INVERTING X_MIN_ENDSTOP_INVERTING
+        #define X2_MAX_PIN X_MIN_PIN
+      #elif X2_USE_ENDSTOP == _XMAX_
+        #define X2_MAX_ENDSTOP_INVERTING X_MAX_ENDSTOP_INVERTING
+        #define X2_MAX_PIN X_MAX_PIN
+      #elif X2_USE_ENDSTOP == _YMIN_
+        #define X2_MAX_ENDSTOP_INVERTING Y_MIN_ENDSTOP_INVERTING
+        #define X2_MAX_PIN Y_MIN_PIN
+      #elif X2_USE_ENDSTOP == _YMAX_
+        #define X2_MAX_ENDSTOP_INVERTING Y_MAX_ENDSTOP_INVERTING
+        #define X2_MAX_PIN Y_MAX_PIN
+      #elif X2_USE_ENDSTOP == _ZMIN_
+        #define X2_MAX_ENDSTOP_INVERTING Z_MIN_ENDSTOP_INVERTING
+        #define X2_MAX_PIN Z_MIN_PIN
+      #elif X2_USE_ENDSTOP == _ZMAX_
+        #define X2_MAX_ENDSTOP_INVERTING Z_MAX_ENDSTOP_INVERTING
+        #define X2_MAX_PIN Z_MAX_PIN
+      #else
+        #define X2_MAX_ENDSTOP_INVERTING false
+      #endif
+    #elif X2_USE_ENDSTOP == _XMIN_
+      #define X2_MIN_ENDSTOP_INVERTING X_MIN_ENDSTOP_INVERTING
+      #define X2_MIN_PIN X_MIN_PIN
+    #elif X2_USE_ENDSTOP == _XMAX_
+      #define X2_MIN_ENDSTOP_INVERTING X_MAX_ENDSTOP_INVERTING
+      #define X2_MIN_PIN X_MAX_PIN
+    #elif X2_USE_ENDSTOP == _YMIN_
+      #define X2_MIN_ENDSTOP_INVERTING Y_MIN_ENDSTOP_INVERTING
+      #define X2_MIN_PIN Y_MIN_PIN
+    #elif X2_USE_ENDSTOP == _YMAX_
+      #define X2_MIN_ENDSTOP_INVERTING Y_MAX_ENDSTOP_INVERTING
+      #define X2_MIN_PIN Y_MAX_PIN
+    #elif X2_USE_ENDSTOP == _ZMIN_
+      #define X2_MIN_ENDSTOP_INVERTING Z_MIN_ENDSTOP_INVERTING
+      #define X2_MIN_PIN Z_MIN_PIN
+    #elif X2_USE_ENDSTOP == _ZMAX_
+      #define X2_MIN_ENDSTOP_INVERTING Z_MAX_ENDSTOP_INVERTING
+      #define X2_MIN_PIN Z_MAX_PIN
+    #else
+      #define X2_MIN_ENDSTOP_INVERTING false
+    #endif
+  #endif
+
+  // Is an endstop plug used for the X2 endstop?
+  #define IS_X2_ENDSTOP(A,M) (ENABLED(X_DUAL_ENDSTOPS) && X2_USE_ENDSTOP == _##A##M##_)
+
+  /**
+   * Y_DUAL_ENDSTOPS endstop reassignment
+   */
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #if Y_HOME_DIR > 0
+      #if Y2_USE_ENDSTOP == _XMIN_
+        #define Y2_MAX_ENDSTOP_INVERTING X_MIN_ENDSTOP_INVERTING
+        #define Y2_MAX_PIN X_MIN_PIN
+      #elif Y2_USE_ENDSTOP == _XMAX_
+        #define Y2_MAX_ENDSTOP_INVERTING X_MAX_ENDSTOP_INVERTING
+        #define Y2_MAX_PIN X_MAX_PIN
+      #elif Y2_USE_ENDSTOP == _YMIN_
+        #define Y2_MAX_ENDSTOP_INVERTING Y_MIN_ENDSTOP_INVERTING
+        #define Y2_MAX_PIN Y_MIN_PIN
+      #elif Y2_USE_ENDSTOP == _YMAX_
+        #define Y2_MAX_ENDSTOP_INVERTING Y_MAX_ENDSTOP_INVERTING
+        #define Y2_MAX_PIN Y_MAX_PIN
+      #elif Y2_USE_ENDSTOP == _ZMIN_
+        #define Y2_MAX_ENDSTOP_INVERTING Z_MIN_ENDSTOP_INVERTING
+        #define Y2_MAX_PIN Z_MIN_PIN
+      #elif Y2_USE_ENDSTOP == _ZMAX_
+        #define Y2_MAX_ENDSTOP_INVERTING Z_MAX_ENDSTOP_INVERTING
+        #define Y2_MAX_PIN Z_MAX_PIN
+      #else
+        #define Y2_MAX_ENDSTOP_INVERTING false
+      #endif
+    #elif Y2_USE_ENDSTOP == _XMIN_
+      #define Y2_MIN_ENDSTOP_INVERTING X_MIN_ENDSTOP_INVERTING
+      #define Y2_MIN_PIN X_MIN_PIN
+    #elif Y2_USE_ENDSTOP == _XMAX_
+      #define Y2_MIN_ENDSTOP_INVERTING X_MAX_ENDSTOP_INVERTING
+      #define Y2_MIN_PIN X_MAX_PIN
+    #elif Y2_USE_ENDSTOP == _YMIN_
+      #define Y2_MIN_ENDSTOP_INVERTING Y_MIN_ENDSTOP_INVERTING
+      #define Y2_MIN_PIN Y_MIN_PIN
+    #elif Y2_USE_ENDSTOP == _YMAX_
+      #define Y2_MIN_ENDSTOP_INVERTING Y_MAX_ENDSTOP_INVERTING
+      #define Y2_MIN_PIN Y_MAX_PIN
+    #elif Y2_USE_ENDSTOP == _ZMIN_
+      #define Y2_MIN_ENDSTOP_INVERTING Z_MIN_ENDSTOP_INVERTING
+      #define Y2_MIN_PIN Z_MIN_PIN
+    #elif Y2_USE_ENDSTOP == _ZMAX_
+      #define Y2_MIN_ENDSTOP_INVERTING Z_MAX_ENDSTOP_INVERTING
+      #define Y2_MIN_PIN Z_MAX_PIN
+    #else
+      #define Y2_MIN_ENDSTOP_INVERTING false
+    #endif
+  #endif
+
+  // Is an endstop plug used for the Y2 endstop or the bed probe?
+  #define IS_Y2_ENDSTOP(A,M) (ENABLED(Y_DUAL_ENDSTOPS) && Y2_USE_ENDSTOP == _##A##M##_)
+
+  /**
    * Z_DUAL_ENDSTOPS endstop reassignment
    */
   #if ENABLED(Z_DUAL_ENDSTOPS)
-    #define _XMIN_ 100
-    #define _YMIN_ 200
-    #define _ZMIN_ 300
-    #define _XMAX_ 101
-    #define _YMAX_ 201
-    #define _ZMAX_ 301
-    #if Z2_USE_ENDSTOP == _XMIN_
-      #define USE_XMIN_PLUG
-    #elif Z2_USE_ENDSTOP == _XMAX_
-      #define USE_XMAX_PLUG
-    #elif Z2_USE_ENDSTOP == _YMIN_
-      #define USE_YMIN_PLUG
-    #elif Z2_USE_ENDSTOP == _YMAX_
-      #define USE_YMAX_PLUG
-    #elif Z2_USE_ENDSTOP == _ZMIN_
-      #define USE_ZMIN_PLUG
-    #elif Z2_USE_ENDSTOP == _ZMAX_
-      #define USE_ZMAX_PLUG
-    #endif
     #if Z_HOME_DIR > 0
       #if Z2_USE_ENDSTOP == _XMIN_
         #define Z2_MAX_ENDSTOP_INVERTING X_MIN_ENDSTOP_INVERTING
@@ -423,28 +508,26 @@
       #else
         #define Z2_MAX_ENDSTOP_INVERTING false
       #endif
+    #elif Z2_USE_ENDSTOP == _XMIN_
+      #define Z2_MIN_ENDSTOP_INVERTING X_MIN_ENDSTOP_INVERTING
+      #define Z2_MIN_PIN X_MIN_PIN
+    #elif Z2_USE_ENDSTOP == _XMAX_
+      #define Z2_MIN_ENDSTOP_INVERTING X_MAX_ENDSTOP_INVERTING
+      #define Z2_MIN_PIN X_MAX_PIN
+    #elif Z2_USE_ENDSTOP == _YMIN_
+      #define Z2_MIN_ENDSTOP_INVERTING Y_MIN_ENDSTOP_INVERTING
+      #define Z2_MIN_PIN Y_MIN_PIN
+    #elif Z2_USE_ENDSTOP == _YMAX_
+      #define Z2_MIN_ENDSTOP_INVERTING Y_MAX_ENDSTOP_INVERTING
+      #define Z2_MIN_PIN Y_MAX_PIN
+    #elif Z2_USE_ENDSTOP == _ZMIN_
+      #define Z2_MIN_ENDSTOP_INVERTING Z_MIN_ENDSTOP_INVERTING
+      #define Z2_MIN_PIN Z_MIN_PIN
+    #elif Z2_USE_ENDSTOP == _ZMAX_
+      #define Z2_MIN_ENDSTOP_INVERTING Z_MAX_ENDSTOP_INVERTING
+      #define Z2_MIN_PIN Z_MAX_PIN
     #else
-      #if Z2_USE_ENDSTOP == _XMIN_
-        #define Z2_MIN_ENDSTOP_INVERTING X_MIN_ENDSTOP_INVERTING
-        #define Z2_MIN_PIN X_MIN_PIN
-      #elif Z2_USE_ENDSTOP == _XMAX_
-        #define Z2_MIN_ENDSTOP_INVERTING X_MAX_ENDSTOP_INVERTING
-        #define Z2_MIN_PIN X_MAX_PIN
-      #elif Z2_USE_ENDSTOP == _YMIN_
-        #define Z2_MIN_ENDSTOP_INVERTING Y_MIN_ENDSTOP_INVERTING
-        #define Z2_MIN_PIN Y_MIN_PIN
-      #elif Z2_USE_ENDSTOP == _YMAX_
-        #define Z2_MIN_ENDSTOP_INVERTING Y_MAX_ENDSTOP_INVERTING
-        #define Z2_MIN_PIN Y_MAX_PIN
-      #elif Z2_USE_ENDSTOP == _ZMIN_
-        #define Z2_MIN_ENDSTOP_INVERTING Z_MIN_ENDSTOP_INVERTING
-        #define Z2_MIN_PIN Z_MIN_PIN
-      #elif Z2_USE_ENDSTOP == _ZMAX_
-        #define Z2_MIN_ENDSTOP_INVERTING Z_MAX_ENDSTOP_INVERTING
-        #define Z2_MIN_PIN Z_MAX_PIN
-      #else
-        #define Z2_MIN_ENDSTOP_INVERTING false
-      #endif
+      #define Z2_MIN_ENDSTOP_INVERTING false
     #endif
   #endif
 
@@ -541,12 +624,16 @@
   #define HAS_SOLENOID_4    (PIN_EXISTS(SOL4))
 
   // Endstops and bed probe
-  #define HAS_X_MIN (PIN_EXISTS(X_MIN) && !IS_Z2_OR_PROBE(X,MIN))
-  #define HAS_X_MAX (PIN_EXISTS(X_MAX) && !IS_Z2_OR_PROBE(X,MAX))
-  #define HAS_Y_MIN (PIN_EXISTS(Y_MIN) && !IS_Z2_OR_PROBE(Y,MIN))
-  #define HAS_Y_MAX (PIN_EXISTS(Y_MAX) && !IS_Z2_OR_PROBE(Y,MAX))
-  #define HAS_Z_MIN (PIN_EXISTS(Z_MIN) && !IS_Z2_OR_PROBE(Z,MIN))
-  #define HAS_Z_MAX (PIN_EXISTS(Z_MAX) && !IS_Z2_OR_PROBE(Z,MAX))
+  #define HAS_X_MIN (PIN_EXISTS(X_MIN) && !IS_X2_ENDSTOP(X,MIN) && !IS_Y2_ENDSTOP(X,MIN) && !IS_Z2_OR_PROBE(X,MIN))
+  #define HAS_X_MAX (PIN_EXISTS(X_MAX) && !IS_X2_ENDSTOP(X,MAX) && !IS_Y2_ENDSTOP(X,MAX) && !IS_Z2_OR_PROBE(X,MAX))
+  #define HAS_Y_MIN (PIN_EXISTS(Y_MIN) && !IS_X2_ENDSTOP(Y,MIN) && !IS_Y2_ENDSTOP(Y,MIN) && !IS_Z2_OR_PROBE(Y,MIN))
+  #define HAS_Y_MAX (PIN_EXISTS(Y_MAX) && !IS_X2_ENDSTOP(Y,MAX) && !IS_Y2_ENDSTOP(Y,MAX) && !IS_Z2_OR_PROBE(Y,MAX))
+  #define HAS_Z_MIN (PIN_EXISTS(Z_MIN) && !IS_X2_ENDSTOP(Z,MIN) && !IS_Y2_ENDSTOP(Z,MIN) && !IS_Z2_OR_PROBE(Z,MIN))
+  #define HAS_Z_MAX (PIN_EXISTS(Z_MAX) && !IS_X2_ENDSTOP(Z,MAX) && !IS_Y2_ENDSTOP(Z,MAX) && !IS_Z2_OR_PROBE(Z,MAX))
+  #define HAS_X2_MIN (PIN_EXISTS(X2_MIN))
+  #define HAS_X2_MAX (PIN_EXISTS(X2_MAX))
+  #define HAS_Y2_MIN (PIN_EXISTS(Y2_MIN))
+  #define HAS_Y2_MAX (PIN_EXISTS(Y2_MAX))
   #define HAS_Z2_MIN (PIN_EXISTS(Z2_MIN))
   #define HAS_Z2_MAX (PIN_EXISTS(Z2_MAX))
   #define HAS_Z_MIN_PROBE_PIN (PIN_EXISTS(Z_MIN_PROBE))

Marlin/Configuration_adv.h

@@ -257,48 +257,49 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
-// Dual X Steppers
-// Uncomment this option to drive two X axis motors.
-// The next unused E driver will be assigned to the second X stepper.
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
 //#define X_DUAL_STEPPER_DRIVERS
 #if ENABLED(X_DUAL_STEPPER_DRIVERS)
-  // Set true if the two X motors need to rotate in opposite directions
-  #define INVERT_X2_VS_X_DIR true
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
 #endif
 
-// Dual Y Steppers
-// Uncomment this option to drive two Y axis motors.
-// The next unused E driver will be assigned to the second Y stepper.
 //#define Y_DUAL_STEPPER_DRIVERS
 #if ENABLED(Y_DUAL_STEPPER_DRIVERS)
-  // Set true if the two Y motors need to rotate in opposite directions
-  #define INVERT_Y2_VS_Y_DIR true
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
 #endif
 
-// A single Z stepper driver is usually used to drive 2 stepper motors.
-// Uncomment this option to use a separate stepper driver for each Z axis motor.
-// The next unused E driver will be assigned to the second Z stepper.
 //#define Z_DUAL_STEPPER_DRIVERS
-
 #if ENABLED(Z_DUAL_STEPPER_DRIVERS)
-
-  // Z_DUAL_ENDSTOPS is a feature to enable the use of 2 endstops for both Z steppers - Let's call them Z stepper and Z2 stepper.
-  // That way the machine is capable to align the bed during home, since both Z steppers are homed.
-  // There is also an implementation of M666 (software endstops adjustment) to this feature.
-  // After Z homing, this adjustment is applied to just one of the steppers in order to align the bed.
-  // One just need to home the Z axis and measure the distance difference between both Z axis and apply the math: Z adjust = Z - Z2.
-  // If the Z stepper axis is closer to the bed, the measure Z > Z2 (yes, it is.. think about it) and the Z adjust would be positive.
-  // Play a little bit with small adjustments (0.5mm) and check the behaviour.
-  // The M119 (endstops report) will start reporting the Z2 Endstop as well.
-
   //#define Z_DUAL_ENDSTOPS
-
   #if ENABLED(Z_DUAL_ENDSTOPS)
     #define Z2_USE_ENDSTOP _XMAX_
-    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0  // Use M666 to determine/test this value
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
   #endif
-
-#endif // Z_DUAL_STEPPER_DRIVERS
+#endif
 
 // Enable this for dual x-carriage printers.
 // A dual x-carriage design has the advantage that the inactive extruder can be parked which
@@ -434,8 +435,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/Marlin.h

@@ -331,6 +331,12 @@ extern float soft_endstop_min[XYZ], soft_endstop_max[XYZ];
   void set_z_fade_height(const float zfh);
 #endif
 
+#if ENABLED(X_DUAL_ENDSTOPS)
+  extern float x_endstop_adj;
+#endif
+#if ENABLED(Y_DUAL_ENDSTOPS)
+  extern float y_endstop_adj;
+#endif
 #if ENABLED(Z_DUAL_ENDSTOPS)
   extern float z_endstop_adj;
 #endif

Marlin/Marlin_main.cpp

@@ -562,13 +562,19 @@ static uint8_t target_extruder;
   #define ADJUST_DELTA(V) NOOP
 #endif
 
+#if ENABLED(X_DUAL_ENDSTOPS)
+  float x_endstop_adj;                // Initialized by settings.load()
+#endif
+#if ENABLED(Y_DUAL_ENDSTOPS)
+  float y_endstop_adj;                // Initialized by settings.load()
+#endif
 #if ENABLED(Z_DUAL_ENDSTOPS)
-  float z_endstop_adj;
+  float z_endstop_adj;                // Initialized by settings.load()
 #endif
 
 // Extruder offsets
 #if HOTENDS > 1
-  float hotend_offset[XYZ][HOTENDS]; // Initialized by settings.load()
+  float hotend_offset[XYZ][HOTENDS];  // Initialized by settings.load()
 #endif
 
 #if HAS_Z_SERVO_ENDSTOP
@@ -3017,9 +3023,15 @@ static void homeaxis(const AxisEnum axis) {
     if (axis == Z_AXIS && DEPLOY_PROBE()) return;
   #endif
 
-  // Set a flag for Z motor locking
+  // Set flags for X, Y, Z motor locking
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    if (axis == X_AXIS) stepper.set_homing_flag_x(true);
+  #endif
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    if (axis == Y_AXIS) stepper.set_homing_flag_y(true);
+  #endif
   #if ENABLED(Z_DUAL_ENDSTOPS)
-    if (axis == Z_AXIS) stepper.set_homing_flag(true);
+    if (axis == Z_AXIS) stepper.set_homing_flag_z(true);
   #endif
 
   // Disable stealthChop if used. Enable diag1 pin on driver.
@@ -3061,25 +3073,41 @@ static void homeaxis(const AxisEnum axis) {
     do_homing_move(axis, 2 * bump, get_homing_bump_feedrate(axis));
   }
 
-  #if ENABLED(Z_DUAL_ENDSTOPS)
-    if (axis == Z_AXIS) {
-      float adj = FABS(z_endstop_adj);
-      bool lockZ1;
-      if (axis_home_dir > 0) {
-        adj = -adj;
-        lockZ1 = (z_endstop_adj > 0);
+  /**
+   * Home axes that have dual endstops... differently
+   */
+  #if ENABLED(X_DUAL_ENDSTOPS) || ENABLED(Y_DUAL_ENDSTOPS) || ENABLED(Z_DUAL_ENDSTOPS)
+    const bool pos_dir = axis_home_dir > 0;
+    #if ENABLED(X_DUAL_ENDSTOPS)
+      if (axis == X_AXIS) {
+        const bool lock_x1 = pos_dir ? (x_endstop_adj > 0) : (x_endstop_adj < 0);
+        const float adj = FABS(x_endstop_adj);
+        if (lock_x1) stepper.set_x_lock(true); else stepper.set_x2_lock(true);
+        do_homing_move(axis, pos_dir ? -adj : adj);
+        if (lock_x1) stepper.set_x_lock(false); else stepper.set_x2_lock(false);
+        stepper.set_homing_flag_x(false);
       }
-      else
-        lockZ1 = (z_endstop_adj < 0);
-
-      if (lockZ1) stepper.set_z_lock(true); else stepper.set_z2_lock(true);
-
-      // Move to the adjusted endstop height
-      do_homing_move(axis, adj);
-
-      if (lockZ1) stepper.set_z_lock(false); else stepper.set_z2_lock(false);
-      stepper.set_homing_flag(false);
-    } // Z_AXIS
+    #endif
+    #if ENABLED(Y_DUAL_ENDSTOPS)
+      if (axis == Y_AXIS) {
+        const bool lock_y1 = pos_dir ? (y_endstop_adj > 0) : (y_endstop_adj < 0);
+        const float adj = FABS(y_endstop_adj);
+        if (lock_y1) stepper.set_y_lock(true); else stepper.set_y2_lock(true);
+        do_homing_move(axis, pos_dir ? -adj : adj);
+        if (lock_y1) stepper.set_y_lock(false); else stepper.set_y2_lock(false);
+        stepper.set_homing_flag_y(false);
+      }
+    #endif
+    #if ENABLED(Z_DUAL_ENDSTOPS)
+      if (axis == Z_AXIS) {
+        const bool lock_z1 = pos_dir ? (z_endstop_adj > 0) : (z_endstop_adj < 0);
+        const float adj = FABS(z_endstop_adj);
+        if (lock_z1) stepper.set_z_lock(true); else stepper.set_z2_lock(true);
+        do_homing_move(axis, pos_dir ? -adj : adj);
+        if (lock_z1) stepper.set_z_lock(false); else stepper.set_z2_lock(false);
+        stepper.set_homing_flag_z(false);
+      }
+    #endif
   #endif
 
   #if IS_SCARA
@@ -8894,14 +8922,28 @@ inline void gcode_M205() {
     }
   }
 
-#elif ENABLED(Z_DUAL_ENDSTOPS) // !DELTA && ENABLED(Z_DUAL_ENDSTOPS)
+
+
+#elif ENABLED(X_DUAL_ENDSTOPS) || ENABLED(Y_DUAL_ENDSTOPS) || ENABLED(Z_DUAL_ENDSTOPS)
 
   /**
    * M666: For Z Dual Endstop setup, set z axis offset to the z2 axis.
    */
   inline void gcode_M666() {
-    if (parser.seen('Z')) z_endstop_adj = parser.value_linear_units();
-    SERIAL_ECHOLNPAIR("Z Endstop Adjustment set to (mm):", z_endstop_adj);
+    SERIAL_ECHOPGM("Dual Endstop Adjustment (mm): ");
+    #if ENABLED(X_DUAL_ENDSTOPS)
+      if (parser.seen('X')) x_endstop_adj = parser.value_linear_units();
+      SERIAL_ECHOPAIR(" X", x_endstop_adj);
+    #endif
+    #if ENABLED(Y_DUAL_ENDSTOPS)
+      if (parser.seen('Y')) y_endstop_adj = parser.value_linear_units();
+      SERIAL_ECHOPAIR(" Y", y_endstop_adj);
+    #endif
+    #if ENABLED(Z_DUAL_ENDSTOPS)
+      if (parser.seen('Z')) z_endstop_adj = parser.value_linear_units();
+      SERIAL_ECHOPAIR(" Z", z_endstop_adj);
+    #endif
+    SERIAL_EOL();
   }
 
 #endif // !DELTA && Z_DUAL_ENDSTOPS
@@ -11606,7 +11648,7 @@ void process_next_command() {
           break;
       #endif
 
-      #if ENABLED(DELTA) || ENABLED(Z_DUAL_ENDSTOPS)
+      #if ENABLED(DELTA) || ENABLED(X_DUAL_ENDSTOPS) || ENABLED(Y_DUAL_ENDSTOPS) || ENABLED(Z_DUAL_ENDSTOPS)
         case 666: // M666: Set delta or dual endstop adjustment
           gcode_M666();
           break;
@@ -13949,4 +13991,3 @@ void loop() {
   endstops.report_state();
   idle();
 }
-

Marlin/SanityCheck.h

@@ -78,8 +78,6 @@
   #error "FILAMENT_SENSOR is deprecated. Use FILAMENT_WIDTH_SENSOR instead."
 #elif defined(DISABLE_MAX_ENDSTOPS) || defined(DISABLE_MIN_ENDSTOPS)
   #error "DISABLE_MAX_ENDSTOPS and DISABLE_MIN_ENDSTOPS deprecated. Use individual USE_*_PLUG options instead."
-#elif ENABLED(Z_DUAL_ENDSTOPS) && !defined(Z2_USE_ENDSTOP)
-  #error "Z_DUAL_ENDSTOPS settings are simplified. Just set Z2_USE_ENDSTOP to the endstop you want to repurpose for Z2."
 #elif defined(LANGUAGE_INCLUDE)
   #error "LANGUAGE_INCLUDE has been replaced by LCD_LANGUAGE. Please update your configuration."
 #elif defined(EXTRUDER_OFFSET_X) || defined(EXTRUDER_OFFSET_Y)
@@ -1059,23 +1057,25 @@ static_assert(1 >= 0
 #endif
 
 /**
- * Endstops
+ * Endstop Tests
  */
-#if DISABLED(USE_XMIN_PLUG) && DISABLED(USE_XMAX_PLUG) && !(ENABLED(Z_DUAL_ENDSTOPS) && WITHIN(Z2_USE_ENDSTOP, _XMAX_, _XMIN_))
- #error "You must enable USE_XMIN_PLUG or USE_XMAX_PLUG."
-#elif DISABLED(USE_YMIN_PLUG) && DISABLED(USE_YMAX_PLUG) && !(ENABLED(Z_DUAL_ENDSTOPS) && WITHIN(Z2_USE_ENDSTOP, _YMAX_, _YMIN_))
- #error "You must enable USE_YMIN_PLUG or USE_YMAX_PLUG."
-#elif DISABLED(USE_ZMIN_PLUG) && DISABLED(USE_ZMAX_PLUG) && !(ENABLED(Z_DUAL_ENDSTOPS) && WITHIN(Z2_USE_ENDSTOP, _ZMAX_, _ZMIN_))
- #error "You must enable USE_ZMIN_PLUG or USE_ZMAX_PLUG."
-#elif ENABLED(Z_DUAL_ENDSTOPS)
-  #if !Z2_USE_ENDSTOP
-    #error "You must set Z2_USE_ENDSTOP with Z_DUAL_ENDSTOPS."
-  #elif Z2_MAX_PIN == 0 && Z2_MIN_PIN == 0
-    #error "Z2_USE_ENDSTOP has been assigned to a nonexistent endstop!"
-  #elif ENABLED(DELTA)
-    #error "Z_DUAL_ENDSTOPS is not compatible with DELTA."
-  #endif
-#elif !IS_SCARA
+
+#define _PLUG_UNUSED_TEST(AXIS,PLUG) (DISABLED(USE_##PLUG##MIN_PLUG) && DISABLED(USE_##PLUG##MAX_PLUG) && !(ENABLED(AXIS##_DUAL_ENDSTOPS) && WITHIN(AXIS##2_USE_ENDSTOP, _##PLUG##MAX_, _##PLUG##MIN_)))
+#define _AXIS_PLUG_UNUSED_TEST(AXIS) (_PLUG_UNUSED_TEST(AXIS,X) && _PLUG_UNUSED_TEST(AXIS,Y) && _PLUG_UNUSED_TEST(AXIS,Z))
+
+// At least 3 endstop plugs must be used
+#if _AXIS_PLUG_UNUSED_TEST(X)
+  #error "You must enable USE_XMIN_PLUG or USE_XMAX_PLUG."
+#endif
+#if _AXIS_PLUG_UNUSED_TEST(Y)
+  #error "You must enable USE_YMIN_PLUG or USE_YMAX_PLUG."
+#endif
+#if _AXIS_PLUG_UNUSED_TEST(Z)
+  #error "You must enable USE_ZMIN_PLUG or USE_ZMAX_PLUG."
+#endif
+
+// Delta and Cartesian use 3 homing endstops
+#if !IS_SCARA
   #if X_HOME_DIR < 0 && DISABLED(USE_XMIN_PLUG)
     #error "Enable USE_XMIN_PLUG when homing X to MIN."
   #elif X_HOME_DIR > 0 && DISABLED(USE_XMAX_PLUG)
@@ -1084,10 +1084,76 @@ static_assert(1 >= 0
     #error "Enable USE_YMIN_PLUG when homing Y to MIN."
   #elif Y_HOME_DIR > 0 && DISABLED(USE_YMAX_PLUG)
     #error "Enable USE_YMAX_PLUG when homing Y to MAX."
-  #elif Z_HOME_DIR < 0 && DISABLED(USE_ZMIN_PLUG)
-    #error "Enable USE_ZMIN_PLUG when homing Z to MIN."
-  #elif Z_HOME_DIR > 0 && DISABLED(USE_ZMAX_PLUG)
-    #error "Enable USE_ZMAX_PLUG when homing Z to MAX."
+  #endif
+#endif
+#if Z_HOME_DIR < 0 && DISABLED(USE_ZMIN_PLUG)
+  #error "Enable USE_ZMIN_PLUG when homing Z to MIN."
+#elif Z_HOME_DIR > 0 && DISABLED(USE_ZMAX_PLUG)
+  #error "Enable USE_ZMAX_PLUG when homing Z to MAX."
+#endif
+
+// Dual endstops requirements
+#if ENABLED(X_DUAL_ENDSTOPS)
+  #if !X2_USE_ENDSTOP
+    #error "You must set X2_USE_ENDSTOP with X_DUAL_ENDSTOPS."
+  #elif X2_USE_ENDSTOP == _X_MIN_ && DISABLED(USE_XMIN_PLUG)
+    #error "USE_XMIN_PLUG is required when X2_USE_ENDSTOP is _X_MIN_."
+  #elif X2_USE_ENDSTOP == _X_MAX_ && DISABLED(USE_XMAX_PLUG)
+    #error "USE_XMAX_PLUG is required when X2_USE_ENDSTOP is _X_MAX_."
+  #elif X2_USE_ENDSTOP == _Y_MIN_ && DISABLED(USE_YMIN_PLUG)
+    #error "USE_YMIN_PLUG is required when X2_USE_ENDSTOP is _Y_MIN_."
+  #elif X2_USE_ENDSTOP == _Y_MAX_ && DISABLED(USE_YMAX_PLUG)
+    #error "USE_YMAX_PLUG is required when X2_USE_ENDSTOP is _Y_MAX_."
+  #elif X2_USE_ENDSTOP == _Z_MIN_ && DISABLED(USE_ZMIN_PLUG)
+    #error "USE_ZMIN_PLUG is required when X2_USE_ENDSTOP is _Z_MIN_."
+  #elif X2_USE_ENDSTOP == _Z_MAX_ && DISABLED(USE_ZMAX_PLUG)
+    #error "USE_ZMAX_PLUG is required when X2_USE_ENDSTOP is _Z_MAX_."
+  #elif !HAS_X2_MIN && !HAS_X2_MAX
+    #error "X2_USE_ENDSTOP has been assigned to a nonexistent endstop!"
+  #elif ENABLED(DELTA)
+    #error "X_DUAL_ENDSTOPS is not compatible with DELTA."
+  #endif
+#endif
+#if ENABLED(Y_DUAL_ENDSTOPS)
+  #if !Y2_USE_ENDSTOP
+    #error "You must set Y2_USE_ENDSTOP with Y_DUAL_ENDSTOPS."
+  #elif Y2_USE_ENDSTOP == _X_MIN_ && DISABLED(USE_XMIN_PLUG)
+    #error "USE_XMIN_PLUG is required when Y2_USE_ENDSTOP is _X_MIN_."
+  #elif Y2_USE_ENDSTOP == _X_MAX_ && DISABLED(USE_XMAX_PLUG)
+    #error "USE_XMAX_PLUG is required when Y2_USE_ENDSTOP is _X_MAX_."
+  #elif Y2_USE_ENDSTOP == _Y_MIN_ && DISABLED(USE_YMIN_PLUG)
+    #error "USE_YMIN_PLUG is required when Y2_USE_ENDSTOP is _Y_MIN_."
+  #elif Y2_USE_ENDSTOP == _Y_MAX_ && DISABLED(USE_YMAX_PLUG)
+    #error "USE_YMAX_PLUG is required when Y2_USE_ENDSTOP is _Y_MAX_."
+  #elif Y2_USE_ENDSTOP == _Z_MIN_ && DISABLED(USE_ZMIN_PLUG)
+    #error "USE_ZMIN_PLUG is required when Y2_USE_ENDSTOP is _Z_MIN_."
+  #elif Y2_USE_ENDSTOP == _Z_MAX_ && DISABLED(USE_ZMAX_PLUG)
+    #error "USE_ZMAX_PLUG is required when Y2_USE_ENDSTOP is _Z_MAX_."
+  #elif !HAS_Y2_MIN && !HAS_Y2_MAX
+    #error "Y2_USE_ENDSTOP has been assigned to a nonexistent endstop!"
+  #elif ENABLED(DELTA)
+    #error "Y_DUAL_ENDSTOPS is not compatible with DELTA."
+  #endif
+#endif
+#if ENABLED(Z_DUAL_ENDSTOPS)
+  #if !Z2_USE_ENDSTOP
+    #error "You must set Z2_USE_ENDSTOP with Z_DUAL_ENDSTOPS."
+  #elif Z2_USE_ENDSTOP == _X_MIN_ && DISABLED(USE_XMIN_PLUG)
+    #error "USE_XMIN_PLUG is required when Z2_USE_ENDSTOP is _X_MIN_."
+  #elif Z2_USE_ENDSTOP == _X_MAX_ && DISABLED(USE_XMAX_PLUG)
+    #error "USE_XMAX_PLUG is required when Z2_USE_ENDSTOP is _X_MAX_."
+  #elif Z2_USE_ENDSTOP == _Y_MIN_ && DISABLED(USE_YMIN_PLUG)
+    #error "USE_YMIN_PLUG is required when Z2_USE_ENDSTOP is _Y_MIN_."
+  #elif Z2_USE_ENDSTOP == _Y_MAX_ && DISABLED(USE_YMAX_PLUG)
+    #error "USE_YMAX_PLUG is required when Z2_USE_ENDSTOP is _Y_MAX_."
+  #elif Z2_USE_ENDSTOP == _Z_MIN_ && DISABLED(USE_ZMIN_PLUG)
+    #error "USE_ZMIN_PLUG is required when Z2_USE_ENDSTOP is _Z_MIN_."
+  #elif Z2_USE_ENDSTOP == _Z_MAX_ && DISABLED(USE_ZMAX_PLUG)
+    #error "USE_ZMAX_PLUG is required when Z2_USE_ENDSTOP is _Z_MAX_."
+  #elif !HAS_Z2_MIN && !HAS_Z2_MAX
+    #error "Z2_USE_ENDSTOP has been assigned to a nonexistent endstop!"
+  #elif ENABLED(DELTA)
+    #error "Z_DUAL_ENDSTOPS is not compatible with DELTA."
   #endif
 #endif
 

Marlin/configuration_store.cpp

@@ -36,13 +36,13 @@
  *
  */
 
-#define EEPROM_VERSION "V42"
+#define EEPROM_VERSION "V43"
 
 // Change EEPROM version if these are changed:
 #define EEPROM_OFFSET 100
 
 /**
- * V42 EEPROM Layout:
+ * V43 EEPROM Layout:
  *
  *  100  Version                                    (char x4)
  *  104  EEPROM CRC16                               (uint16_t)
@@ -87,82 +87,83 @@
  *  312  G29 L F   bilinear_start                   (int x2)
  *  316            z_values[][]                     (float x9, up to float x256) +988
  *
- * AUTO_BED_LEVELING_UBL:                           6 bytes
+ * AUTO_BED_LEVELING_UBL:                           2 bytes
  *  324  G29 A     planner.leveling_active          (bool)
  *  325  G29 S     ubl.storage_slot                 (int8_t)
  *
- * DELTA:                                           48 bytes
- *  348  M666 XYZ  delta_endstop_adj                (float x3)
- *  360  M665 R    delta_radius                     (float)
- *  364  M665 L    delta_diagonal_rod               (float)
- *  368  M665 S    delta_segments_per_second        (float)
- *  372  M665 B    delta_calibration_radius         (float)
- *  376  M665 X    delta_tower_angle_trim[A]        (float)
- *  380  M665 Y    delta_tower_angle_trim[B]        (float)
- *  384  M665 Z    delta_tower_angle_trim[C]        (float)
+ * DELTA:                                           40 bytes
+ *  352  M666 XYZ  delta_endstop_adj                (float x3)
+ *  364  M665 R    delta_radius                     (float)
+ *  368  M665 L    delta_diagonal_rod               (float)
+ *  372  M665 S    delta_segments_per_second        (float)
+ *  376  M665 B    delta_calibration_radius         (float)
+ *  380  M665 X    delta_tower_angle_trim[A]        (float)
+ *  384  M665 Y    delta_tower_angle_trim[B]        (float)
+ *  388  M665 Z    delta_tower_angle_trim[C]        (float)
  *
- * Z_DUAL_ENDSTOPS:                                 48 bytes
- *  348  M666 Z    z_endstop_adj                    (float)
- *  ---            dummy data                       (float x11)
+ * [XYZ]_DUAL_ENDSTOPS:                             12 bytes
+ *  352  M666 X    x_endstop_adj                    (float)
+ *  356  M666 Y    y_endstop_adj                    (float)
+ *  360  M666 Z    z_endstop_adj                    (float)
  *
  * ULTIPANEL:                                       6 bytes
- *  396  M145 S0 H lcd_preheat_hotend_temp          (int x2)
- *  400  M145 S0 B lcd_preheat_bed_temp             (int x2)
- *  404  M145 S0 F lcd_preheat_fan_speed            (int x2)
+ *  392  M145 S0 H lcd_preheat_hotend_temp          (int x2)
+ *  396  M145 S0 B lcd_preheat_bed_temp             (int x2)
+ *  400  M145 S0 F lcd_preheat_fan_speed            (int x2)
  *
- * PIDTEMP:                                         66 bytes
- *  408  M301 E0 PIDC  Kp[0], Ki[0], Kd[0], Kc[0]   (float x4)
- *  424  M301 E1 PIDC  Kp[1], Ki[1], Kd[1], Kc[1]   (float x4)
- *  440  M301 E2 PIDC  Kp[2], Ki[2], Kd[2], Kc[2]   (float x4)
- *  456  M301 E3 PIDC  Kp[3], Ki[3], Kd[3], Kc[3]   (float x4)
- *  472  M301 E4 PIDC  Kp[3], Ki[3], Kd[3], Kc[3]   (float x4)
- *  488  M301 L        lpq_len                      (int)
+ * PIDTEMP:                                         82 bytes
+ *  404  M301 E0 PIDC  Kp[0], Ki[0], Kd[0], Kc[0]   (float x4)
+ *  420  M301 E1 PIDC  Kp[1], Ki[1], Kd[1], Kc[1]   (float x4)
+ *  436  M301 E2 PIDC  Kp[2], Ki[2], Kd[2], Kc[2]   (float x4)
+ *  452  M301 E3 PIDC  Kp[3], Ki[3], Kd[3], Kc[3]   (float x4)
+ *  468  M301 E4 PIDC  Kp[3], Ki[3], Kd[3], Kc[3]   (float x4)
+ *  484  M301 L        lpq_len                      (int)
  *
  * PIDTEMPBED:                                      12 bytes
- *  490  M304 PID  thermalManager.bedKp, .bedKi, .bedKd (float x3)
+ *  486  M304 PID  thermalManager.bedKp, .bedKi, .bedKd (float x3)
  *
  * DOGLCD:                                          2 bytes
- *  502  M250 C    lcd_contrast                     (uint16_t)
+ *  498  M250 C    lcd_contrast                     (uint16_t)
  *
  * FWRETRACT:                                       33 bytes
- *  504  M209 S    autoretract_enabled              (bool)
- *  505  M207 S    retract_length                   (float)
- *  509  M207 F    retract_feedrate_mm_s            (float)
- *  513  M207 Z    retract_zlift                    (float)
- *  517  M208 S    retract_recover_length           (float)
- *  521  M208 F    retract_recover_feedrate_mm_s    (float)
- *  525  M207 W    swap_retract_length              (float)
- *  529  M208 W    swap_retract_recover_length      (float)
- *  533  M208 R    swap_retract_recover_feedrate_mm_s (float)
+ *  500  M209 S    autoretract_enabled              (bool)
+ *  501  M207 S    retract_length                   (float)
+ *  505  M207 F    retract_feedrate_mm_s            (float)
+ *  509  M207 Z    retract_zlift                    (float)
+ *  513  M208 S    retract_recover_length           (float)
+ *  517  M208 F    retract_recover_feedrate_mm_s    (float)
+ *  521  M207 W    swap_retract_length              (float)
+ *  525  M208 W    swap_retract_recover_length      (float)
+ *  529  M208 R    swap_retract_recover_feedrate_mm_s (float)
  *
  * Volumetric Extrusion:                            21 bytes
- *  537  M200 D    volumetric_enabled               (bool)
- *  538  M200 T D  filament_size                    (float x5) (T0..3)
+ *  533  M200 D    volumetric_enabled               (bool)
+ *  534  M200 T D  filament_size                    (float x5) (T0..3)
  *
- * HAVE_TMC2130:                                    20 bytes
- *  558  M906 X    Stepper X current                (uint16_t)
- *  560  M906 Y    Stepper Y current                (uint16_t)
- *  562  M906 Z    Stepper Z current                (uint16_t)
- *  564  M906 X2   Stepper X2 current               (uint16_t)
- *  566  M906 Y2   Stepper Y2 current               (uint16_t)
- *  568  M906 Z2   Stepper Z2 current               (uint16_t)
- *  570  M906 E0   Stepper E0 current               (uint16_t)
- *  572  M906 E1   Stepper E1 current               (uint16_t)
- *  574  M906 E2   Stepper E2 current               (uint16_t)
- *  576  M906 E3   Stepper E3 current               (uint16_t)
- *  580  M906 E4   Stepper E4 current               (uint16_t)
+ * HAVE_TMC2130:                                    22 bytes
+ *  554  M906 X    Stepper X current                (uint16_t)
+ *  556  M906 Y    Stepper Y current                (uint16_t)
+ *  558  M906 Z    Stepper Z current                (uint16_t)
+ *  560  M906 X2   Stepper X2 current               (uint16_t)
+ *  562  M906 Y2   Stepper Y2 current               (uint16_t)
+ *  564  M906 Z2   Stepper Z2 current               (uint16_t)
+ *  566  M906 E0   Stepper E0 current               (uint16_t)
+ *  568  M906 E1   Stepper E1 current               (uint16_t)
+ *  570  M906 E2   Stepper E2 current               (uint16_t)
+ *  572  M906 E3   Stepper E3 current               (uint16_t)
+ *  574  M906 E4   Stepper E4 current               (uint16_t)
  *
  * LIN_ADVANCE:                                     8 bytes
- *  584  M900 K    extruder_advance_k               (float)
- *  588  M900 WHD  advance_ed_ratio                 (float)
+ *  576  M900 K    extruder_advance_k               (float)
+ *  580  M900 WHD  advance_ed_ratio                 (float)
  *
  * HAS_MOTOR_CURRENT_PWM:
- *  592  M907 X    Stepper XY current               (uint32_t)
- *  596  M907 Z    Stepper Z current                (uint32_t)
- *  600  M907 E    Stepper E current                (uint32_t)
+ *  584  M907 X    Stepper XY current               (uint32_t)
+ *  588  M907 Z    Stepper Z current                (uint32_t)
+ *  592  M907 E    Stepper E current                (uint32_t)
  *
- *  604                                Minimum end-point
- * 1925 (604 + 36 + 9 + 288 + 988)     Maximum end-point
+ *  596                                Minimum end-point
+ * 1917 (596 + 36 + 9 + 288 + 988)     Maximum end-point
  *
  * ========================================================================
  * meshes_begin (between max and min end-point, directly above)
@@ -209,8 +210,8 @@ MarlinSettings settings;
 #endif
 
 /**
- * Post-process after Retrieve or Reset
- */
+* Post-process after Retrieve or Reset
+*/
 void MarlinSettings::postprocess() {
   // steps per s2 needs to be updated to agree with units per s2
   planner.reset_acceleration_rates();
@@ -448,7 +449,7 @@ void MarlinSettings::postprocess() {
       EEPROM_WRITE(storage_slot);
     #endif // AUTO_BED_LEVELING_UBL
 
-    // 10 floats for DELTA / Z_DUAL_ENDSTOPS
+    // 10 floats for DELTA / [XYZ]_DUAL_ENDSTOPS
     #if ENABLED(DELTA)
       EEPROM_WRITE(delta_endstop_adj);         // 3 floats
       EEPROM_WRITE(delta_radius);              // 1 float
@@ -456,15 +457,33 @@ void MarlinSettings::postprocess() {
       EEPROM_WRITE(delta_segments_per_second); // 1 float
       EEPROM_WRITE(delta_calibration_radius);  // 1 float
       EEPROM_WRITE(delta_tower_angle_trim);    // 3 floats
+
+    #elif ENABLED(X_DUAL_ENDSTOPS) || ENABLED(Y_DUAL_ENDSTOPS) || ENABLED(Z_DUAL_ENDSTOPS)
+      // Write dual endstops in X, Y, Z order. Unused = 0.0
       dummy = 0.0f;
-      for (uint8_t q = 2; q--;) EEPROM_WRITE(dummy);
-    #elif ENABLED(Z_DUAL_ENDSTOPS)
-      EEPROM_WRITE(z_endstop_adj);             // 1 float
-      dummy = 0.0f;
-      for (uint8_t q = 11; q--;) EEPROM_WRITE(dummy);
+      #if ENABLED(X_DUAL_ENDSTOPS)
+        EEPROM_WRITE(x_endstop_adj);             // 1 float
+      #else
+        EEPROM_WRITE(dummy);
+      #endif
+
+      #if ENABLED(Y_DUAL_ENDSTOPS)
+        EEPROM_WRITE(y_endstop_adj);             // 1 float
+      #else
+        EEPROM_WRITE(dummy);
+      #endif
+
+      #if ENABLED(Z_DUAL_ENDSTOPS)
+        EEPROM_WRITE(z_endstop_adj);             // 1 float
+      #else
+        EEPROM_WRITE(dummy);
+      #endif
+
+      for (uint8_t q = 7; q--;) EEPROM_WRITE(dummy);
+
     #else
       dummy = 0.0f;
-      for (uint8_t q = 12; q--;) EEPROM_WRITE(dummy);
+      for (uint8_t q = 10; q--;) EEPROM_WRITE(dummy);
     #endif
 
     #if DISABLED(ULTIPANEL)
@@ -845,13 +864,31 @@ void MarlinSettings::postprocess() {
         EEPROM_READ(delta_tower_angle_trim);    // 3 floats
         dummy = 0.0f;
         for (uint8_t q=2; q--;) EEPROM_READ(dummy);
-      #elif ENABLED(Z_DUAL_ENDSTOPS)
-        EEPROM_READ(z_endstop_adj);
-        dummy = 0.0f;
-        for (uint8_t q=11; q--;) EEPROM_READ(dummy);
+
+      #elif ENABLED(X_DUAL_ENDSTOPS) || ENABLED(Y_DUAL_ENDSTOPS) || ENABLED(Z_DUAL_ENDSTOPS)
+
+        #if ENABLED(X_DUAL_ENDSTOPS)
+          EEPROM_READ(x_endstop_adj);             // 1 float
+        #else
+          EEPROM_READ(dummy);
+        #endif
+        #if ENABLED(Y_DUAL_ENDSTOPS)
+          EEPROM_READ(y_endstop_adj);             // 1 float
+        #else
+          EEPROM_READ(dummy);
+        #endif
+        #if ENABLED(Z_DUAL_ENDSTOPS)
+          EEPROM_READ(z_endstop_adj);             // 1 float
+        #else
+          EEPROM_READ(dummy);
+        #endif
+
+        for (uint8_t q=7; q--;) EEPROM_READ(dummy);
+
       #else
-        dummy = 0.0f;
-        for (uint8_t q=12; q--;) EEPROM_READ(dummy);
+
+        for (uint8_t q=10; q--;) EEPROM_READ(dummy);
+
       #endif
 
       #if DISABLED(ULTIPANEL)
@@ -1234,15 +1271,35 @@ void MarlinSettings::reset() {
     COPY(delta_tower_angle_trim, dta);
     home_offset[Z_AXIS] = 0;
 
-  #elif ENABLED(Z_DUAL_ENDSTOPS)
+  #elif ENABLED(X_DUAL_ENDSTOPS) || ENABLED(Y_DUAL_ENDSTOPS) || ENABLED(Z_DUAL_ENDSTOPS)
 
-    z_endstop_adj =
-      #ifdef Z_DUAL_ENDSTOPS_ADJUSTMENT
-        Z_DUAL_ENDSTOPS_ADJUSTMENT
-      #else
-        0
-      #endif
-    ;
+    #if ENABLED(X_DUAL_ENDSTOPS)
+      x_endstop_adj = (
+        #ifdef X_DUAL_ENDSTOPS_ADJUSTMENT
+          X_DUAL_ENDSTOPS_ADJUSTMENT
+        #else
+          0
+        #endif
+      );
+    #endif
+    #if ENABLED(Y_DUAL_ENDSTOPS)
+      y_endstop_adj = (
+        #ifdef Y_DUAL_ENDSTOPS_ADJUSTMENT
+          Y_DUAL_ENDSTOPS_ADJUSTMENT
+        #else
+          0
+        #endif
+      );
+    #endif
+    #if ENABLED(Z_DUAL_ENDSTOPS)
+      z_endstop_adj = (
+        #ifdef Z_DUAL_ENDSTOPS_ADJUSTMENT
+          Z_DUAL_ENDSTOPS_ADJUSTMENT
+        #else
+          0
+        #endif
+      );
+    #endif
 
   #endif
 
@@ -1656,13 +1713,24 @@ void MarlinSettings::reset() {
       SERIAL_ECHOPAIR(" Y", LINEAR_UNIT(delta_tower_angle_trim[B_AXIS]));
       SERIAL_ECHOPAIR(" Z", LINEAR_UNIT(delta_tower_angle_trim[C_AXIS]));
       SERIAL_EOL();
-    #elif ENABLED(Z_DUAL_ENDSTOPS)
+
+    #elif ENABLED(X_DUAL_ENDSTOPS) || ENABLED(Y_DUAL_ENDSTOPS) || ENABLED(Z_DUAL_ENDSTOPS)
       if (!forReplay) {
         CONFIG_ECHO_START;
-        SERIAL_ECHOLNPGM("Z2 Endstop adjustment:");
+        SERIAL_ECHOLNPGM("Endstop adjustment:");
       }
       CONFIG_ECHO_START;
-      SERIAL_ECHOLNPAIR("  M666 Z", LINEAR_UNIT(z_endstop_adj));
+      SERIAL_ECHOPGM("  M666");
+      #if ENABLED(X_DUAL_ENDSTOPS)
+        SERIAL_ECHOPAIR(" X", LINEAR_UNIT(x_endstop_adj));
+      #endif
+      #if ENABLED(Y_DUAL_ENDSTOPS)
+        SERIAL_ECHOPAIR(" Y", LINEAR_UNIT(y_endstop_adj));
+      #endif
+      #if ENABLED(Z_DUAL_ENDSTOPS)
+        SERIAL_ECHOPAIR(" Z", LINEAR_UNIT(z_endstop_adj));
+      #endif
+      SERIAL_EOL();
     #endif // DELTA
 
     #if ENABLED(ULTIPANEL)

Marlin/endstop_interrupts.h

@@ -170,6 +170,46 @@ void setup_endstop_interrupts( void ) {
     #endif
   #endif
 
+  #if HAS_X2_MAX
+    #if (digitalPinToInterrupt(X2_MAX_PIN) != NOT_AN_INTERRUPT)
+      attachInterrupt(digitalPinToInterrupt(X2_MAX_PIN), endstop_ISR, CHANGE);
+    #else
+      // Not all used endstop/probe -pins can raise interrupts. Please deactivate ENDSTOP_INTERRUPTS or change the pin configuration!
+      static_assert(digitalPinToPCICR(X2_MAX_PIN) != NULL, "X2_MAX_PIN is not interrupt-capable");
+      pciSetup(X2_MAX_PIN);
+    #endif
+  #endif
+
+  #if HAS_X2_MIN
+    #if (digitalPinToInterrupt(X2_MIN_PIN) != NOT_AN_INTERRUPT)
+      attachInterrupt(digitalPinToInterrupt(X2_MIN_PIN), endstop_ISR, CHANGE);
+    #else
+      // Not all used endstop/probe -pins can raise interrupts. Please deactivate ENDSTOP_INTERRUPTS or change the pin configuration!
+      static_assert(digitalPinToPCICR(X2_MIN_PIN) != NULL, "X2_MIN_PIN is not interrupt-capable");
+      pciSetup(X2_MIN_PIN);
+    #endif
+  #endif
+
+  #if HAS_Y2_MAX
+    #if (digitalPinToInterrupt(Y2_MAX_PIN) != NOT_AN_INTERRUPT)
+      attachInterrupt(digitalPinToInterrupt(Y2_MAX_PIN), endstop_ISR, CHANGE);
+    #else
+      // Not all used endstop/probe -pins can raise interrupts. Please deactivate ENDSTOP_INTERRUPTS or change the pin configuration!
+      static_assert(digitalPinToPCICR(Y2_MAX_PIN) != NULL, "Y2_MAX_PIN is not interrupt-capable");
+      pciSetup(Y2_MAX_PIN);
+    #endif
+  #endif
+
+  #if HAS_Y2_MIN
+    #if (digitalPinToInterrupt(Y2_MIN_PIN) != NOT_AN_INTERRUPT)
+      attachInterrupt(digitalPinToInterrupt(Y2_MIN_PIN), endstop_ISR, CHANGE);
+    #else
+      // Not all used endstop/probe -pins can raise interrupts. Please deactivate ENDSTOP_INTERRUPTS or change the pin configuration!
+      static_assert(digitalPinToPCICR(Y2_MIN_PIN) != NULL, "Y2_MIN_PIN is not interrupt-capable");
+      pciSetup(Y2_MIN_PIN);
+    #endif
+  #endif
+
   #if HAS_Z2_MAX
     #if (digitalPinToInterrupt(Z2_MAX_PIN) != NOT_AN_INTERRUPT)
       attachInterrupt(digitalPinToInterrupt(Z2_MAX_PIN), endstop_ISR, CHANGE);

Marlin/endstops.cpp

@@ -41,7 +41,7 @@ Endstops endstops;
 bool Endstops::enabled, Endstops::enabled_globally; // Initialized by settings.load()
 volatile char Endstops::endstop_hit_bits; // use X_MIN, Y_MIN, Z_MIN and Z_MIN_PROBE as BIT value
 
-#if ENABLED(Z_DUAL_ENDSTOPS)
+#if ENABLED(X_DUAL_ENDSTOPS) || ENABLED(Y_DUAL_ENDSTOPS) || ENABLED(Z_DUAL_ENDSTOPS)
   uint16_t
 #else
   byte
@@ -67,6 +67,14 @@ void Endstops::init() {
     #endif
   #endif
 
+  #if HAS_X2_MIN
+    #if ENABLED(ENDSTOPPULLUP_XMIN)
+      SET_INPUT_PULLUP(X2_MIN_PIN);
+    #else
+      SET_INPUT(X2_MIN_PIN);
+    #endif
+  #endif
+
   #if HAS_Y_MIN
     #if ENABLED(ENDSTOPPULLUP_YMIN)
       SET_INPUT_PULLUP(Y_MIN_PIN);
@@ -75,6 +83,14 @@ void Endstops::init() {
     #endif
   #endif
 
+  #if HAS_Y2_MIN
+    #if ENABLED(ENDSTOPPULLUP_YMIN)
+      SET_INPUT_PULLUP(Y2_MIN_PIN);
+    #else
+      SET_INPUT(Y2_MIN_PIN);
+    #endif
+  #endif
+
   #if HAS_Z_MIN
     #if ENABLED(ENDSTOPPULLUP_ZMIN)
       SET_INPUT_PULLUP(Z_MIN_PIN);
@@ -99,6 +115,14 @@ void Endstops::init() {
     #endif
   #endif
 
+  #if HAS_X2_MAX
+    #if ENABLED(ENDSTOPPULLUP_XMAX)
+      SET_INPUT_PULLUP(X2_MAX_PIN);
+    #else
+      SET_INPUT(X2_MAX_PIN);
+    #endif
+  #endif
+
   #if HAS_Y_MAX
     #if ENABLED(ENDSTOPPULLUP_YMAX)
       SET_INPUT_PULLUP(Y_MAX_PIN);
@@ -107,6 +131,14 @@ void Endstops::init() {
     #endif
   #endif
 
+  #if HAS_Y2_MAX
+    #if ENABLED(ENDSTOPPULLUP_YMAX)
+      SET_INPUT_PULLUP(Y2_MAX_PIN);
+    #else
+      SET_INPUT(Y2_MAX_PIN);
+    #endif
+  #endif
+
   #if HAS_Z_MAX
     #if ENABLED(ENDSTOPPULLUP_ZMAX)
       SET_INPUT_PULLUP(Z_MAX_PIN);
@@ -185,37 +217,45 @@ void Endstops::report_state() {
 
 void Endstops::M119() {
   SERIAL_PROTOCOLLNPGM(MSG_M119_REPORT);
+  #define ES_REPORT(AXIS) do{ \
+    SERIAL_PROTOCOLPGM(MSG_##AXIS); \
+    SERIAL_PROTOCOLLN(((READ(AXIS##_PIN)^AXIS##_ENDSTOP_INVERTING) ? MSG_ENDSTOP_HIT : MSG_ENDSTOP_OPEN)); \
+  }while(0)
   #if HAS_X_MIN
-    SERIAL_PROTOCOLPGM(MSG_X_MIN);
-    SERIAL_PROTOCOLLN(((READ(X_MIN_PIN)^X_MIN_ENDSTOP_INVERTING) ? MSG_ENDSTOP_HIT : MSG_ENDSTOP_OPEN));
+    ES_REPORT(X_MIN);
+  #endif
+  #if HAS_X2_MIN
+    ES_REPORT(X2_MIN);
   #endif
   #if HAS_X_MAX
-    SERIAL_PROTOCOLPGM(MSG_X_MAX);
-    SERIAL_PROTOCOLLN(((READ(X_MAX_PIN)^X_MAX_ENDSTOP_INVERTING) ? MSG_ENDSTOP_HIT : MSG_ENDSTOP_OPEN));
+    ES_REPORT(X_MAX);
+  #endif
+  #if HAS_X2_MAX
+    ES_REPORT(X2_MAX);
   #endif
   #if HAS_Y_MIN
-    SERIAL_PROTOCOLPGM(MSG_Y_MIN);
-    SERIAL_PROTOCOLLN(((READ(Y_MIN_PIN)^Y_MIN_ENDSTOP_INVERTING) ? MSG_ENDSTOP_HIT : MSG_ENDSTOP_OPEN));
+    ES_REPORT(Y_MIN);
+  #endif
+  #if HAS_Y2_MIN
+    ES_REPORT(Y2_MIN);
   #endif
   #if HAS_Y_MAX
-    SERIAL_PROTOCOLPGM(MSG_Y_MAX);
-    SERIAL_PROTOCOLLN(((READ(Y_MAX_PIN)^Y_MAX_ENDSTOP_INVERTING) ? MSG_ENDSTOP_HIT : MSG_ENDSTOP_OPEN));
+    ES_REPORT(Y_MAX);
+  #endif
+  #if HAS_Y2_MAX
+    ES_REPORT(Y2_MAX);
   #endif
   #if HAS_Z_MIN
-    SERIAL_PROTOCOLPGM(MSG_Z_MIN);
-    SERIAL_PROTOCOLLN(((READ(Z_MIN_PIN)^Z_MIN_ENDSTOP_INVERTING) ? MSG_ENDSTOP_HIT : MSG_ENDSTOP_OPEN));
+    ES_REPORT(Z_MIN);
   #endif
   #if HAS_Z2_MIN
-    SERIAL_PROTOCOLPGM(MSG_Z2_MIN);
-    SERIAL_PROTOCOLLN(((READ(Z2_MIN_PIN)^Z2_MIN_ENDSTOP_INVERTING) ? MSG_ENDSTOP_HIT : MSG_ENDSTOP_OPEN));
+    ES_REPORT(Z2_MIN);
   #endif
   #if HAS_Z_MAX
-    SERIAL_PROTOCOLPGM(MSG_Z_MAX);
-    SERIAL_PROTOCOLLN(((READ(Z_MAX_PIN)^Z_MAX_ENDSTOP_INVERTING) ? MSG_ENDSTOP_HIT : MSG_ENDSTOP_OPEN));
+    ES_REPORT(Z_MAX);
   #endif
   #if HAS_Z2_MAX
-    SERIAL_PROTOCOLPGM(MSG_Z2_MAX);
-    SERIAL_PROTOCOLLN(((READ(Z2_MAX_PIN)^Z2_MAX_ENDSTOP_INVERTING) ? MSG_ENDSTOP_HIT : MSG_ENDSTOP_OPEN));
+    ES_REPORT(Z2_MAX);
   #endif
   #if ENABLED(Z_MIN_PROBE_ENDSTOP)
     SERIAL_PROTOCOLPGM(MSG_Z_PROBE);
@@ -227,9 +267,27 @@ void Endstops::M119() {
   #endif
 } // Endstops::M119
 
+#if ENABLED(X_DUAL_ENDSTOPS)
+  void Endstops::test_dual_x_endstops(const EndstopEnum es1, const EndstopEnum es2) {
+    byte x_test = TEST_ENDSTOP(es1) | (TEST_ENDSTOP(es2) << 1); // bit 0 for X, bit 1 for X2
+    if (x_test && stepper.current_block->steps[X_AXIS] > 0) {
+      SBI(endstop_hit_bits, X_MIN);
+      if (!stepper.performing_homing || (x_test == 0x3))  //if not performing home or if both endstops were trigged during homing...
+        stepper.kill_current_block();
+    }
+  }
+#endif
+#if ENABLED(Y_DUAL_ENDSTOPS)
+  void Endstops::test_dual_y_endstops(const EndstopEnum es1, const EndstopEnum es2) {
+    byte y_test = TEST_ENDSTOP(es1) | (TEST_ENDSTOP(es2) << 1); // bit 0 for Y, bit 1 for Y2
+    if (y_test && stepper.current_block->steps[Y_AXIS] > 0) {
+      SBI(endstop_hit_bits, Y_MIN);
+      if (!stepper.performing_homing || (y_test == 0x3))  //if not performing home or if both endstops were trigged during homing...
+        stepper.kill_current_block();
+    }
+  }
+#endif
 #if ENABLED(Z_DUAL_ENDSTOPS)
-
-  // Pass the result of the endstop test
   void Endstops::test_dual_z_endstops(const EndstopEnum es1, const EndstopEnum es2) {
     byte z_test = TEST_ENDSTOP(es1) | (TEST_ENDSTOP(es2) << 1); // bit 0 for Z, bit 1 for Z2
     if (z_test && stepper.current_block->steps[Z_AXIS] > 0) {
@@ -238,7 +296,6 @@ void Endstops::M119() {
         stepper.kill_current_block();
     }
   }
-
 #endif
 
 // Check endstops - Called from ISR!
@@ -357,18 +414,36 @@ void Endstops::update() {
   /**
    * Check and update endstops according to conditions
    */
-
   if (X_MOVE_TEST) {
-    if (stepper.motor_direction(X_AXIS_HEAD)) {
-      if (X_MIN_TEST) { // -direction
-        #if HAS_X_MIN
-          UPDATE_ENDSTOP(X, MIN);
+    if (stepper.motor_direction(X_AXIS_HEAD)) { // -direction
+      #if HAS_X_MIN
+        #if ENABLED(X_DUAL_ENDSTOPS)
+          UPDATE_ENDSTOP_BIT(X, MIN);
+          #if HAS_X2_MIN
+            UPDATE_ENDSTOP_BIT(X2, MIN);
+          #else
+            COPY_BIT(current_endstop_bits, X_MIN, X2_MIN);
+          #endif
+          test_dual_x_endstops(X_MIN, X2_MIN);
+        #else
+          if (X_MIN_TEST) UPDATE_ENDSTOP(X, MIN);
         #endif
-      }
+      #endif
     }
-    else if (X_MAX_TEST) { // +direction
+    else { // +direction
       #if HAS_X_MAX
-        UPDATE_ENDSTOP(X, MAX);
+        #if ENABLED(X_DUAL_ENDSTOPS)
+          UPDATE_ENDSTOP_BIT(X, MAX);
+          #if HAS_X2_MAX
+            UPDATE_ENDSTOP_BIT(X2, MAX);
+          #else
+            COPY_BIT(current_endstop_bits, X_MAX, X2_MAX);
+          #endif
+          test_dual_x_endstops(X_MAX, X2_MAX);
+        #else
+          if (X_MIN_TEST) UPDATE_ENDSTOP(X, MAX);
+        #endif
+
       #endif
     }
   }
@@ -376,12 +451,32 @@ void Endstops::update() {
   if (Y_MOVE_TEST) {
     if (stepper.motor_direction(Y_AXIS_HEAD)) { // -direction
       #if HAS_Y_MIN
-        UPDATE_ENDSTOP(Y, MIN);
+        #if ENABLED(Y_DUAL_ENDSTOPS)
+          UPDATE_ENDSTOP_BIT(Y, MIN);
+          #if HAS_Y2_MIN
+            UPDATE_ENDSTOP_BIT(Y2, MIN);
+          #else
+            COPY_BIT(current_endstop_bits, Y_MIN, Y2_MIN);
+          #endif
+          test_dual_y_endstops(Y_MIN, Y2_MIN);
+        #else
+          UPDATE_ENDSTOP(Y, MIN);
+        #endif
       #endif
     }
     else { // +direction
       #if HAS_Y_MAX
-        UPDATE_ENDSTOP(Y, MAX);
+        #if ENABLED(Y_DUAL_ENDSTOPS)
+          UPDATE_ENDSTOP_BIT(Y, MAX);
+          #if HAS_Y2_MAX
+            UPDATE_ENDSTOP_BIT(Y2, MAX);
+          #else
+            COPY_BIT(current_endstop_bits, Y_MAX, Y2_MAX);
+          #endif
+          test_dual_y_endstops(Y_MAX, Y2_MAX);
+        #else
+          UPDATE_ENDSTOP(Y, MAX);
+        #endif
       #endif
     }
   }
@@ -390,27 +485,21 @@ void Endstops::update() {
     if (stepper.motor_direction(Z_AXIS_HEAD)) { // Z -direction. Gantry down, bed up.
       #if HAS_Z_MIN
         #if ENABLED(Z_DUAL_ENDSTOPS)
-
           UPDATE_ENDSTOP_BIT(Z, MIN);
           #if HAS_Z2_MIN
             UPDATE_ENDSTOP_BIT(Z2, MIN);
           #else
             COPY_BIT(current_endstop_bits, Z_MIN, Z2_MIN);
           #endif
-
           test_dual_z_endstops(Z_MIN, Z2_MIN);
-
-        #else // !Z_DUAL_ENDSTOPS
-
+        #else
           #if ENABLED(Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN)
             if (z_probe_enabled) UPDATE_ENDSTOP(Z, MIN);
           #else
             UPDATE_ENDSTOP(Z, MIN);
           #endif
-
-        #endif // !Z_DUAL_ENDSTOPS
-
-      #endif // HAS_Z_MIN
+        #endif
+      #endif
 
       // When closing the gap check the enabled probe
       #if ENABLED(Z_MIN_PROBE_ENDSTOP)
@@ -422,27 +511,21 @@ void Endstops::update() {
     }
     else { // Z +direction. Gantry up, bed down.
       #if HAS_Z_MAX
-
         // Check both Z dual endstops
         #if ENABLED(Z_DUAL_ENDSTOPS)
-
           UPDATE_ENDSTOP_BIT(Z, MAX);
           #if HAS_Z2_MAX
             UPDATE_ENDSTOP_BIT(Z2, MAX);
           #else
             COPY_BIT(current_endstop_bits, Z_MAX, Z2_MAX);
           #endif
-
           test_dual_z_endstops(Z_MAX, Z2_MAX);
-
         // If this pin is not hijacked for the bed probe
         // then it belongs to the Z endstop
         #elif DISABLED(Z_MIN_PROBE_ENDSTOP) || Z_MAX_PIN != Z_MIN_PROBE_PIN
-
           UPDATE_ENDSTOP(Z, MAX);
-
-        #endif // !Z_MIN_PROBE_PIN...
-      #endif // Z_MAX_PIN
+        #endif
+      #endif
     }
   }
 

Marlin/endstops.h

@@ -36,7 +36,7 @@ class Endstops {
     static bool enabled, enabled_globally;
     static volatile char endstop_hit_bits; // use X_MIN, Y_MIN, Z_MIN and Z_MIN_PROBE as BIT value
 
-    #if ENABLED(Z_DUAL_ENDSTOPS)
+    #if ENABLED(X_DUAL_ENDSTOPS) || ENABLED(Y_DUAL_ENDSTOPS) || ENABLED(Z_DUAL_ENDSTOPS)
       static uint16_t
     #else
       static byte
@@ -85,6 +85,12 @@ class Endstops {
 
   private:
 
+    #if ENABLED(X_DUAL_ENDSTOPS)
+      static void test_dual_x_endstops(const EndstopEnum es1, const EndstopEnum es2);
+    #endif
+    #if ENABLED(Y_DUAL_ENDSTOPS)
+      static void test_dual_y_endstops(const EndstopEnum es1, const EndstopEnum es2);
+    #endif
     #if ENABLED(Z_DUAL_ENDSTOPS)
       static void test_dual_z_endstops(const EndstopEnum es1, const EndstopEnum es2);
     #endif

Marlin/enum.h

@@ -93,6 +93,10 @@ enum EndstopEnum {
   X_MAX,
   Y_MAX,
   Z_MAX,
+  X2_MIN,
+  X2_MAX,
+  Y2_MIN,
+  Y2_MAX,
   Z2_MIN,
   Z2_MAX
 };

Marlin/example_configurations/AlephObjects/TAZ4/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/Anet/A6/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/Anet/A8/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/BQ/Hephestos/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/BQ/Hephestos_2/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 #define DIGIPOT_MOTOR_CURRENT { 150, 170, 180, 190, 180 }   // Values 0-255 (bq ZUM Mega 3D (default): X = 150 [~1.17A]; Y = 170 [~1.33A]; Z = 180 [~1.41A]; E0 = 190 [~1.49A])
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }      // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/BQ/WITBOX/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/Cartesio/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/Creality/CR-10/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/Felix/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/FolgerTech/i3-2020/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/Infitary/i3-M508/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 #define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/Malyan/M150/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/Micromake/C1/enhanced/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/RigidBot/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/SCARA/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/Sanguinololu/Configuration_adv.h

@@ -246,6 +246,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -423,8 +467,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/TinyBoy2/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/Velleman/K8200/Configuration_adv.h

@@ -270,6 +270,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -447,8 +491,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/Velleman/K8400/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/delta/FLSUN/auto_calibrate/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -436,8 +480,21 @@
 #define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/delta/FLSUN/kossel_mini/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -436,8 +480,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/delta/generic/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -436,8 +480,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/delta/kossel_mini/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -436,8 +480,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/delta/kossel_pro/Configuration_adv.h

@@ -262,6 +262,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -441,8 +485,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/delta/kossel_xl/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -436,8 +480,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/gCreate/gMax1.5+/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/makibox/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 4 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/tvrrug/Round2/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.
@@ -434,8 +478,21 @@
 //#define DIGIPOT_MOTOR_CURRENT { 135,135,135,135,135 }   // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
 //#define DAC_MOTOR_CURRENT_DEFAULT { 70, 80, 90, 80 }    // Default drive percent - X, Y, Z, E axis
 
-// Uncomment to enable an I2C based DIGIPOT like on the Azteeg X3 Pro
+// Use an I2C based DIGIPOT (e.g., Azteeg X3 Pro)
 //#define DIGIPOT_I2C
+#if ENABLED(DIGIPOT_I2C) && !defined(DIGIPOT_I2C_ADDRESS_A)
+  /**
+   * Common slave addresses:
+   *
+   *                    A   (A shifted)   B   (B shifted)  IC
+   * Smoothie          0x2C (0x58)       0x2D (0x5A)       MCP4451
+   * AZTEEG_X3_PRO     0x2C (0x58)       0x2E (0x5C)       MCP4451
+   * MIGHTYBOARD_REVE  0x2F (0x5E)                         MCP4018
+   */
+  #define DIGIPOT_I2C_ADDRESS_A 0x2C  // unshifted slave address for first DIGIPOT
+  #define DIGIPOT_I2C_ADDRESS_B 0x2D  // unshifted slave address for second DIGIPOT
+#endif
+
 //#define DIGIPOT_MCP4018          // Requires library from https://github.com/stawel/SlowSoftI2CMaster
 #define DIGIPOT_I2C_NUM_CHANNELS 8 // 5DPRINT: 4     AZTEEG_X3_PRO: 8
 // Actual motor currents in Amps, need as many here as DIGIPOT_I2C_NUM_CHANNELS

Marlin/example_configurations/wt150/Configuration_adv.h

@@ -257,6 +257,50 @@
 
 //#define Z_LATE_ENABLE // Enable Z the last moment. Needed if your Z driver overheats.
 
+/**
+ * Dual Steppers / Dual Endstops
+ *
+ * This section will allow you to use extra E drivers to drive a second motor for X, Y, or Z axes.
+ *
+ * For example, set X_DUAL_STEPPER_DRIVERS setting to use a second motor. If the motors need to
+ * spin in opposite directions set INVERT_X2_VS_X_DIR. If the second motor needs its own endstop
+ * set X_DUAL_ENDSTOPS. This can adjust for "racking." Use X2_USE_ENDSTOP to set the endstop plug
+ * that should be used for the second endstop. Extra endstops will appear in the output of 'M119'.
+ *
+ * Use X_DUAL_ENDSTOP_ADJUSTMENT to adjust for mechanical imperfection. After homing both motors
+ * this offset is applied to the X2 motor. To find the offset home the X axis, and measure the error
+ * in X2. Dual endstop offsets can be set at runtime with 'M666 X<offset> Y<offset> Z<offset>'.
+ */
+
+//#define X_DUAL_STEPPER_DRIVERS
+#if ENABLED(X_DUAL_STEPPER_DRIVERS)
+  #define INVERT_X2_VS_X_DIR true   // Set 'true' if X motors should rotate in opposite directions
+  //#define X_DUAL_ENDSTOPS
+  #if ENABLED(X_DUAL_ENDSTOPS)
+    #define X2_USE_ENDSTOP _XMAX_
+    #define X_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Y_DUAL_STEPPER_DRIVERS
+#if ENABLED(Y_DUAL_STEPPER_DRIVERS)
+  #define INVERT_Y2_VS_Y_DIR true   // Set 'true' if Y motors should rotate in opposite directions
+  //#define Y_DUAL_ENDSTOPS
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y2_USE_ENDSTOP _YMAX_
+    #define Y_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
+//#define Z_DUAL_STEPPER_DRIVERS
+#if ENABLED(Z_DUAL_STEPPER_DRIVERS)
+  //#define Z_DUAL_ENDSTOPS
+  #if ENABLED(Z_DUAL_ENDSTOPS)
+    #define Z2_USE_ENDSTOP _XMAX_
+    #define Z_DUAL_ENDSTOPS_ADJUSTMENT  0
+  #endif
+#endif
+
 // Dual X Steppers
 // Uncomment this option to drive two X axis motors.
 // The next unused E driver will be assigned to the second X stepper.

Marlin/language.h

@@ -150,8 +150,12 @@
 #define MSG_ACTIVE_EXTRUDER                 "Active Extruder: "
 #define MSG_X_MIN                           "x_min: "
 #define MSG_X_MAX                           "x_max: "
+#define MSG_X2_MIN                          "x2_min: "
+#define MSG_X2_MAX                          "x2_max: "
 #define MSG_Y_MIN                           "y_min: "
 #define MSG_Y_MAX                           "y_max: "
+#define MSG_Y2_MIN                          "y2_min: "
+#define MSG_Y2_MAX                          "y2_max: "
 #define MSG_Z_MIN                           "z_min: "
 #define MSG_Z_MAX                           "z_max: "
 #define MSG_Z2_MIN                          "z2_min: "

Marlin/macros.h

@@ -28,6 +28,13 @@
 #define ABC  3
 #define XYZ  3
 
+#define _XMIN_ 100
+#define _YMIN_ 200
+#define _ZMIN_ 300
+#define _XMAX_ 101
+#define _YMAX_ 201
+#define _ZMAX_ 301
+
 #define FORCE_INLINE __attribute__((always_inline)) inline
 #define _UNUSED      __attribute__((unused))
 #define _O0          __attribute__((optimize("O0")))

Marlin/stepper.cpp

@@ -72,7 +72,7 @@ block_t* Stepper::current_block = NULL;  // A pointer to the block currently bei
   bool Stepper::abort_on_endstop_hit = false;
 #endif
 
-#if ENABLED(Z_DUAL_ENDSTOPS)
+#if ENABLED(X_DUAL_ENDSTOPS) || ENABLED(Y_DUAL_ENDSTOPS) || ENABLED(Z_DUAL_ENDSTOPS)
   bool Stepper::performing_homing = false;
 #endif
 
@@ -85,9 +85,14 @@ block_t* Stepper::current_block = NULL;  // A pointer to the block currently bei
 uint8_t Stepper::last_direction_bits = 0;        // The next stepping-bits to be output
 uint16_t Stepper::cleaning_buffer_counter = 0;
 
+#if ENABLED(X_DUAL_ENDSTOPS)
+  bool Stepper::locked_x_motor = false, Stepper::locked_x2_motor = false;
+#endif
+#if ENABLED(Y_DUAL_ENDSTOPS)
+  bool Stepper::locked_y_motor = false, Stepper::locked_y2_motor = false;
+#endif
 #if ENABLED(Z_DUAL_ENDSTOPS)
-  bool Stepper::locked_z_motor = false;
-  bool Stepper::locked_z2_motor = false;
+  bool Stepper::locked_z_motor = false, Stepper::locked_z2_motor = false;
 #endif
 
 long Stepper::counter_X = 0,
@@ -142,26 +147,54 @@ unsigned short Stepper::OCR1A_nominal;
 
 volatile long Stepper::endstops_trigsteps[XYZ];
 
+#if ENABLED(X_DUAL_ENDSTOPS) || ENABLED(Y_DUAL_ENDSTOPS) || ENABLED(Z_DUAL_ENDSTOPS)
+  #define LOCKED_X_MOTOR  locked_x_motor
+  #define LOCKED_Y_MOTOR  locked_y_motor
+  #define LOCKED_Z_MOTOR  locked_z_motor
+  #define LOCKED_X2_MOTOR locked_x2_motor
+  #define LOCKED_Y2_MOTOR locked_y2_motor
+  #define LOCKED_Z2_MOTOR locked_z2_motor
+  #define DUAL_ENDSTOP_APPLY_STEP(AXIS,v)                                                                                                             \
+    if (performing_homing) {                                                                                                                          \
+      if (AXIS##_HOME_DIR < 0) {                                                                                                                      \
+        if (!(TEST(endstops.old_endstop_bits, AXIS##_MIN) && (count_direction[AXIS##_AXIS] < 0)) && !LOCKED_##AXIS##_MOTOR) AXIS##_STEP_WRITE(v);     \
+        if (!(TEST(endstops.old_endstop_bits, AXIS##2_MIN) && (count_direction[AXIS##_AXIS] < 0)) && !LOCKED_##AXIS##2_MOTOR) AXIS##2_STEP_WRITE(v);  \
+      }                                                                                                                                               \
+      else {                                                                                                                                          \
+        if (!(TEST(endstops.old_endstop_bits, AXIS##_MAX) && (count_direction[AXIS##_AXIS] > 0)) && !LOCKED_##AXIS##_MOTOR) AXIS##_STEP_WRITE(v);     \
+        if (!(TEST(endstops.old_endstop_bits, AXIS##2_MAX) && (count_direction[AXIS##_AXIS] > 0)) && !LOCKED_##AXIS##2_MOTOR) AXIS##2_STEP_WRITE(v);  \
+      }                                                                                                                                               \
+    }                                                                                                                                                 \
+    else {                                                                                                                                            \
+      AXIS##_STEP_WRITE(v);                                                                                                                           \
+      AXIS##2_STEP_WRITE(v);                                                                                                                          \
+    }
+#endif
+
 #if ENABLED(X_DUAL_STEPPER_DRIVERS)
   #define X_APPLY_DIR(v,Q) do{ X_DIR_WRITE(v); X2_DIR_WRITE((v) != INVERT_X2_VS_X_DIR); }while(0)
-  #define X_APPLY_STEP(v,Q) do{ X_STEP_WRITE(v); X2_STEP_WRITE(v); }while(0)
-#elif ENABLED(DUAL_X_CARRIAGE)
-  #define X_APPLY_DIR(v,ALWAYS) \
-    if (extruder_duplication_enabled || ALWAYS) { \
-      X_DIR_WRITE(v); \
-      X2_DIR_WRITE(v); \
-    } \
-    else { \
-      if (current_block->active_extruder) X2_DIR_WRITE(v); else X_DIR_WRITE(v); \
-    }
-  #define X_APPLY_STEP(v,ALWAYS) \
-    if (extruder_duplication_enabled || ALWAYS) { \
-      X_STEP_WRITE(v); \
-      X2_STEP_WRITE(v); \
-    } \
-    else { \
-      if (current_block->active_extruder) X2_STEP_WRITE(v); else X_STEP_WRITE(v); \
-    }
+  #if ENABLED(DUAL_X_CARRIAGE)
+    #define X_APPLY_DIR(v,ALWAYS) \
+      if (extruder_duplication_enabled || ALWAYS) { \
+        X_DIR_WRITE(v); \
+        X2_DIR_WRITE(v); \
+      } \
+      else { \
+        if (current_block->active_extruder) X2_DIR_WRITE(v); else X_DIR_WRITE(v); \
+      }
+    #define X_APPLY_STEP(v,ALWAYS) \
+      if (extruder_duplication_enabled || ALWAYS) { \
+        X_STEP_WRITE(v); \
+        X2_STEP_WRITE(v); \
+      } \
+      else { \
+        if (current_block->active_extruder) X2_STEP_WRITE(v); else X_STEP_WRITE(v); \
+      }
+  #elif ENABLED(X_DUAL_ENDSTOPS)
+    #define X_APPLY_STEP(v,Q) DUAL_ENDSTOP_APPLY_STEP(X,v)
+  #else
+    #define X_APPLY_STEP(v,Q) do{ X_STEP_WRITE(v); X2_STEP_WRITE(v); }while(0)
+  #endif
 #else
   #define X_APPLY_DIR(v,Q) X_DIR_WRITE(v)
   #define X_APPLY_STEP(v,Q) X_STEP_WRITE(v)
@@ -169,7 +202,11 @@ volatile long Stepper::endstops_trigsteps[XYZ];
 
 #if ENABLED(Y_DUAL_STEPPER_DRIVERS)
   #define Y_APPLY_DIR(v,Q) do{ Y_DIR_WRITE(v); Y2_DIR_WRITE((v) != INVERT_Y2_VS_Y_DIR); }while(0)
-  #define Y_APPLY_STEP(v,Q) do{ Y_STEP_WRITE(v); Y2_STEP_WRITE(v); }while(0)
+  #if ENABLED(Y_DUAL_ENDSTOPS)
+    #define Y_APPLY_STEP(v,Q) DUAL_ENDSTOP_APPLY_STEP(Y,v)
+  #else
+    #define Y_APPLY_STEP(v,Q) do{ Y_STEP_WRITE(v); Y2_STEP_WRITE(v); }while(0)
+  #endif
 #else
   #define Y_APPLY_DIR(v,Q) Y_DIR_WRITE(v)
   #define Y_APPLY_STEP(v,Q) Y_STEP_WRITE(v)
@@ -178,21 +215,7 @@ volatile long Stepper::endstops_trigsteps[XYZ];
 #if ENABLED(Z_DUAL_STEPPER_DRIVERS)
   #define Z_APPLY_DIR(v,Q) do{ Z_DIR_WRITE(v); Z2_DIR_WRITE(v); }while(0)
   #if ENABLED(Z_DUAL_ENDSTOPS)
-    #define Z_APPLY_STEP(v,Q) \
-    if (performing_homing) { \
-      if (Z_HOME_DIR < 0) { \
-        if (!(TEST(endstops.old_endstop_bits, Z_MIN) && (count_direction[Z_AXIS] < 0)) && !locked_z_motor) Z_STEP_WRITE(v); \
-        if (!(TEST(endstops.old_endstop_bits, Z2_MIN) && (count_direction[Z_AXIS] < 0)) && !locked_z2_motor) Z2_STEP_WRITE(v); \
-      } \
-      else { \
-        if (!(TEST(endstops.old_endstop_bits, Z_MAX) && (count_direction[Z_AXIS] > 0)) && !locked_z_motor) Z_STEP_WRITE(v); \
-        if (!(TEST(endstops.old_endstop_bits, Z2_MAX) && (count_direction[Z_AXIS] > 0)) && !locked_z2_motor) Z2_STEP_WRITE(v); \
-      } \
-    } \
-    else { \
-      Z_STEP_WRITE(v); \
-      Z2_STEP_WRITE(v); \
-    }
+    #define Z_APPLY_STEP(v,Q) DUAL_ENDSTOP_APPLY_STEP(Z,v)
   #else
     #define Z_APPLY_STEP(v,Q) do{ Z_STEP_WRITE(v); Z2_STEP_WRITE(v); }while(0)
   #endif

Marlin/stepper.h

@@ -87,7 +87,7 @@ class Stepper {
       static bool abort_on_endstop_hit;
     #endif
 
-    #if ENABLED(Z_DUAL_ENDSTOPS)
+    #if ENABLED(X_DUAL_ENDSTOPS) || ENABLED(Y_DUAL_ENDSTOPS) || ENABLED(Z_DUAL_ENDSTOPS)
       static bool performing_homing;
     #endif
 
@@ -103,6 +103,12 @@ class Stepper {
     static uint8_t last_direction_bits;        // The next stepping-bits to be output
     static uint16_t cleaning_buffer_counter;
 
+    #if ENABLED(X_DUAL_ENDSTOPS)
+      static bool locked_x_motor, locked_x2_motor;
+    #endif
+    #if ENABLED(Y_DUAL_ENDSTOPS)
+      static bool locked_y_motor, locked_y2_motor;
+    #endif
     #if ENABLED(Z_DUAL_ENDSTOPS)
       static bool locked_z_motor, locked_z2_motor;
     #endif
@@ -250,8 +256,18 @@ class Stepper {
       static void microstep_readings();
     #endif
 
+    #if ENABLED(X_DUAL_ENDSTOPS)
+      static FORCE_INLINE void set_homing_flag_x(const bool state) { performing_homing = state; }
+      static FORCE_INLINE void set_x_lock(const bool state) { locked_x_motor = state; }
+      static FORCE_INLINE void set_x2_lock(const bool state) { locked_x2_motor = state; }
+    #endif
+    #if ENABLED(Y_DUAL_ENDSTOPS)
+      static FORCE_INLINE void set_homing_flag_y(const bool state) { performing_homing = state; }
+      static FORCE_INLINE void set_y_lock(const bool state) { locked_y_motor = state; }
+      static FORCE_INLINE void set_y2_lock(const bool state) { locked_y2_motor = state; }
+    #endif
     #if ENABLED(Z_DUAL_ENDSTOPS)
-      static FORCE_INLINE void set_homing_flag(const bool state) { performing_homing = state; }
+      static FORCE_INLINE void set_homing_flag_z(const bool state) { performing_homing = state; }
       static FORCE_INLINE void set_z_lock(const bool state) { locked_z_motor = state; }
       static FORCE_INLINE void set_z2_lock(const bool state) { locked_z2_motor = state; }
     #endif

buildroot/bin/opt_add

@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+
+eval "echo \"#define ${1} ${2}\" >>Marlin/Configuration.h"

buildroot/bin/opt_add_adv

@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+
+eval "echo \"#define ${1} ${2}\" >>Marlin/Configuration_adv.h"