Merge pull request #8220 from thinkyhead/bf2_serial_port_-1

[2.0] Add SERIAL_PORT -1 option for configurators

Marlin/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/default/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/AlephObjects/TAZ4/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/AliExpress/CL-260/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/Anet/A6/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/Anet/A8/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/Azteeg/X5GT/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
-#define SERIAL_PORT -1
+#define SERIAL_PORT 0
 
 /**
  * This setting determines the communication speed of the printer.

Marlin/src/config/examples/BQ/Hephestos/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/BQ/Hephestos_2/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/BQ/WITBOX/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/Cartesio/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/Creality/CR-10/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/Felix/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/Felix/DUAL/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/FolgerTech/i3-2020/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/Geeetech/GT2560/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/Geeetech/I3_Pro_X-GT2560/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/Infitary/i3-M508/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/Malyan/M150/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/Micromake/C1/basic/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/Micromake/C1/enhanced/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/Mks/Sbase/Configuration.h

 #ifndef CONFIGURATION_H
 #define CONFIGURATION_H
 #define CONFIGURATION_H_VERSION 020000
-#define USE_AUTOMATIC_VERSIONING
 
 //===========================================================================
 //============================= Getting Started =============================
 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/RepRapWorld/Megatronics/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/RigidBot/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/SCARA/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/Sanguinololu/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/TinyBoy2/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/Velleman/K8200/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/Velleman/K8400/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/Velleman/K8400/Dual-head/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/adafruit/ST7565/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/delta/FLSUN/auto_calibrate/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/delta/FLSUN/kossel_mini/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/delta/generic/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/delta/kossel_mini/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/delta/kossel_pro/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/delta/kossel_xl/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/gCreate/gMax1.5+/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/makibox/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/stm32f103ret6/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/tvrrug/Round2/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/config/examples/wt150/Configuration.h

 // @section machine
 
 /**
- * Select which serial port on the board will be used for communication with the host.
+ * Select the serial port on the board to use for communication with the host.
  * This allows the connection of wireless adapters (for instance) to non-default port pins.
- * Serial port 0 is always used by the Arduino bootloader regardless of this setting.
+ * Note: The first serial port (-1 or 0) will always be used by the Arduino bootloader.
  *
- * :[0, 1, 2, 3, 4, 5, 6, 7]
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT 0
 

Marlin/src/inc/Conditionals_LCD.h

 #define HAS_RESUME_CONTINUE (ENABLED(NEWPANEL) || ENABLED(EMERGENCY_PARSER))
 #define HAS_COLOR_LEDS (ENABLED(BLINKM) || ENABLED(RGB_LED) || ENABLED(RGBW_LED) || ENABLED(PCA9632) || ENABLED(NEOPIXEL_LED))
 
-  // For Re-ARM boards, always use the USB Emulated Serial Port unless RE_ARM_FORCE_SERIAL_PORT is defined
-  #if MB(RAMPS_14_RE_ARM_EFB) || MB(RAMPS_14_RE_ARM_EEB) || MB(RAMPS_14_RE_ARM_EFF) || MB(RAMPS_14_RE_ARM_EEF) || MB(RAMPS_14_RE_ARM_SF)
-    #ifndef RE_ARM_FORCE_SERIAL_PORT
-      #undef SERIAL_PORT
-      #define SERIAL_PORT -1
-    #endif
-  #endif
+// For Re-ARM boards, always use the USB Emulated Serial Port unless RE_ARM_FORCE_SERIAL_PORT is defined
+#if !defined(RE_ARM_FORCE_SERIAL_PORT) && (MB(RAMPS_14_RE_ARM_EFB) || MB(RAMPS_14_RE_ARM_EEB) || MB(RAMPS_14_RE_ARM_EFF) || MB(RAMPS_14_RE_ARM_EEF) || MB(RAMPS_14_RE_ARM_SF))
+  #undef SERIAL_PORT
+  #define SERIAL_PORT -1
+#endif
 
 #endif // CONDITIONALS_LCD_H