MMU2 as standard serial device (#20771)

Marlin/src/HAL/AVR/HAL.h

@@ -97,6 +97,13 @@ typedef int8_t pin_t;
   #endif
 #endif
 
+#ifdef MMU2_SERIAL_PORT
+  #if !WITHIN(MMU2_SERIAL_PORT, -1, 3)
+    #error "MMU2_SERIAL_PORT must be from -1 to 3. Please update your configuration."
+  #endif
+  #define MMU2_SERIAL mmuSerial
+#endif
+
 #ifdef LCD_SERIAL_PORT
   #if !WITHIN(LCD_SERIAL_PORT, -1, 3)
     #error "LCD_SERIAL_PORT must be from -1 to 3. Please update your configuration."

Marlin/src/HAL/DUE/HAL.h

@@ -59,6 +59,14 @@
   #endif
 #endif
 
+#ifdef MMU2_SERIAL_PORT
+  #if WITHIN(MMU2_SERIAL_PORT, 0, 3)
+    #define MMU2_SERIAL MSERIAL(SERIAL_PORT)
+  #else
+    #error "MMU2_SERIAL_PORT must be from 0 to 3. Please update your configuration."
+  #endif
+#endif
+
 #ifdef LCD_SERIAL_PORT
   #if LCD_SERIAL_PORT == -1
     #define LCD_SERIAL lcdSerial

Marlin/src/HAL/LPC1768/HAL.h

@@ -82,6 +82,16 @@ extern "C" volatile uint32_t _millis;
   #endif
 #endif
 
+#ifdef MMU2_SERIAL_PORT
+  #if MMU2_SERIAL_PORT == -1
+    #define MMU2_SERIAL UsbSerial
+  #elif WITHIN(MMU2_SERIAL_PORT, 0, 3)
+    #define MMU2_SERIAL MSERIAL(MMU2_SERIAL_PORT)
+  #else
+    #error "MMU2_SERIAL_PORT must be from -1 to 3. Please update your configuration."
+  #endif
+#endif
+
 #ifdef LCD_SERIAL_PORT
   #if LCD_SERIAL_PORT == -1
     #define LCD_SERIAL UsbSerial

Marlin/src/HAL/SAMD51/HAL.h

@@ -57,6 +57,16 @@
     #endif
   #endif
 
+  #ifdef MMU2_SERIAL_PORT
+    #if MMU2_SERIAL_PORT == -1
+      #define MMU2_SERIAL Serial
+    #elif WITHIN(MMU2_SERIAL_PORT, 0, 3)
+      #define MMU2_SERIAL MSERIAL(MMU2_SERIAL_PORT)
+    #else
+      #error "MMU2_SERIAL_PORT must be from -1 to 3. Please update your configuration."
+    #endif
+  #endif
+
   #ifdef LCD_SERIAL_PORT
     #if LCD_SERIAL_PORT == -1
       #define LCD_SERIAL Serial

Marlin/src/HAL/SAMD51/MarlinSerial_AGCM4.cpp

@@ -21,13 +21,13 @@
 #ifdef ADAFRUIT_GRAND_CENTRAL_M4
 
 /**
- * Framework doesn't define some serial to save sercom resources
+ * Framework doesn't define some serials to save sercom resources
  * hence if these are used I need to define them
  */
 
 #include "../../inc/MarlinConfig.h"
 
-#if SERIAL_PORT == 1 || SERIAL_PORT_2 == 1
+#if USING_SERIAL_1
   Uart Serial2(&sercom4, PIN_SERIAL2_RX, PIN_SERIAL2_TX, PAD_SERIAL2_RX, PAD_SERIAL2_TX);
   void SERCOM4_0_Handler() { Serial2.IrqHandler(); }
   void SERCOM4_1_Handler() { Serial2.IrqHandler(); }
@@ -35,7 +35,7 @@
   void SERCOM4_3_Handler() { Serial2.IrqHandler(); }
 #endif
 
-#if SERIAL_PORT == 2 || SERIAL_PORT_2 == 2
+#if USING_SERIAL_2
   Uart Serial3(&sercom1, PIN_SERIAL3_RX, PIN_SERIAL3_TX, PAD_SERIAL3_RX, PAD_SERIAL3_TX);
   void SERCOM1_0_Handler() { Serial3.IrqHandler(); }
   void SERCOM1_1_Handler() { Serial3.IrqHandler(); }
@@ -43,7 +43,7 @@
   void SERCOM1_3_Handler() { Serial3.IrqHandler(); }
 #endif
 
-#if SERIAL_PORT == 3 || SERIAL_PORT_2 == 3
+#if USING_SERIAL_3
   Uart Serial4(&sercom5, PIN_SERIAL4_RX, PIN_SERIAL4_TX, PAD_SERIAL4_RX, PAD_SERIAL4_TX);
   void SERCOM5_0_Handler() { Serial4.IrqHandler(); }
   void SERCOM5_1_Handler() { Serial4.IrqHandler(); }

Marlin/src/HAL/STM32/HAL.h

@@ -65,6 +65,16 @@
   #endif
 #endif
 
+#ifdef MMU2_SERIAL_PORT
+  #if MMU2_SERIAL_PORT == -1
+    #define MMU2_SERIAL SerialUSB
+  #elif WITHIN(MMU2_SERIAL_PORT, 1, 6)
+    #define MMU2_SERIAL MSERIAL(MMU2_SERIAL_PORT)
+  #else
+    #error "MMU2_SERIAL_PORT must be -1 or from 1 to 6. Please update your configuration."
+  #endif
+#endif
+
 #ifdef LCD_SERIAL_PORT
   #if LCD_SERIAL_PORT == -1
     #define LCD_SERIAL SerialUSB

Marlin/src/HAL/STM32/MarlinSerial.cpp

@@ -48,6 +48,10 @@
   DECLARE_SERIAL_PORT_EXP(SERIAL_PORT_2)
 #endif
 
+#if defined(MMU2_SERIAL_PORT) && MMU2_SERIAL_PORT >= 0
+  DECLARE_SERIAL_PORT_EXP(MMU2_SERIAL_PORT)
+#endif
+
 #if defined(LCD_SERIAL_PORT) && LCD_SERIAL_PORT >= 0
   DECLARE_SERIAL_PORT_EXP(LCD_SERIAL_PORT)
 #endif

Marlin/src/HAL/STM32F1/HAL.h

@@ -99,6 +99,18 @@
   #endif
 #endif
 
+#ifdef MMU2_SERIAL_PORT
+  #if MMU2_SERIAL_PORT == -1
+    #define MMU2_SERIAL UsbSerial
+  #elif WITHIN(MMU2_SERIAL_PORT, 1, NUM_UARTS)
+    #define MMU2_SERIAL MSERIAL(MMU2_SERIAL_PORT)
+  #elif NUM_UARTS == 5
+    #error "MMU2_SERIAL_PORT must be -1 or from 1 to 5. Please update your configuration."
+  #else
+    #error "MMU2_SERIAL_PORT must be -1 or from 1 to 3. Please update your configuration."
+  #endif
+#endif
+
 #ifdef LCD_SERIAL_PORT
   #if LCD_SERIAL_PORT == -1
     #define LCD_SERIAL UsbSerial