Split up pins to make it more manageable

Hopefully this is helpful to organization and future expansion….

Marlin/pins_AZTEEG_X3_PRO.h

@@ -0,0 +1,30 @@
+/**
+ * AZTEEG_X3_PRO (Arduino Mega) pin assignments
+ */
+
+#include "pins_RAMPS_13.h"
+
+#define E2_STEP_PIN        23
+#define E2_DIR_PIN         25
+#define E2_ENABLE_PIN      40
+
+#define E3_STEP_PIN        27
+#define E3_DIR_PIN         29
+#define E3_ENABLE_PIN      41
+
+#define E4_STEP_PIN        43
+#define E4_DIR_PIN         37
+#define E4_ENABLE_PIN      42
+
+#define HEATER_2_PIN       16
+#define HEATER_3_PIN       17
+#define HEATER_4_PIN       4
+#define HEATER_5_PIN       5
+#define HEATER_6_PIN       6
+#define HEATER_7_PIN       11
+
+#define TEMP_2_PIN         12   // ANALOG NUMBERING
+#define TEMP_3_PIN         11   // ANALOG NUMBERING
+#define TEMP_4_PIN         10   // ANALOG NUMBERING
+#define TC1                4    // ANALOG NUMBERING Thermo couple on Azteeg X3Pro
+#define TC2                5    // ANALOG NUMBERING Thermo couple on Azteeg X3Pro