Initial Commit

Merge branch 'bugfix-2.0.x' of https://github.com/MarlinFirmware/Marlin into bugfix-2.0.x
🎨 Apply shorthand and cleanups
2021-05-25 09:21:30 -04:00 · 2021-05-23 15:06:33 -04:00 · 2021-05-23 03:04:36 -05:00 · 2021-05-23 03:04:36 -05:00 · 2021-05-23 03:04:31 -05:00 · 2021-05-23 01:15:23 +00:00
1416 changed files with 50456 additions and 24559 deletions
@@ -4,10 +4,10 @@ root = true
 [{*.patch,syntax_test_*}]
 trim_trailing_whitespace = false

-[{*.c,*.cpp,*.h}]
+[{*.c,*.cpp,*.h,*.ino}]
 charset = utf-8

-[{*.c,*.cpp,*.h,Makefile}]
+[{*.c,*.cpp,*.h,*.ino,Makefile}]
 trim_trailing_whitespace = true
 insert_final_newline = true
 end_of_line = lf
@@ -72,6 +72,7 @@ jobs:

        # STM32 (ST) Environments

+        - STM32F103RC_btt_stm32
        - STM32F407VE_black
        - STM32F401VE_STEVAL
        - BIGTREE_BTT002
@@ -86,9 +87,12 @@ jobs:
        - FLYF407ZG
        - rumba32
        - LERDGEX
+        - LERDGEK
        - mks_robin_nano35_stm32
        - NUCLEO_F767ZI
        - REMRAM_V1
+        - BTT_SKR_SE_BX
+        - chitu_f103

        # Put lengthy tests last

@@ -98,6 +102,7 @@ jobs:
        # Non-working environment tests
        #- at90usb1286_cdc
        #- STM32F103CB_malyan
+        #- STM32F103RE
        #- mks_robin_mini

    steps:
@@ -122,29 +122,6 @@ tags
 .gcc-flags.json
 /lib/

-# Workaround for Deviot+platformio quirks
-Marlin/lib
-Marlin/platformio.ini
-Marlin/*/platformio.ini
-Marlin/*/*/platformio.ini
-Marlin/*/*/*/platformio.ini
-Marlin/*/*/*/*/platformio.ini
-Marlin/.travis.yml
-Marlin/*/.travis.yml
-Marlin/*/*/.travis.yml
-Marlin/*/*/*/.travis.yml
-Marlin/*/*/*/*/.travis.yml
-Marlin/.gitignore
-Marlin/*/.gitignore
-Marlin/*/*/.gitignore
-Marlin/*/*/*/.gitignore
-Marlin/*/*/*/*/.gitignore
-Marlin/readme.txt
-Marlin/*/readme.txt
-Marlin/*/*/readme.txt
-Marlin/*/*/*/readme.txt
-Marlin/*/*/*/*/readme.txt
-
 # Secure Credentials
 Configuration_Secure.h

@@ -35,42 +35,41 @@
 *
 * Advanced settings can be found in Configuration_adv.h
 */
-#define CONFIGURATION_H_VERSION 020008
+#define CONFIGURATION_H_VERSION 02000801

 //===========================================================================
 //============================= Getting Started =============================
 //===========================================================================

 /**
- * Here are some standard links for getting your machine calibrated:
+ * Here are some useful links to help get your machine configured and calibrated:
 *
- * https://reprap.org/wiki/Calibration
- * https://youtu.be/wAL9d7FgInk
- * http://calculator.josefprusa.cz
- * https://reprap.org/wiki/Triffid_Hunter%27s_Calibration_Guide
- * https://www.thingiverse.com/thing:5573
- * https://sites.google.com/site/repraplogphase/calibration-of-your-reprap
- * https://www.thingiverse.com/thing:298812
+ * Example Configs:     https://github.com/MarlinFirmware/Configurations/branches/all
+ *
+ * Průša Calculator:    https://blog.prusaprinters.org/calculator_3416/
+ *
+ * Calibration Guides:  https://reprap.org/wiki/Calibration
+ *                      https://reprap.org/wiki/Triffid_Hunter%27s_Calibration_Guide
+ *                      https://sites.google.com/site/repraplogphase/calibration-of-your-reprap
+ *                      https://youtu.be/wAL9d7FgInk
+ *
+ * Calibration Objects: https://www.thingiverse.com/thing:5573
+ *                      https://www.thingiverse.com/thing:1278865
 */

 //===========================================================================
-//============================= DELTA Printer ===============================
+//========================== DELTA / SCARA / TPARA ==========================
 //===========================================================================
-// For a Delta printer, start with one of the configuration files in the config/examples/delta directory
-// from https://github.com/MarlinFirmware/Configurations/branches/all and customize for your machine.
 //
-
-//===========================================================================
-//============================= SCARA Printer ===============================
-//===========================================================================
-// For a SCARA printer, start with one of the configuration files in the config/examples/SCARA directory
-// from https://github.com/MarlinFirmware/Configurations/branches/all and customize for your machine.
+// Download configurations from the link above and customize for your machine.
+// Examples are located in config/examples/delta, .../SCARA, and .../TPARA.
 //
+//===========================================================================

 // @section info

 // Author info of this build printed to the host during boot and M115
-#define STRING_CONFIG_H_AUTHOR "(none, default config)" // Who made the changes.
+#define STRING_CONFIG_H_AUTHOR "Insanity Automation" // Who made the changes.
 //#define CUSTOM_VERSION_FILE Version.h // Path from the root directory (no quotes)

 /**
@@ -106,14 +105,9 @@
 #define SERIAL_PORT 0

 /**
- * Select a secondary serial port on the board to use for communication with the host.
- * Currently Ethernet (-2) is only supported on Teensy 4.1 boards.
- * :[-2, -1, 0, 1, 2, 3, 4, 5, 6, 7]
- */
-//#define SERIAL_PORT_2 -1
-
-/**
- * This setting determines the communication speed of the printer.
+ * Serial Port Baud Rate
+ * This is the default communication speed for all serial ports.
+ * Set the baud rate defaults for additional serial ports below.
 *
 * 250000 works in most cases, but you might try a lower speed if
 * you commonly experience drop-outs during host printing.
@@ -122,13 +116,30 @@
 * :[2400, 9600, 19200, 38400, 57600, 115200, 250000, 500000, 1000000]
 */
 #define BAUDRATE 250000
+//#define BAUD_RATE_GCODE     // Enable G-code M575 to set the baud rate
+
+/**
+ * Select a secondary serial port on the board to use for communication with the host.
+ * Currently Ethernet (-2) is only supported on Teensy 4.1 boards.
+ * :[-2, -1, 0, 1, 2, 3, 4, 5, 6, 7]
+ */
+//#define SERIAL_PORT_2 -1
+//#define BAUDRATE_2 250000   // Enable to override BAUDRATE
+
+/**
+ * Select a third serial port on the board to use for communication with the host.
+ * Currently only supported for AVR, DUE, LPC1768/9 and STM32/STM32F1
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
+ */
+//#define SERIAL_PORT_3 1
+//#define BAUDRATE_3 250000   // Enable to override BAUDRATE

 // Enable the Bluetooth serial interface on AT90USB devices
 //#define BLUETOOTH

 // Choose the name from boards.h that matches your setup
 #ifndef MOTHERBOARD
-  #define MOTHERBOARD BOARD_RAMPS_14_EFB
+  #define MOTHERBOARD BOARD_ORTUR_4
 #endif

 // Name displayed in the LCD "Ready" message and Info menu
@@ -161,11 +172,11 @@
 * Multi-Material Unit
 * Set to one of these predefined models:
 *
- *   PRUSA_MMU1      : Průša MMU1 (The "multiplexer" version)
- *   PRUSA_MMU2      : Průša MMU2
- *   PRUSA_MMU2S     : Průša MMU2S (Requires MK3S extruder with motion sensor, EXTRUDERS = 5)
- *   SMUFF_EMU_MMU2  : Technik Gegg SMUFF (Průša MMU2 emulation mode)
- *   SMUFF_EMU_MMU2S : Technik Gegg SMUFF (Průša MMU2S emulation mode)
+ *   PRUSA_MMU1           : Průša MMU1 (The "multiplexer" version)
+ *   PRUSA_MMU2           : Průša MMU2
+ *   PRUSA_MMU2S          : Průša MMU2S (Requires MK3S extruder with motion sensor, EXTRUDERS = 5)
+ *   EXTENDABLE_EMU_MMU2  : MMU with configurable number of filaments (ERCF, SMuFF or similar with Průša MMU2 compatible firmware)
+ *   EXTENDABLE_EMU_MMU2S : MMUS with configurable number of filaments (ERCF, SMuFF or similar with Průša MMU2 compatible firmware)
 *
 * Requires NOZZLE_PARK_FEATURE to park print head in case MMU unit fails.
 * See additional options in Configuration_adv.h.
@@ -330,8 +341,10 @@
    #define AUTO_POWER_E_FANS
    #define AUTO_POWER_CONTROLLERFAN
    #define AUTO_POWER_CHAMBER_FAN
+    #define AUTO_POWER_COOLER_FAN
    //#define AUTO_POWER_E_TEMP        50 // (°C) Turn on PSU if any extruder is over this temperature
    //#define AUTO_POWER_CHAMBER_TEMP  30 // (°C) Turn on PSU if the chamber is over this temperature
+    //#define AUTO_POWER_COOLER_TEMP   26 // (°C) Turn on PSU if the cooler is over this temperature
    #define POWER_TIMEOUT              30 // (s) Turn off power if the machine is idle for this duration
    //#define POWER_OFF_DELAY          60 // (s) Delay of poweroff after M81 command. Useful to let fans run for extra time.
  #endif
@@ -416,9 +429,10 @@
 #define TEMP_SENSOR_5 0
 #define TEMP_SENSOR_6 0
 #define TEMP_SENSOR_7 0
-#define TEMP_SENSOR_BED 0
+#define TEMP_SENSOR_BED 1
 #define TEMP_SENSOR_PROBE 0
 #define TEMP_SENSOR_CHAMBER 0
+#define TEMP_SENSOR_COOLER 0

 // Dummy thermistor constant temperature readings, for use with 998 and 999
 #define DUMMY_THERMISTOR_998_VALUE  25
@@ -435,13 +449,17 @@
 //#define TEMP_SENSOR_1_AS_REDUNDANT
 #define MAX_REDUNDANT_TEMP_SENSOR_DIFF 10

-#define TEMP_RESIDENCY_TIME     10  // (seconds) Time to wait for hotend to "settle" in M109
-#define TEMP_WINDOW              1  // (°C) Temperature proximity for the "temperature reached" timer
-#define TEMP_HYSTERESIS          3  // (°C) Temperature proximity considered "close enough" to the target
+#define TEMP_RESIDENCY_TIME         5  // (seconds) Time to wait for hotend to "settle" in M109
+#define TEMP_WINDOW                  2  // (°C) Temperature proximity for the "temperature reached" timer
+#define TEMP_HYSTERESIS              3  // (°C) Temperature proximity considered "close enough" to the target

-#define TEMP_BED_RESIDENCY_TIME 10  // (seconds) Time to wait for bed to "settle" in M190
-#define TEMP_BED_WINDOW          1  // (°C) Temperature proximity for the "temperature reached" timer
-#define TEMP_BED_HYSTERESIS      3  // (°C) Temperature proximity considered "close enough" to the target
+#define TEMP_BED_RESIDENCY_TIME     5  // (seconds) Time to wait for bed to "settle" in M190
+#define TEMP_BED_WINDOW              1  // (°C) Temperature proximity for the "temperature reached" timer
+#define TEMP_BED_HYSTERESIS          3  // (°C) Temperature proximity considered "close enough" to the target
+
+#define TEMP_CHAMBER_RESIDENCY_TIME 10  // (seconds) Time to wait for chamber to "settle" in M191
+#define TEMP_CHAMBER_WINDOW          1  // (°C) Temperature proximity for the "temperature reached" timer
+#define TEMP_CHAMBER_HYSTERESIS      3  // (°C) Temperature proximity considered "close enough" to the target

 // Below this temperature the heater will be switched off
 // because it probably indicates a broken thermistor wire.
@@ -454,6 +472,7 @@
 #define HEATER_6_MINTEMP   5
 #define HEATER_7_MINTEMP   5
 #define BED_MINTEMP        5
+#define CHAMBER_MINTEMP    5

 // Above this temperature the heater will be switched off.
 // This can protect components from overheating, but NOT from shorts and failures.
@@ -466,7 +485,18 @@
 #define HEATER_5_MAXTEMP 275
 #define HEATER_6_MAXTEMP 275
 #define HEATER_7_MAXTEMP 275
-#define BED_MAXTEMP      150
+#define BED_MAXTEMP      120
+#define CHAMBER_MAXTEMP  60
+
+/**
+ * Thermal Overshoot
+ * During heatup (and printing) the temperature can often "overshoot" the target by many degrees
+ * (especially before PID tuning). Setting the target temperature too close to MAXTEMP guarantees
+ * a MAXTEMP shutdown! Use these values to forbid temperatures being set too close to MAXTEMP.
+ */
+#define HOTEND_OVERSHOOT 15   // (°C) Forbid temperatures over MAXTEMP - OVERSHOOT
+#define BED_OVERSHOOT    10   // (°C) Forbid temperatures over MAXTEMP - OVERSHOOT
+#define COOLER_OVERSHOOT  2   // (°C) Forbid temperatures closer than OVERSHOOT

 //===========================================================================
 //============================= PID Settings ================================
@@ -480,8 +510,8 @@
 #define PID_K1 0.95      // Smoothing factor within any PID loop

 #if ENABLED(PIDTEMP)
-  //#define PID_EDIT_MENU         // Add PID editing to the "Advanced Settings" menu. (~700 bytes of PROGMEM)
-  //#define PID_AUTOTUNE_MENU     // Add PID auto-tuning to the "Advanced Settings" menu. (~250 bytes of PROGMEM)
+  #define PID_EDIT_MENU         // Add PID editing to the "Advanced Settings" menu. (~700 bytes of PROGMEM)
+  #define PID_AUTOTUNE_MENU     // Add PID auto-tuning to the "Advanced Settings" menu. (~250 bytes of PROGMEM)
  //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                  // Set/get with gcode: M301 E[extruder number, 0-2]

@@ -515,7 +545,7 @@
 * heater. If your configuration is significantly different than this and you don't understand
 * the issues involved, don't use bed PID until someone else verifies that your hardware works.
 */
-//#define PIDTEMPBED
+#define PIDTEMPBED

 //#define BED_LIMIT_SWITCHING

@@ -533,14 +563,58 @@

  // 120V 250W silicone heater into 4mm borosilicate (MendelMax 1.5+)
  // from FOPDT model - kp=.39 Tp=405 Tdead=66, Tc set to 79.2, aggressive factor of .15 (vs .1, 1, 10)
-  #define DEFAULT_bedKp 10.00
-  #define DEFAULT_bedKi .023
-  #define DEFAULT_bedKd 305.4
+  #define DEFAULT_bedKp 87.23
+  #define DEFAULT_bedKi 13.31
+  #define DEFAULT_bedKd 381.14

  // FIND YOUR OWN: "M303 E-1 C8 S90" to run autotune on the bed at 90 degreesC for 8 cycles.
 #endif // PIDTEMPBED

-#if EITHER(PIDTEMP, PIDTEMPBED)
+//===========================================================================
+//==================== PID > Chamber Temperature Control ====================
+//===========================================================================
+
+/**
+ * PID Chamber Heating
+ *
+ * If this option is enabled set PID constants below.
+ * If this option is disabled, bang-bang will be used and CHAMBER_LIMIT_SWITCHING will enable
+ * hysteresis.
+ *
+ * The PID frequency will be the same as the extruder PWM.
+ * If PID_dT is the default, and correct for the hardware/configuration, that means 7.689Hz,
+ * which is fine for driving a square wave into a resistive load and does not significantly
+ * impact FET heating. This also works fine on a Fotek SSR-10DA Solid State Relay into a 200W
+ * heater. If your configuration is significantly different than this and you don't understand
+ * the issues involved, don't use chamber PID until someone else verifies that your hardware works.
+ */
+//#define PIDTEMPCHAMBER
+//#define CHAMBER_LIMIT_SWITCHING
+
+/**
+ * Max Chamber Power
+ * Applies to all forms of chamber control (PID, bang-bang, and bang-bang with hysteresis).
+ * When set to any value below 255, enables a form of PWM to the chamber heater that acts like a divider
+ * so don't use it unless you are OK with PWM on your heater. (See the comment on enabling PIDTEMPCHAMBER)
+ */
+#define MAX_CHAMBER_POWER 255 // limits duty cycle to chamber heater; 255=full current
+
+#if ENABLED(PIDTEMPCHAMBER)
+  #define MIN_CHAMBER_POWER 0
+  //#define PID_CHAMBER_DEBUG // Sends debug data to the serial port.
+
+  // Lasko "MyHeat Personal Heater" (200w) modified with a Fotek SSR-10DA to control only the heating element
+  // and placed inside the small Creality printer enclosure tent.
+  //
+  #define DEFAULT_chamberKp 37.04
+  #define DEFAULT_chamberKi 1.40
+  #define DEFAULT_chamberKd 655.17
+  // M309 P37.04 I1.04 D655.17
+
+  // FIND YOUR OWN: "M303 E-2 C8 S50" to run autotune on the chamber at 50 degreesC for 8 cycles.
+#endif // PIDTEMPCHAMBER
+
+#if ANY(PIDTEMP, PIDTEMPBED, PIDTEMPCHAMBER)
  //#define PID_DEBUG             // Sends debug data to the serial port. Use 'M303 D' to toggle activation.
  //#define PID_OPENLOOP          // Puts PID in open loop. M104/M140 sets the output power from 0 to PID_MAX
  //#define SLOW_PWM_HEATERS      // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
@@ -587,6 +661,7 @@
 #define THERMAL_PROTECTION_HOTENDS // Enable thermal protection for all extruders
 #define THERMAL_PROTECTION_BED     // Enable thermal protection for the heated bed
 #define THERMAL_PROTECTION_CHAMBER // Enable thermal protection for the heated chamber
+#define THERMAL_PROTECTION_COOLER  // Enable thermal protection for the laser cooling

 //===========================================================================
 //============================= Mechanical Settings =========================
@@ -647,13 +722,13 @@
 #endif

 // Mechanical endstop with COM to ground and NC to Signal uses "false" here (most common setup).
-#define X_MIN_ENDSTOP_INVERTING false // Set to true to invert the logic of the endstop.
-#define Y_MIN_ENDSTOP_INVERTING false // Set to true to invert the logic of the endstop.
-#define Z_MIN_ENDSTOP_INVERTING false // Set to true to invert the logic of the endstop.
+#define X_MIN_ENDSTOP_INVERTING true // Set to true to invert the logic of the endstop.
+#define Y_MIN_ENDSTOP_INVERTING true // Set to true to invert the logic of the endstop.
+#define Z_MIN_ENDSTOP_INVERTING true // Set to true to invert the logic of the endstop.
 #define X_MAX_ENDSTOP_INVERTING false // Set to true to invert the logic of the endstop.
 #define Y_MAX_ENDSTOP_INVERTING false // Set to true to invert the logic of the endstop.
 #define Z_MAX_ENDSTOP_INVERTING false // Set to true to invert the logic of the endstop.
-#define Z_MIN_PROBE_ENDSTOP_INVERTING false // Set to true to invert the logic of the probe.
+#define Z_MIN_PROBE_ENDSTOP_INVERTING true // Set to true to invert the logic of the probe.

 /**
 * Stepper Drivers
@@ -736,14 +811,14 @@
 * Override with M92
 *                                      X, Y, Z, E0 [, E1[, E2...]]
 */
-#define DEFAULT_AXIS_STEPS_PER_UNIT   { 80, 80, 400, 500 }
+#define DEFAULT_AXIS_STEPS_PER_UNIT   { 80, 80, 400, 95 }

 /**
 * Default Max Feed Rate (mm/s)
 * Override with M203
 *                                      X, Y, Z, E0 [, E1[, E2...]]
 */
-#define DEFAULT_MAX_FEEDRATE          { 300, 300, 5, 25 }
+#define DEFAULT_MAX_FEEDRATE          { 500, 500, 10, 65 }

 //#define LIMITED_MAX_FR_EDITING        // Limit edit via M203 or LCD to DEFAULT_MAX_FEEDRATE * 2
 #if ENABLED(LIMITED_MAX_FR_EDITING)
@@ -756,7 +831,7 @@
 * Override with M201
 *                                      X, Y, Z, E0 [, E1[, E2...]]
 */
-#define DEFAULT_MAX_ACCELERATION      { 3000, 3000, 100, 10000 }
+#define DEFAULT_MAX_ACCELERATION      { 2500, 2500, 18000, 8000 }

 //#define LIMITED_MAX_ACCEL_EDITING     // Limit edit via M201 or LCD to DEFAULT_MAX_ACCELERATION * 2
 #if ENABLED(LIMITED_MAX_ACCEL_EDITING)
@@ -771,8 +846,8 @@
 *   M204 R    Retract Acceleration
 *   M204 T    Travel Acceleration
 */
-#define DEFAULT_ACCELERATION          3000    // X, Y, Z and E acceleration for printing moves
-#define DEFAULT_RETRACT_ACCELERATION  3000    // E acceleration for retracts
+#define DEFAULT_ACCELERATION          2000    // X, Y, Z and E acceleration for printing moves
+#define DEFAULT_RETRACT_ACCELERATION  2000    // E acceleration for retracts
 #define DEFAULT_TRAVEL_ACCELERATION   3000    // X, Y, Z acceleration for travel (non printing) moves

 /**
@@ -783,10 +858,10 @@
 * When changing speed and direction, if the difference is less than the
 * value set here, it may happen instantaneously.
 */
-//#define CLASSIC_JERK
+#define CLASSIC_JERK
 #if ENABLED(CLASSIC_JERK)
-  #define DEFAULT_XJERK 10.0
-  #define DEFAULT_YJERK 10.0
+  #define DEFAULT_XJERK 15.0
+  #define DEFAULT_YJERK 15.0
  #define DEFAULT_ZJERK  0.3

  //#define TRAVEL_EXTRA_XYJERK 0.0     // Additional jerk allowance for all travel moves
@@ -820,7 +895,7 @@
 *
 * See https://github.com/synthetos/TinyG/wiki/Jerk-Controlled-Motion-Explained
 */
-//#define S_CURVE_ACCELERATION
+#define S_CURVE_ACCELERATION

 //===========================================================================
 //============================= Z Probe Options =============================
@@ -836,7 +911,7 @@
 * The probe replaces the Z-MIN endstop and is used for Z homing.
 * (Automatically enables USE_PROBE_FOR_Z_HOMING.)
 */
-#define Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN
+//#define Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN

 // Force the use of the probe for Z-axis homing
 //#define USE_PROBE_FOR_Z_HOMING
@@ -871,13 +946,12 @@
 * or (with LCD_BED_LEVELING) the LCD controller.
 */
 //#define PROBE_MANUALLY
-//#define MANUAL_PROBE_START_Z 0.2

 /**
 * A Fix-Mounted Probe either doesn't deploy or needs manual deployment.
 *   (e.g., an inductive probe or a nozzle-based probe-switch.)
 */
-//#define FIX_MOUNTED_PROBE
+#define FIX_MOUNTED_PROBE

 /**
 * Use the nozzle as the probe, as with a conductive
@@ -986,20 +1060,20 @@
 *     |    [-]    |
 *     O-- FRONT --+
 */
-#define NOZZLE_TO_PROBE_OFFSET { 10, 10, 0 }
+#define NOZZLE_TO_PROBE_OFFSET { -25, 0, 0 }

 // Most probes should stay away from the edges of the bed, but
 // with NOZZLE_AS_PROBE this can be negative for a wider probing area.
-#define PROBING_MARGIN 10
+#define PROBING_MARGIN 8

 // X and Y axis travel speed (mm/min) between probes
-#define XY_PROBE_SPEED (133*60)
+#define XY_PROBE_FEEDRATE (133*60)

 // Feedrate (mm/min) for the first approach when double-probing (MULTIPLE_PROBING == 2)
-#define Z_PROBE_SPEED_FAST (4*60)
+#define Z_PROBE_FEEDRATE_FAST (10*60)

 // Feedrate (mm/min) for the "accurate" probe of each point
-#define Z_PROBE_SPEED_SLOW (Z_PROBE_SPEED_FAST / 2)
+#define Z_PROBE_FEEDRATE_SLOW (Z_PROBE_FEEDRATE_FAST / 2)

 /**
 * Probe Activation Switch
@@ -1037,7 +1111,7 @@
 * A total of 2 does fast/slow probes with a weighted average.
 * A total of 3 or more adds more slow probes, taking the average.
 */
-//#define MULTIPLE_PROBING 2
+#define MULTIPLE_PROBING 2
 //#define EXTRA_PROBING    1

 /**
@@ -1054,16 +1128,16 @@
 * Example: `M851 Z-5` with a CLEARANCE of 4  =>  9mm from bed to nozzle.
 *     But: `M851 Z+1` with a CLEARANCE of 2  =>  2mm from bed to nozzle.
 */
-#define Z_CLEARANCE_DEPLOY_PROBE   10 // Z Clearance for Deploy/Stow
+#define Z_CLEARANCE_DEPLOY_PROBE   5 // Z Clearance for Deploy/Stow
 #define Z_CLEARANCE_BETWEEN_PROBES  5 // Z Clearance between probe points
 #define Z_CLEARANCE_MULTI_PROBE     5 // Z Clearance between multiple probes
 //#define Z_AFTER_PROBING           5 // Z position after probing is done

-#define Z_PROBE_LOW_POINT          -2 // Farthest distance below the trigger-point to go before stopping
+#define Z_PROBE_LOW_POINT          -4 // Farthest distance below the trigger-point to go before stopping

 // For M851 give a range for adjusting the Z probe offset
-#define Z_PROBE_OFFSET_RANGE_MIN -20
-#define Z_PROBE_OFFSET_RANGE_MAX 20
+#define Z_PROBE_OFFSET_RANGE_MIN -9
+#define Z_PROBE_OFFSET_RANGE_MAX 9

 // Enable the M48 repeatability test to test probe accuracy
 //#define Z_MIN_PROBE_REPEATABILITY_TEST
@@ -1084,6 +1158,7 @@
 //#define PROBING_HEATERS_OFF       // Turn heaters off when probing
 #if ENABLED(PROBING_HEATERS_OFF)
  //#define WAIT_FOR_BED_HEATER     // Wait for bed to heat back up between probes (to improve accuracy)
+  //#define WAIT_FOR_HOTEND         // Wait for hotend to heat back up between probes (to improve accuracy & prevent cold extrude)
 #endif
 //#define PROBING_FANS_OFF          // Turn fans off when probing
 //#define PROBING_STEPPERS_OFF      // Turn steppers off (unless needed to hold position) when probing
@@ -1122,12 +1197,12 @@
 // Invert the stepper direction. Change (or reverse the motor connector) if an axis goes the wrong way.
 #define INVERT_X_DIR false
 #define INVERT_Y_DIR true
-#define INVERT_Z_DIR false
+#define INVERT_Z_DIR true

 // @section extruder

 // For direct drive extruder v9 set to true, for geared extruder set to false.
-#define INVERT_E0_DIR false
+#define INVERT_E0_DIR true
 #define INVERT_E1_DIR false
 #define INVERT_E2_DIR false
 #define INVERT_E3_DIR false
@@ -1140,7 +1215,13 @@

 //#define NO_MOTION_BEFORE_HOMING // Inhibit movement until all axes have been homed. Also enable HOME_AFTER_DEACTIVATE for extra safety.
 //#define HOME_AFTER_DEACTIVATE   // Require rehoming after steppers are deactivated. Also enable NO_MOTION_BEFORE_HOMING for extra safety.
-//#define UNKNOWN_Z_NO_RAISE      // Don't raise Z (lower the bed) if Z is "unknown." For beds that fall when Z is powered off.
+
+/**
+ * Set Z_IDLE_HEIGHT if the Z-Axis moves on its own when steppers are disabled.
+ *  - Use a low value (i.e., Z_MIN_POS) if the nozzle falls down to the bed.
+ *  - Use a large value (i.e., Z_MAX_POS) if the bed falls down, away from the nozzle.
+ */
+//#define Z_IDLE_HEIGHT Z_HOME_POS

 //#define Z_HOMING_HEIGHT  4      // (mm) Minimal Z height before homing (G28) for Z clearance above the bed, clamps, ...
                                  // Be sure to have this much clearance over your Z_MAX_POS to prevent grinding.
@@ -1155,17 +1236,17 @@

 // @section machine

-// The size of the print bed
-#define X_BED_SIZE 200
-#define Y_BED_SIZE 200
+// The size of the printable area
+#define X_BED_SIZE 255
+#define Y_BED_SIZE 300

 // Travel limits (mm) after homing, corresponding to endstop positions.
-#define X_MIN_POS 0
-#define Y_MIN_POS 0
+#define X_MIN_POS -10.5
+#define Y_MIN_POS -9
 #define Z_MIN_POS 0
-#define X_MAX_POS X_BED_SIZE
-#define Y_MAX_POS Y_BED_SIZE
-#define Z_MAX_POS 200
+#define X_MAX_POS 260
+#define Y_MAX_POS 310
+#define Z_MAX_POS 295

 /**
 * Software Endstops
@@ -1193,7 +1274,7 @@
 #endif

 #if EITHER(MIN_SOFTWARE_ENDSTOPS, MAX_SOFTWARE_ENDSTOPS)
-  //#define SOFT_ENDSTOPS_MENU_ITEM  // Enable/Disable software endstops from the LCD
+  #define SOFT_ENDSTOPS_MENU_ITEM  // Enable/Disable software endstops from the LCD
 #endif

 /**
@@ -1209,7 +1290,7 @@
 * RAMPS-based boards use SERVO3_PIN for the first runout sensor.
 * For other boards you may need to define FIL_RUNOUT_PIN, FIL_RUNOUT2_PIN, etc.
 */
-//#define FILAMENT_RUNOUT_SENSOR
+#define FILAMENT_RUNOUT_SENSOR
 #if ENABLED(FILAMENT_RUNOUT_SENSOR)
  #define FIL_RUNOUT_ENABLED_DEFAULT true // Enable the sensor on startup. Override with M412 followed by M500.
  #define NUM_RUNOUT_SENSORS   1          // Number of sensors, up to one per extruder. Define a FIL_RUNOUT#_PIN for each.
@@ -1217,6 +1298,8 @@
  #define FIL_RUNOUT_STATE     LOW        // Pin state indicating that filament is NOT present.
  #define FIL_RUNOUT_PULLUP               // Use internal pullup for filament runout pins.
  //#define FIL_RUNOUT_PULLDOWN           // Use internal pulldown for filament runout pins.
+  //#define WATCH_ALL_RUNOUT_SENSORS      // Execute runout script on any triggering sensor, not only for the active extruder.
+                                          // This is automatically enabled for MIXING_EXTRUDERs.

  // Override individually if the runout sensors vary
  //#define FIL_RUNOUT1_STATE LOW
@@ -1251,14 +1334,15 @@
  //#define FIL_RUNOUT8_PULLUP
  //#define FIL_RUNOUT8_PULLDOWN

-  // Set one or more commands to execute on filament runout.
-  // (After 'M412 H' Marlin will ask the host to handle the process.)
+  // Commands to execute on filament runout.
+  // With multiple runout sensors use the %c placeholder for the current tool in commands (e.g., "M600 T%c")
+  // NOTE: After 'M412 H1' the host handles filament runout and this script does not apply.
  #define FILAMENT_RUNOUT_SCRIPT "M600"

  // After a runout is detected, continue printing this length of filament
  // before executing the runout script. Useful for a sensor at the end of
  // a feed tube. Requires 4 bytes SRAM per sensor, plus 4 bytes overhead.
-  //#define FILAMENT_RUNOUT_DISTANCE_MM 25
+  #define FILAMENT_RUNOUT_DISTANCE_MM 5

  #ifdef FILAMENT_RUNOUT_DISTANCE_MM
    // Enable this option to use an encoder disc that toggles the runout pin
@@ -1308,7 +1392,7 @@
 */
 //#define AUTO_BED_LEVELING_3POINT
 //#define AUTO_BED_LEVELING_LINEAR
-//#define AUTO_BED_LEVELING_BILINEAR
+#define AUTO_BED_LEVELING_BILINEAR
 //#define AUTO_BED_LEVELING_UBL
 //#define MESH_BED_LEVELING

@@ -1317,13 +1401,13 @@
 * these options to restore the prior leveling state or to always enable
 * leveling immediately after G28.
 */
-//#define RESTORE_LEVELING_AFTER_G28
+#define RESTORE_LEVELING_AFTER_G28
 //#define ENABLE_LEVELING_AFTER_G28

 /**
 * Auto-leveling needs preheating
 */
-//#define PREHEAT_BEFORE_LEVELING
+#define PREHEAT_BEFORE_LEVELING
 #if ENABLED(PREHEAT_BEFORE_LEVELING)
  #define LEVELING_NOZZLE_TEMP 120   // (°C) Only applies to E0 at this time
  #define LEVELING_BED_TEMP     50
@@ -1336,13 +1420,18 @@
 */
 //#define DEBUG_LEVELING_FEATURE

+#if ANY(MESH_BED_LEVELING, AUTO_BED_LEVELING_UBL, PROBE_MANUALLY)
+  // Set a height for the start of manual adjustment
+  #define MANUAL_PROBE_START_Z 0.2  // (mm) Comment out to use the last-measured height
+#endif
+
 #if ANY(MESH_BED_LEVELING, AUTO_BED_LEVELING_BILINEAR, AUTO_BED_LEVELING_UBL)
  // Gradually reduce leveling correction until a set height is reached,
  // at which point movement will be level to the machine's XY plane.
  // The height can be set with M420 Z<height>
  #define ENABLE_LEVELING_FADE_HEIGHT
  #if ENABLED(ENABLE_LEVELING_FADE_HEIGHT)
-    #define DEFAULT_LEVELING_FADE_HEIGHT 10.0 // (mm) Default fade height.
+    #define DEFAULT_LEVELING_FADE_HEIGHT 0.0 // (mm) Default fade height.
  #endif

  // For Cartesian machines, instead of dividing moves on mesh boundaries,
@@ -1370,7 +1459,7 @@
 #if EITHER(AUTO_BED_LEVELING_LINEAR, AUTO_BED_LEVELING_BILINEAR)

  // Set the number of grid points per dimension.
-  #define GRID_MAX_POINTS_X 3
+  #define GRID_MAX_POINTS_X 5
  #define GRID_MAX_POINTS_Y GRID_MAX_POINTS_X

  // Probe along the Y axis, advancing X after each column
@@ -1406,12 +1495,16 @@
  #define GRID_MAX_POINTS_X 10      // Don't use more than 15 points per axis, implementation limited.
  #define GRID_MAX_POINTS_Y GRID_MAX_POINTS_X

+  //#define UBL_HILBERT_CURVE       // Use Hilbert distribution for less travel when probing multiple points
+
  #define UBL_MESH_EDIT_MOVES_Z     // Sophisticated users prefer no movement of nozzle
  #define UBL_SAVE_ACTIVE_ON_M500   // Save the currently active mesh in the current slot on M500

  //#define UBL_Z_RAISE_WHEN_OFF_MESH 2.5 // When the nozzle is off the mesh, this value is used
                                          // as the Z-Height correction value.

+  //#define UBL_MESH_WIZARD         // Run several commands in a row to get a complete mesh
+
 #elif ENABLED(MESH_BED_LEVELING)

  //===========================================================================
@@ -1430,27 +1523,27 @@
 * Add a bed leveling sub-menu for ABL or MBL.
 * Include a guided procedure if manual probing is enabled.
 */
-//#define LCD_BED_LEVELING
+#define LCD_BED_LEVELING

 #if ENABLED(LCD_BED_LEVELING)
  #define MESH_EDIT_Z_STEP  0.025 // (mm) Step size while manually probing Z axis.
  #define LCD_PROBE_Z_RANGE 4     // (mm) Z Range centered on Z_MIN_POS for LCD Z adjustment
-  //#define MESH_EDIT_MENU        // Add a menu to edit mesh points
+  #define MESH_EDIT_MENU        // Add a menu to edit mesh points
 #endif

 // Add a menu item to move between bed corners for manual bed adjustment
-//#define LEVEL_BED_CORNERS
+#define LEVEL_BED_CORNERS

 #if ENABLED(LEVEL_BED_CORNERS)
  #define LEVEL_CORNERS_INSET_LFRB { 30, 30, 30, 30 } // (mm) Left, Front, Right, Back insets
  #define LEVEL_CORNERS_HEIGHT      0.0   // (mm) Z height of nozzle at leveling points
  #define LEVEL_CORNERS_Z_HOP       4.0   // (mm) Z height of nozzle between leveling points
  //#define LEVEL_CENTER_TOO              // Move to the center after the last corner
-  //#define LEVEL_CORNERS_USE_PROBE
+  #define LEVEL_CORNERS_USE_PROBE
  #if ENABLED(LEVEL_CORNERS_USE_PROBE)
    #define LEVEL_CORNERS_PROBE_TOLERANCE 0.1
    #define LEVEL_CORNERS_VERIFY_RAISED   // After adjustment triggers the probe, re-probe to verify
-    //#define LEVEL_CORNERS_AUDIO_FEEDBACK
+    #define LEVEL_CORNERS_AUDIO_FEEDBACK
  #endif

  /**
@@ -1584,12 +1677,12 @@
 *   M501 - Read settings from EEPROM. (i.e., Throw away unsaved changes)
 *   M502 - Revert settings to "factory" defaults. (Follow with M500 to init the EEPROM.)
 */
-//#define EEPROM_SETTINGS     // Persistent storage with M500 and M501
+#define EEPROM_SETTINGS     // Persistent storage with M500 and M501
 //#define DISABLE_M503        // Saves ~2700 bytes of PROGMEM. Disable for release!
 #define EEPROM_CHITCHAT       // Give feedback on EEPROM commands. Disable to save PROGMEM.
 #define EEPROM_BOOT_SILENT    // Keep M503 quiet and only give errors during first load
 #if ENABLED(EEPROM_SETTINGS)
-  //#define EEPROM_AUTO_INIT  // Init EEPROM automatically on any errors.
+  #define EEPROM_AUTO_INIT  // Init EEPROM automatically on any errors.
 #endif

 //
@@ -1620,11 +1713,13 @@
 #define PREHEAT_1_LABEL       "PLA"
 #define PREHEAT_1_TEMP_HOTEND 180
 #define PREHEAT_1_TEMP_BED     70
+#define PREHEAT_1_TEMP_CHAMBER 35
 #define PREHEAT_1_FAN_SPEED     0 // Value from 0 to 255

 #define PREHEAT_2_LABEL       "ABS"
 #define PREHEAT_2_TEMP_HOTEND 240
 #define PREHEAT_2_TEMP_BED    110
+#define PREHEAT_2_TEMP_CHAMBER 35
 #define PREHEAT_2_FAN_SPEED     0 // Value from 0 to 255

 /**
@@ -1638,11 +1733,11 @@
 *    P1  Raise the nozzle always to Z-park height.
 *    P2  Raise the nozzle by Z-park amount, limited to Z_MAX_POS.
 */
-//#define NOZZLE_PARK_FEATURE
+#define NOZZLE_PARK_FEATURE

 #if ENABLED(NOZZLE_PARK_FEATURE)
  // Specify a park position as { X, Y, Z_raise }
-  #define NOZZLE_PARK_POINT { (X_MIN_POS + 10), (Y_MAX_POS - 10), 20 }
+  #define NOZZLE_PARK_POINT { (X_MIN_POS + 10), (Y_MIN_POS + 10), 5 }
  //#define NOZZLE_PARK_X_ONLY          // X move only is required to park
  //#define NOZZLE_PARK_Y_ONLY          // Y move only is required to park
  #define NOZZLE_PARK_Z_RAISE_MIN   2   // (mm) Always raise Z by at least this distance
@@ -1846,7 +1941,7 @@
 * SD Card support is disabled by default. If your controller has an SD slot,
 * you must uncomment the following option or it won't work.
 */
-//#define SDSUPPORT
+#define SDSUPPORT

 /**
 * SD CARD: ENABLE CRC
@@ -1893,7 +1988,7 @@
 //
 //  Set this option if CLOCKWISE causes values to DECREASE
 //
-//#define REVERSE_ENCODER_DIRECTION
+#define REVERSE_ENCODER_DIRECTION

 //
 // This option reverses the encoder direction for navigating LCD menus.
@@ -1916,7 +2011,7 @@
 //
 // Add individual axis homing items (Home X, Home Y, and Home Z) to the LCD menu.
 //
-//#define INDIVIDUAL_AXIS_HOMING_MENU
+#define INDIVIDUAL_AXIS_HOMING_MENU

 //
 // SPEAKER/BUZZER
@@ -1924,7 +2019,7 @@
 // If you have a speaker that can produce tones, enable it here.
 // By default Marlin assumes you have a buzzer with a fixed frequency.
 //
-//#define SPEAKER
+#define SPEAKER

 //
 // The duration and frequency for the UI feedback sound.
@@ -1949,6 +2044,14 @@
 //
 //#define REPRAP_DISCOUNT_SMART_CONTROLLER

+//
+// GT2560 (YHCB2004) LCD Display
+//
+// Requires Testato, Koepel softwarewire library and
+// Andriy Golovnya's LiquidCrystal_AIP31068 library.
+//
+//#define YHCB2004
+
 //
 // Original RADDS LCD Display+Encoder+SDCardReader
 // http://doku.radds.org/dokumentation/lcd-display/
@@ -2097,7 +2200,12 @@
 // RepRapDiscount FULL GRAPHIC Smart Controller
 // https://reprap.org/wiki/RepRapDiscount_Full_Graphic_Smart_Controller
 //
-//#define REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER
+#define REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER
+
+//
+// K.3D Full Graphic Smart Controller
+//
+//#define K3D_FULL_GRAPHIC_SMART_CONTROLLER

 //
 // ReprapWorld Graphical LCD
@@ -2164,7 +2272,8 @@
 // MKS LCD12864A/B with graphic controller and SD support. Follows MKS_MINI_12864 pinout.
 // https://www.aliexpress.com/item/33018110072.html
 //
-//#define MKS_LCD12864
+//#define MKS_LCD12864A
+//#define MKS_LCD12864B

 //
 // FYSETC variant of the MINI12864 graphic controller with SD support
@@ -2236,7 +2345,7 @@
 //#define OLED_PANEL_TINYBOY2

 //
-// MKS OLED 1.3" 128×64 FULL GRAPHICS CONTROLLER
+// MKS OLED 1.3" 128×64 Full Graphics Controller
 // https://reprap.org/wiki/MKS_12864OLED
 //
 // Tiny, but very sharp OLED display
@@ -2245,7 +2354,7 @@
 //#define MKS_12864OLED_SSD1306  // Uses the SSD1306 controller

 //
-// Zonestar OLED 128×64 FULL GRAPHICS CONTROLLER
+// Zonestar OLED 128×64 Full Graphics Controller
 //
 //#define ZONESTAR_12864LCD           // Graphical (DOGM) with ST7920 controller
 //#define ZONESTAR_12864OLED          // 1.3" OLED with SH1106 controller (default)
@@ -2262,10 +2371,15 @@
 //#define OVERLORD_OLED

 //
-// FYSETC OLED 2.42" 128×64 FULL GRAPHICS CONTROLLER with WS2812 RGB
+// FYSETC OLED 2.42" 128×64 Full Graphics Controller with WS2812 RGB
 // Where to find : https://www.aliexpress.com/item/4000345255731.html
 //#define FYSETC_242_OLED_12864   // Uses the SSD1309 controller

+//
+// K.3D SSD1309 OLED 2.42" 128×64 Full Graphics Controller
+//
+//#define K3D_242_OLED_CONTROLLER   // Software SPI
+
 //=============================================================================
 //========================== Extensible UI Displays ===========================
 //=============================================================================
@@ -2279,6 +2393,11 @@
 //#define DGUS_LCD_UI_FYSETC
 //#define DGUS_LCD_UI_HIPRECY

+//#define DGUS_LCD_UI_MKS
+#if ENABLED(DGUS_LCD_UI_MKS)
+  #define USE_MKS_GREEN_UI
+#endif
+
 //
 // Touch-screen LCD for Malyan M200/M300 printers
 //
@@ -2303,6 +2422,14 @@
  //#define ANYCUBIC_LCD_DEBUG
 #endif

+//
+// 320x240 Nextion 2.8" serial TFT Resistive Touch Screen NX3224T028
+//
+//#define NEXTION_TFT
+#if ENABLED(NEXTION_TFT)
+  #define LCD_SERIAL_PORT 1  // Default is 1 for Nextion
+#endif
+
 //
 // Third-party or vendor-customized controller interfaces.
 // Sources should be installed in 'src/lcd/extui'.
@@ -2388,6 +2515,11 @@
 //
 //#define ANET_ET5_TFT35

+//
+// 1024x600, 7", RGB Stock Display from BIQU-BX
+//
+//#define BIQU_BX_TFT70
+
 //
 // Generic TFT with detailed options
 //
@@ -2444,7 +2576,7 @@
 //#define DWIN_CREALITY_LCD

 //
-// ADS7843/XPT2046 ADC Touchscreen such as ILI9341 2.8
+// Touch Screen Settings
 //
 //#define TOUCH_SCREEN
 #if ENABLED(TOUCH_SCREEN)
@@ -2579,6 +2711,7 @@
  // Use a single NeoPixel LED for static (background) lighting
  //#define NEOPIXEL_BKGD_LED_INDEX  0               // Index of the LED to use
  //#define NEOPIXEL_BKGD_COLOR { 255, 255, 255, 0 } // R, G, B, W
+  //#define NEOPIXEL_BKGD_ALWAYS_ON                  // Keep the backlight on when other NeoPixels are off
 #endif

 /**
@@ -219,7 +219,7 @@ else ifeq ($(HARDWARE_MOTHERBOARD),1111)
 else ifeq ($(HARDWARE_MOTHERBOARD),1112)
 # MKS GEN L
 else ifeq ($(HARDWARE_MOTHERBOARD),1113)
-# zrib V2.0 control board (Chinese knock off RAMPS replica)
+# zrib V2.0 control board (Chinese RAMPS replica)
 else ifeq ($(HARDWARE_MOTHERBOARD),1114)
 # BigTreeTech or BIQU KFB2.0
 else ifeq ($(HARDWARE_MOTHERBOARD),1115)
@@ -323,6 +323,8 @@ else ifeq ($(HARDWARE_MOTHERBOARD),1203)
 else ifeq ($(HARDWARE_MOTHERBOARD),1204)
 # abee Scoovo X9H
 else ifeq ($(HARDWARE_MOTHERBOARD),1205)
+# Rambo ThinkerV2
+else ifeq ($(HARDWARE_MOTHERBOARD),1206)

 #
 # Other ATmega1280, ATmega2560
@@ -991,5 +993,5 @@ clean:

 .PHONY: all build elf hex eep lss sym program coff extcoff clean depend sizebefore sizeafter

-# Automaticaly include the dependency files created by gcc
+# Automatically include the dependency files created by gcc
 -include ${patsubst %.o, %.d, ${OBJ}}
@@ -25,7 +25,7 @@
 #include "HAL.h"

 #ifdef USBCON
-  DefaultSerial MSerial(false, Serial);
+  DefaultSerial1 MSerial0(false, Serial);
  #ifdef BLUETOOTH
    BTSerial btSerial(false, bluetoothSerial);
  #endif
@@ -58,6 +58,15 @@ void HAL_init() {
  #endif
 }

+void HAL_reboot() {
+  #if ENABLED(USE_WATCHDOG)
+    while (1) { /* run out the watchdog */ }
+  #else
+    void (*resetFunc)() = 0;  // Declare resetFunc() at address 0
+    resetFunc();              // Jump to address 0
+  #endif
+}
+
 #if ENABLED(SDSUPPORT)

  #include "../../sd/SdFatUtil.h"
@@ -83,38 +83,45 @@ typedef int8_t pin_t;
 // Serial ports
 #ifdef USBCON
  #include "../../core/serial_hook.h"
-  typedef ForwardSerial0Type< decltype(Serial) > DefaultSerial;
-  extern DefaultSerial MSerial;
+  typedef ForwardSerial1Class< decltype(Serial) > DefaultSerial1;
+  extern DefaultSerial1 MSerial0;
  #ifdef BLUETOOTH
-    typedef ForwardSerial0Type< decltype(bluetoothSerial) > BTSerial;
+    typedef ForwardSerial1Class< decltype(bluetoothSerial) > BTSerial;
    extern BTSerial btSerial;
  #endif

-  #define MYSERIAL0 TERN(BLUETOOTH, btSerial, MSerial)
+  #define MYSERIAL1 TERN(BLUETOOTH, btSerial, MSerial0)
 #else
  #if !WITHIN(SERIAL_PORT, -1, 3)
-    #error "SERIAL_PORT must be from -1 to 3. Please update your configuration."
+    #error "SERIAL_PORT must be from 0 to 3, or -1 for USB Serial."
  #endif
-  #define MYSERIAL0 customizedSerial1
+  #define MYSERIAL1 customizedSerial1

  #ifdef SERIAL_PORT_2
    #if !WITHIN(SERIAL_PORT_2, -1, 3)
-      #error "SERIAL_PORT_2 must be from -1 to 3. Please update your configuration."
+      #error "SERIAL_PORT_2 must be from 0 to 3, or -1 for USB Serial."
    #endif
-    #define MYSERIAL1 customizedSerial2
+    #define MYSERIAL2 customizedSerial2
+  #endif
+
+  #ifdef SERIAL_PORT_3
+    #if !WITHIN(SERIAL_PORT_3, -1, 3)
+      #error "SERIAL_PORT_3 must be from 0 to 3, or -1 for USB Serial."
+    #endif
+    #define MYSERIAL3 customizedSerial3
  #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."
+    #error "MMU2_SERIAL_PORT must be from 0 to 3, or -1 for USB Serial."
  #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."
+    #error "LCD_SERIAL_PORT must be from 0 to 3, or -1 for USB Serial."
  #endif
  #define LCD_SERIAL lcdSerial
  #if HAS_DGUS_LCD
@@ -135,7 +142,7 @@ void HAL_init();
 inline void HAL_clear_reset_source() { MCUSR = 0; }
 inline uint8_t HAL_get_reset_source() { return MCUSR; }

-inline void HAL_reboot() {}  // reboot the board or restart the bootloader
+void HAL_reboot();

 #if GCC_VERSION <= 50000
  #pragma GCC diagnostic push
@@ -88,7 +88,7 @@ void spiBegin() {
  }

  /** SPI read data  */
-  void spiRead(uint8_t* buf, uint16_t nbyte) {
+  void spiRead(uint8_t *buf, uint16_t nbyte) {
    if (nbyte-- == 0) return;
    SPDR = 0xFF;
    for (uint16_t i = 0; i < nbyte; i++) {
@@ -107,7 +107,7 @@ void spiBegin() {
  }

  /** SPI send block  */
-  void spiSendBlock(uint8_t token, const uint8_t* buf) {
+  void spiSendBlock(uint8_t token, const uint8_t *buf) {
    SPDR = token;
    for (uint16_t i = 0; i < 512; i += 2) {
      while (!TEST(SPSR, SPIF)) { /* Intentionally left empty */ }
@@ -215,7 +215,7 @@ void spiBegin() {
  }

  // Soft SPI read data
-  void spiRead(uint8_t* buf, uint16_t nbyte) {
+  void spiRead(uint8_t *buf, uint16_t nbyte) {
    for (uint16_t i = 0; i < nbyte; i++)
      buf[i] = spiRec();
  }
@@ -242,7 +242,7 @@ void spiBegin() {
  }

  // Soft SPI send block
-  void spiSendBlock(uint8_t token, const uint8_t* buf) {
+  void spiSendBlock(uint8_t token, const uint8_t *buf) {
    spiSend(token);
    for (uint16_t i = 0; i < 512; i++)
      spiSend(buf[i]);
@@ -454,7 +454,7 @@ void MarlinSerial<Cfg>::flush() {
 }

 template<typename Cfg>
-size_t MarlinSerial<Cfg>::write(const uint8_t c) {
+void MarlinSerial<Cfg>::write(const uint8_t c) {
  if (Cfg::TX_SIZE == 0) {

    _written = true;
@@ -480,7 +480,7 @@ size_t MarlinSerial<Cfg>::write(const uint8_t c) {
      // location". This makes sure flush() won't return until the bytes
      // actually got written
      B_TXC = 1;
-      return 1;
+      return;
    }

    const uint8_t i = (tx_buffer.head + 1) & (Cfg::TX_SIZE - 1);
@@ -510,7 +510,6 @@ size_t MarlinSerial<Cfg>::write(const uint8_t c) {
    // Enable TX ISR - Non atomic, but it will eventually enable TX ISR
    B_UDRIE = 1;
  }
-  return 1;
 }

 template<typename Cfg>
@@ -566,9 +565,9 @@ ISR(SERIAL_REGNAME(USART, SERIAL_PORT, _UDRE_vect)) {
  MarlinSerial<MarlinSerialCfg<SERIAL_PORT>>::_tx_udr_empty_irq();
 }

-// Because of the template definition above, it's required to instantiate the template to have all method generated
+// Because of the template definition above, it's required to instantiate the template to have all methods generated
 template class MarlinSerial< MarlinSerialCfg<SERIAL_PORT> >;
-MSerialT customizedSerial1(MSerialT::HasEmergencyParser);
+MSerialT1 customizedSerial1(MSerialT1::HasEmergencyParser);

 #ifdef SERIAL_PORT_2

@@ -583,7 +582,24 @@ MSerialT customizedSerial1(MSerialT::HasEmergencyParser);

  template class MarlinSerial< MarlinSerialCfg<SERIAL_PORT_2> >;
  MSerialT2 customizedSerial2(MSerialT2::HasEmergencyParser);
-#endif
+
+#endif // SERIAL_PORT_2
+
+#ifdef SERIAL_PORT_3
+
+  // Hookup ISR handlers
+  ISR(SERIAL_REGNAME(USART, SERIAL_PORT_3, _RX_vect)) {
+    MarlinSerial<MarlinSerialCfg<SERIAL_PORT_3>>::store_rxd_char();
+  }
+
+  ISR(SERIAL_REGNAME(USART, SERIAL_PORT_3, _UDRE_vect)) {
+    MarlinSerial<MarlinSerialCfg<SERIAL_PORT_3>>::_tx_udr_empty_irq();
+  }
+
+  template class MarlinSerial< MarlinSerialCfg<SERIAL_PORT_3> >;
+  MSerialT3 customizedSerial3(MSerialT3::HasEmergencyParser);
+
+#endif // SERIAL_PORT_3

 #ifdef MMU2_SERIAL_PORT

@@ -596,8 +612,9 @@ MSerialT customizedSerial1(MSerialT::HasEmergencyParser);
  }

  template class MarlinSerial< MMU2SerialCfg<MMU2_SERIAL_PORT> >;
-  MSerialT3 mmuSerial(MSerialT3::HasEmergencyParser);
-#endif
+  MSerialMMU2 mmuSerial(MSerialMMU2::HasEmergencyParser);
+
+#endif // MMU2_SERIAL_PORT

 #ifdef LCD_SERIAL_PORT

@@ -610,7 +627,7 @@ MSerialT customizedSerial1(MSerialT::HasEmergencyParser);
  }

  template class MarlinSerial< LCDSerialCfg<LCD_SERIAL_PORT> >;
-  MSerialT4 lcdSerial(MSerialT4::HasEmergencyParser);
+  MSerialLCD lcdSerial(MSerialLCD::HasEmergencyParser);

  #if HAS_DGUS_LCD
    template<typename Cfg>
@@ -623,13 +640,13 @@ MSerialT customizedSerial1(MSerialT::HasEmergencyParser);
    }
  #endif

-#endif
+#endif // LCD_SERIAL_PORT

 #endif // !USBCON && (UBRRH || UBRR0H || UBRR1H || UBRR2H || UBRR3H)

 // For AT90USB targets use the UART for BT interfacing
 #if defined(USBCON) && ENABLED(BLUETOOTH)
-  MSerialT5 bluetoothSerial(false);
+  MSerialBT bluetoothSerial(false);
 #endif

 #endif // __AVR__
@@ -210,7 +210,7 @@
    static int read();
    static void flush();
    static ring_buffer_pos_t available();
-    static size_t write(const uint8_t c);
+    static void write(const uint8_t c);
    static void flushTX();
    #if HAS_DGUS_LCD
      static ring_buffer_pos_t get_tx_buffer_free();
@@ -238,66 +238,60 @@
    static constexpr bool MAX_RX_QUEUED     = ENABLED(SERIAL_STATS_MAX_RX_QUEUED);
  };

-  typedef Serial0Type< MarlinSerial< MarlinSerialCfg<SERIAL_PORT> > > MSerialT;
-  extern MSerialT customizedSerial1;
+  typedef Serial1Class< MarlinSerial< MarlinSerialCfg<SERIAL_PORT> > > MSerialT1;
+  extern MSerialT1 customizedSerial1;

  #ifdef SERIAL_PORT_2
-    typedef Serial0Type< MarlinSerial< MarlinSerialCfg<SERIAL_PORT_2> > > MSerialT2;
+    typedef Serial1Class< MarlinSerial< MarlinSerialCfg<SERIAL_PORT_2> > > MSerialT2;
    extern MSerialT2 customizedSerial2;
  #endif

+  #ifdef SERIAL_PORT_3
+    typedef Serial1Class< MarlinSerial< MarlinSerialCfg<SERIAL_PORT_3> > > MSerialT3;
+    extern MSerialT3 customizedSerial3;
+  #endif
+
 #endif // !USBCON

 #ifdef MMU2_SERIAL_PORT
  template <uint8_t serial>
  struct MMU2SerialCfg {
    static constexpr int PORT               = serial;
+    static constexpr unsigned int RX_SIZE   = 32;
+    static constexpr unsigned int TX_SIZE   = 32;
    static constexpr bool XONOFF            = false;
    static constexpr bool EMERGENCYPARSER   = false;
    static constexpr bool DROPPED_RX        = false;
    static constexpr bool RX_FRAMING_ERRORS = false;
    static constexpr bool MAX_RX_QUEUED     = false;
-    static constexpr unsigned int RX_SIZE   = 32;
-    static constexpr unsigned int TX_SIZE   = 32;
    static constexpr bool RX_OVERRUNS       = false;
  };

-  typedef Serial0Type< MarlinSerial< MMU2SerialCfg<MMU2_SERIAL_PORT> > > MSerialT3;
-  extern MSerialT3 mmuSerial;
+  typedef Serial1Class< MarlinSerial< MMU2SerialCfg<MMU2_SERIAL_PORT> > > MSerialMMU2;
+  extern MSerialMMU2 mmuSerial;
 #endif

 #ifdef LCD_SERIAL_PORT

  template <uint8_t serial>
  struct LCDSerialCfg {
-    static constexpr int PORT                 = serial;
-    static constexpr bool XONOFF              = false;
-    static constexpr bool EMERGENCYPARSER     = ENABLED(EMERGENCY_PARSER);
-    static constexpr bool DROPPED_RX          = false;
-    static constexpr bool RX_FRAMING_ERRORS   = false;
-    static constexpr bool MAX_RX_QUEUED       = false;
-    #if HAS_DGUS_LCD
-      static constexpr unsigned int RX_SIZE   = DGUS_RX_BUFFER_SIZE;
-      static constexpr unsigned int TX_SIZE   = DGUS_TX_BUFFER_SIZE;
-      static constexpr bool RX_OVERRUNS       = ENABLED(SERIAL_STATS_RX_BUFFER_OVERRUNS);
-    #elif EITHER(ANYCUBIC_LCD_I3MEGA, ANYCUBIC_LCD_CHIRON)
-      static constexpr unsigned int RX_SIZE   = 64;
-      static constexpr unsigned int TX_SIZE   = 128;
-      static constexpr bool RX_OVERRUNS       = false;
-    #else
-      static constexpr unsigned int RX_SIZE   = 64;
-      static constexpr unsigned int TX_SIZE   = 128;
-      static constexpr bool RX_OVERRUNS       = false
-    #endif
+    static constexpr int PORT               = serial;
+    static constexpr unsigned int RX_SIZE   = TERN(HAS_DGUS_LCD, DGUS_RX_BUFFER_SIZE,  64);
+    static constexpr unsigned int TX_SIZE   = TERN(HAS_DGUS_LCD, DGUS_TX_BUFFER_SIZE, 128);
+    static constexpr bool XONOFF            = false;
+    static constexpr bool EMERGENCYPARSER   = ENABLED(EMERGENCY_PARSER);
+    static constexpr bool DROPPED_RX        = false;
+    static constexpr bool RX_FRAMING_ERRORS = false;
+    static constexpr bool MAX_RX_QUEUED     = false;
+    static constexpr bool RX_OVERRUNS       = BOTH(HAS_DGUS_LCD, SERIAL_STATS_RX_BUFFER_OVERRUNS);
  };

-
-  typedef Serial0Type< MarlinSerial< LCDSerialCfg<LCD_SERIAL_PORT> > > MSerialT4;
-  extern MSerialT4 lcdSerial;
+  typedef Serial1Class< MarlinSerial< LCDSerialCfg<LCD_SERIAL_PORT> > > MSerialLCD;
+  extern MSerialLCD lcdSerial;
 #endif

 // Use the UART for Bluetooth in AT90USB configurations
 #if defined(USBCON) && ENABLED(BLUETOOTH)
-  typedef Serial0Type<HardwareSerial> MSerialT5;
-  extern MSerialT5 bluetoothSerial;
+  typedef Serial1Class<HardwareSerial> MSerialBT;
+  extern MSerialBT bluetoothSerial;
 #endif
@@ -40,13 +40,13 @@ bool PersistentStore::access_start()  { return true; }
 bool PersistentStore::access_finish() { return true; }

 bool PersistentStore::write_data(int &pos, const uint8_t *value, size_t size, uint16_t *crc) {
+  uint16_t written = 0;
  while (size--) {
    uint8_t * const p = (uint8_t * const)pos;
    uint8_t v = *value;
-    // EEPROM has only ~100,000 write cycles,
-    // so only write bytes that have changed!
-    if (v != eeprom_read_byte(p)) {
+    if (v != eeprom_read_byte(p)) { // EEPROM has only ~100,000 write cycles, so only write bytes that have changed!
      eeprom_write_byte(p, v);
+      if (++written & 0x7F) delay(2); else safe_delay(2); // Avoid triggering watchdog during long EEPROM writes
      if (eeprom_read_byte(p) != v) {
        SERIAL_ECHO_MSG(STR_ERR_EEPROM_WRITE);
        return true;
@@ -241,7 +241,7 @@ uint8_t extDigitalRead(const int8_t pin) {
 *
 * DC values -1.0 to 1.0. Negative duty cycle inverts the pulse.
 */
-uint16_t set_pwm_frequency_hz(const float &hz, const float dca, const float dcb, const float dcc) {
+uint16_t set_pwm_frequency_hz(const_float_t hz, const float dca, const float dcb, const float dcc) {
  float count = 0;
  if (hz > 0 && (dca || dcb || dcc)) {
    count = float(F_CPU) / hz;            // 1x prescaler, TOP for 16MHz base freq.
@@ -285,7 +285,7 @@ enum ClockSource2 : char {
 */

 // Determine which harware PWMs are already in use
-#define _PWM_CHK_FAN_B(P) (P == E0_AUTO_FAN_PIN || P == E1_AUTO_FAN_PIN || P == E2_AUTO_FAN_PIN || P == E3_AUTO_FAN_PIN || P == E4_AUTO_FAN_PIN || P == E5_AUTO_FAN_PIN || P == E6_AUTO_FAN_PIN || P == E7_AUTO_FAN_PIN || P == CHAMBER_AUTO_FAN_PIN)
+#define _PWM_CHK_FAN_B(P) (P == E0_AUTO_FAN_PIN || P == E1_AUTO_FAN_PIN || P == E2_AUTO_FAN_PIN || P == E3_AUTO_FAN_PIN || P == E4_AUTO_FAN_PIN || P == E5_AUTO_FAN_PIN || P == E6_AUTO_FAN_PIN || P == E7_AUTO_FAN_PIN || P == CHAMBER_AUTO_FAN_PIN || P == COOLER_AUTO_FAN_PIN)
 #if PIN_EXISTS(CONTROLLER_FAN)
  #define PWM_CHK_FAN_B(P) (_PWM_CHK_FAN_B(P) || P == CONTROLLER_FAN_PIN)
 #else
@@ -56,3 +56,10 @@
 #if BOTH(HAS_TMC_SW_SERIAL, MONITOR_DRIVER_STATUS)
  #error "MONITOR_DRIVER_STATUS causes performance issues when used with SoftwareSerial-connected drivers. Disable MONITOR_DRIVER_STATUS or use hardware serial to continue."
 #endif
+
+/**
+ * Postmortem debugging
+ */
+#if ENABLED(POSTMORTEM_DEBUGGING)
+  #error "POSTMORTEM_DEBUGGING is not supported on AVR boards."
+#endif
@@ -38,7 +38,7 @@
  // portModeRegister takes a different argument
  #define digitalPinToTimer_DEBUG(p) digitalPinToTimer(p)
  #define digitalPinToBitMask_DEBUG(p) digitalPinToBitMask(p)
-  #define digitalPinToPort_DEBUG(p) digitalPinToPort_Teensy(p)
+  #define digitalPinToPort_DEBUG(p) digitalPinToPort(p)
  #define GET_PINMODE(pin) (*portModeRegister(pin) & digitalPinToBitMask_DEBUG(pin))

 #elif AVR_ATmega2560_FAMILY_PLUS_70   // So we can access/display all the pins on boards using more than 70
@@ -1,342 +0,0 @@
-/**
- * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
- *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- *
- */
-#ifdef ARDUINO_ARCH_SAM
-
-#include "../../core/macros.h"
-#include "../../core/serial.h"
-
-#include "../shared/backtrace/unwinder.h"
-#include "../shared/backtrace/unwmemaccess.h"
-
-#include <stdarg.h>
-
-// Debug monitor that dumps to the Programming port all status when
-// an exception or WDT timeout happens - And then resets the board
-
-// All the Monitor routines must run with interrupts disabled and
-// under an ISR execution context. That is why we cannot reuse the
-// Serial interrupt routines or any C runtime, as we don't know the
-// state we are when running them
-
-// A SW memory barrier, to ensure GCC does not overoptimize loops
-#define sw_barrier() __asm__ volatile("": : :"memory");
-
-// (re)initialize UART0 as a monitor output to 250000,n,8,1
-static void TXBegin() {
-
-  // Disable UART interrupt in NVIC
-  NVIC_DisableIRQ( UART_IRQn );
-
-  // We NEED memory barriers to ensure Interrupts are actually disabled!
-  // ( https://dzone.com/articles/nvic-disabling-interrupts-on-arm-cortex-m-and-the )
-  __DSB();
-  __ISB();
-
-  // Disable clock
-  pmc_disable_periph_clk( ID_UART );
-
-  // Configure PMC
-  pmc_enable_periph_clk( ID_UART );
-
-  // Disable PDC channel
-  UART->UART_PTCR = UART_PTCR_RXTDIS | UART_PTCR_TXTDIS;
-
-  // Reset and disable receiver and transmitter
-  UART->UART_CR = UART_CR_RSTRX | UART_CR_RSTTX | UART_CR_RXDIS | UART_CR_TXDIS;
-
-  // Configure mode: 8bit, No parity, 1 bit stop
-  UART->UART_MR = UART_MR_CHMODE_NORMAL | US_MR_CHRL_8_BIT | US_MR_NBSTOP_1_BIT | UART_MR_PAR_NO;
-
-  // Configure baudrate (asynchronous, no oversampling) to BAUDRATE bauds
-  UART->UART_BRGR = (SystemCoreClock / (BAUDRATE << 4));
-
-  // Enable receiver and transmitter
-  UART->UART_CR = UART_CR_RXEN | UART_CR_TXEN;
-}
-
-// Send character through UART with no interrupts
-static void TX(char c) {
-  while (!(UART->UART_SR & UART_SR_TXRDY)) { WDT_Restart(WDT); sw_barrier(); };
-  UART->UART_THR = c;
-}
-
-// Send String through UART
-static void TX(const char* s) {
-  while (*s) TX(*s++);
-}
-
-static void TXDigit(uint32_t d) {
-  if (d < 10) TX((char)(d+'0'));
-  else if (d < 16) TX((char)(d+'A'-10));
-  else TX('?');
-}
-
-// Send Hex number thru UART
-static void TXHex(uint32_t v) {
-  TX("0x");
-  for (uint8_t i = 0; i < 8; i++, v <<= 4)
-    TXDigit((v >> 28) & 0xF);
-}
-
-// Send Decimal number thru UART
-static void TXDec(uint32_t v) {
-  if (!v) {
-    TX('0');
-    return;
-  }
-
-  char nbrs[14];
-  char *p = &nbrs[0];
-  while (v != 0) {
-    *p++ = '0' + (v % 10);
-    v /= 10;
-  }
-  do {
-    p--;
-    TX(*p);
-  } while (p != &nbrs[0]);
-}
-
-// Dump a backtrace entry
-static bool UnwReportOut(void* ctx, const UnwReport* bte) {
-  int* p = (int*)ctx;
-
-  (*p)++;
-  TX('#'); TXDec(*p); TX(" : ");
-  TX(bte->name?bte->name:"unknown"); TX('@'); TXHex(bte->function);
-  TX('+'); TXDec(bte->address - bte->function);
-  TX(" PC:");TXHex(bte->address); TX('\n');
-  return true;
-}
-
-#ifdef UNW_DEBUG
-  void UnwPrintf(const char* format, ...) {
-    char dest[256];
-    va_list argptr;
-    va_start(argptr, format);
-    vsprintf(dest, format, argptr);
-    va_end(argptr);
-    TX(&dest[0]);
-  }
-#endif
-
-/* Table of function pointers for passing to the unwinder */
-static const UnwindCallbacks UnwCallbacks = {
-  UnwReportOut,
-  UnwReadW,
-  UnwReadH,
-  UnwReadB
-  #ifdef UNW_DEBUG
-   , UnwPrintf
-  #endif
-};
-
-/**
- * HardFaultHandler_C:
- * This is called from the HardFault_HandlerAsm with a pointer the Fault stack
- * as the parameter. We can then read the values from the stack and place them
- * into local variables for ease of reading.
- * We then read the various Fault Status and Address Registers to help decode
- * cause of the fault.
- * The function ends with a BKPT instruction to force control back into the debugger
- */
-extern "C"
-void HardFault_HandlerC(unsigned long *sp, unsigned long lr, unsigned long cause) {
-
-  static const char* causestr[] = {
-    "NMI","Hard","Mem","Bus","Usage","Debug","WDT","RSTC"
-  };
-
-  UnwindFrame btf;
-
-  // Dump report to the Programming port (interrupts are DISABLED)
-  TXBegin();
-  TX("\n\n## Software Fault detected ##\n");
-  TX("Cause: "); TX(causestr[cause]); TX('\n');
-
-  TX("R0   : "); TXHex(((unsigned long)sp[0])); TX('\n');
-  TX("R1   : "); TXHex(((unsigned long)sp[1])); TX('\n');
-  TX("R2   : "); TXHex(((unsigned long)sp[2])); TX('\n');
-  TX("R3   : "); TXHex(((unsigned long)sp[3])); TX('\n');
-  TX("R12  : "); TXHex(((unsigned long)sp[4])); TX('\n');
-  TX("LR   : "); TXHex(((unsigned long)sp[5])); TX('\n');
-  TX("PC   : "); TXHex(((unsigned long)sp[6])); TX('\n');
-  TX("PSR  : "); TXHex(((unsigned long)sp[7])); TX('\n');
-
-  // Configurable Fault Status Register
-  // Consists of MMSR, BFSR and UFSR
-  TX("CFSR : "); TXHex((*((volatile unsigned long *)(0xE000ED28)))); TX('\n');
-
-  // Hard Fault Status Register
-  TX("HFSR : "); TXHex((*((volatile unsigned long *)(0xE000ED2C)))); TX('\n');
-
-  // Debug Fault Status Register
-  TX("DFSR : "); TXHex((*((volatile unsigned long *)(0xE000ED30)))); TX('\n');
-
-  // Auxiliary Fault Status Register
-  TX("AFSR : "); TXHex((*((volatile unsigned long *)(0xE000ED3C)))); TX('\n');
-
-  // Read the Fault Address Registers. These may not contain valid values.
-  // Check BFARVALID/MMARVALID to see if they are valid values
-  // MemManage Fault Address Register
-  TX("MMAR : "); TXHex((*((volatile unsigned long *)(0xE000ED34)))); TX('\n');
-
-  // Bus Fault Address Register
-  TX("BFAR : "); TXHex((*((volatile unsigned long *)(0xE000ED38)))); TX('\n');
-
-  TX("ExcLR: "); TXHex(lr); TX('\n');
-  TX("ExcSP: "); TXHex((unsigned long)sp); TX('\n');
-
-  btf.sp = ((unsigned long)sp) + 8*4; // The original stack pointer
-  btf.fp = btf.sp;
-  btf.lr = ((unsigned long)sp[5]);
-  btf.pc = ((unsigned long)sp[6]) | 1; // Force Thumb, as CORTEX only support it
-
-  // Perform a backtrace
-  TX("\nBacktrace:\n\n");
-  int ctr = 0;
-  UnwindStart(&btf, &UnwCallbacks, &ctr);
-
-  // Disable all NVIC interrupts
-  NVIC->ICER[0] = 0xFFFFFFFF;
-  NVIC->ICER[1] = 0xFFFFFFFF;
-
-  // Relocate VTOR table to default position
-  SCB->VTOR = 0;
-
-  // Disable USB
-  otg_disable();
-
-  // Restart watchdog
-  WDT_Restart(WDT);
-
-  // Reset controller
-  NVIC_SystemReset();
-  for (;;) WDT_Restart(WDT);
-}
-
-__attribute__((naked)) void NMI_Handler() {
-  __asm__ __volatile__ (
-    ".syntax unified" "\n\t"
-    A("tst lr, #4")
-    A("ite eq")
-    A("mrseq r0, msp")
-    A("mrsne r0, psp")
-    A("mov r1,lr")
-    A("mov r2,#0")
-    A("b HardFault_HandlerC")
-  );
-}
-
-__attribute__((naked)) void HardFault_Handler() {
-  __asm__ __volatile__ (
-    ".syntax unified" "\n\t"
-    A("tst lr, #4")
-    A("ite eq")
-    A("mrseq r0, msp")
-    A("mrsne r0, psp")
-    A("mov r1,lr")
-    A("mov r2,#1")
-    A("b HardFault_HandlerC")
-  );
-}
-
-__attribute__((naked)) void MemManage_Handler() {
-  __asm__ __volatile__ (
-    ".syntax unified" "\n\t"
-    A("tst lr, #4")
-    A("ite eq")
-    A("mrseq r0, msp")
-    A("mrsne r0, psp")
-    A("mov r1,lr")
-    A("mov r2,#2")
-    A("b HardFault_HandlerC")
-  );
-}
-
-__attribute__((naked)) void BusFault_Handler() {
-  __asm__ __volatile__ (
-    ".syntax unified" "\n\t"
-    A("tst lr, #4")
-    A("ite eq")
-    A("mrseq r0, msp")
-    A("mrsne r0, psp")
-    A("mov r1,lr")
-    A("mov r2,#3")
-    A("b HardFault_HandlerC")
-  );
-}
-
-__attribute__((naked)) void UsageFault_Handler() {
-  __asm__ __volatile__ (
-    ".syntax unified" "\n\t"
-    A("tst lr, #4")
-    A("ite eq")
-    A("mrseq r0, msp")
-    A("mrsne r0, psp")
-    A("mov r1,lr")
-    A("mov r2,#4")
-    A("b HardFault_HandlerC")
-  );
-}
-
-__attribute__((naked)) void DebugMon_Handler() {
-  __asm__ __volatile__ (
-    ".syntax unified" "\n\t"
-    A("tst lr, #4")
-    A("ite eq")
-    A("mrseq r0, msp")
-    A("mrsne r0, psp")
-    A("mov r1,lr")
-    A("mov r2,#5")
-    A("b HardFault_HandlerC")
-  );
-}
-
-/* This is NOT an exception, it is an interrupt handler - Nevertheless, the framing is the same */
-__attribute__((naked)) void WDT_Handler() {
-  __asm__ __volatile__ (
-    ".syntax unified" "\n\t"
-    A("tst lr, #4")
-    A("ite eq")
-    A("mrseq r0, msp")
-    A("mrsne r0, psp")
-    A("mov r1,lr")
-    A("mov r2,#6")
-    A("b HardFault_HandlerC")
-  );
-}
-
-__attribute__((naked)) void RSTC_Handler() {
-  __asm__ __volatile__ (
-    ".syntax unified" "\n\t"
-    A("tst lr, #4")
-    A("ite eq")
-    A("mrseq r0, msp")
-    A("mrsne r0, psp")
-    A("mov r1,lr")
-    A("mov r2,#7")
-    A("b HardFault_HandlerC")
-  );
-}
-
-#endif // ARDUINO_ARCH_SAM
@@ -40,6 +40,8 @@ uint16_t HAL_adc_result;
 // Public functions
 // ------------------------

+TERN_(POSTMORTEM_DEBUGGING, extern void install_min_serial());
+
 // HAL initialization task
 void HAL_init() {
  // Initialize the USB stack
@@ -47,6 +49,7 @@ void HAL_init() {
    OUT_WRITE(SDSS, HIGH);  // Try to set SDSS inactive before any other SPI users start up
  #endif
  usb_task_init();
+  TERN_(POSTMORTEM_DEBUGGING, install_min_serial()); // Install the min serial handler
 }

 // HAL idle task
@@ -74,6 +77,8 @@ uint8_t HAL_get_reset_source() {
  }
 }

+void HAL_reboot() { rstc_start_software_reset(RSTC); }
+
 void _delay_ms(const int delay_ms) {
  // Todo: port for Due?
  delay(delay_ms);
@@ -102,11 +107,18 @@ uint16_t HAL_adc_get_result() {
  return HAL_adc_result;
 }

-// Forward the default serial port
-DefaultSerial MSerial(false, Serial);
-
-DefaultSerial1 MSerial1(false, Serial1);
-DefaultSerial2 MSerial2(false, Serial2);
-DefaultSerial3 MSerial3(false, Serial3);
+// Forward the default serial ports
+#if USING_HW_SERIAL0
+  DefaultSerial1 MSerial0(false, Serial);
+#endif
+#if USING_HW_SERIAL1
+  DefaultSerial2 MSerial1(false, Serial1);
+#endif
+#if USING_HW_SERIAL2
+  DefaultSerial3 MSerial2(false, Serial2);
+#endif
+#if USING_HW_SERIAL3
+  DefaultSerial4 MSerial3(false, Serial3);
+#endif

 #endif // ARDUINO_ARCH_SAM
@@ -37,36 +37,44 @@
 #include <stdint.h>

 #include "../../core/serial_hook.h"
-typedef ForwardSerial0Type< decltype(Serial) > DefaultSerial;
-extern DefaultSerial MSerial;

-typedef ForwardSerial0Type< decltype(Serial1) > DefaultSerial1;
-typedef ForwardSerial0Type< decltype(Serial2) > DefaultSerial2;
-typedef ForwardSerial0Type< decltype(Serial3) > DefaultSerial3;
-extern DefaultSerial1 MSerial1;
-extern DefaultSerial2 MSerial2;
-extern DefaultSerial3 MSerial3;
+typedef ForwardSerial1Class< decltype(Serial) > DefaultSerial1;
+typedef ForwardSerial1Class< decltype(Serial1) > DefaultSerial2;
+typedef ForwardSerial1Class< decltype(Serial2) > DefaultSerial3;
+typedef ForwardSerial1Class< decltype(Serial3) > DefaultSerial4;
+extern DefaultSerial1 MSerial0;
+extern DefaultSerial2 MSerial1;
+extern DefaultSerial3 MSerial2;
+extern DefaultSerial4 MSerial3;

 #define _MSERIAL(X) MSerial##X
 #define MSERIAL(X) _MSERIAL(X)
-#define MSerial0 MSerial

-// Define MYSERIAL0/1 before MarlinSerial includes!
 #if SERIAL_PORT == -1 || ENABLED(EMERGENCY_PARSER)
-  #define MYSERIAL0 customizedSerial1
+  #define MYSERIAL1 customizedSerial1
 #elif WITHIN(SERIAL_PORT, 0, 3)
-  #define MYSERIAL0 MSERIAL(SERIAL_PORT)
+  #define MYSERIAL1 MSERIAL(SERIAL_PORT)
 #else
-  #error "The required SERIAL_PORT must be from -1 to 3. Please update your configuration."
+  #error "The required SERIAL_PORT must be from 0 to 3, or -1 for USB Serial."
 #endif

 #ifdef SERIAL_PORT_2
  #if SERIAL_PORT_2 == -1 || ENABLED(EMERGENCY_PARSER)
-    #define MYSERIAL1 customizedSerial2
+    #define MYSERIAL2 customizedSerial2
  #elif WITHIN(SERIAL_PORT_2, 0, 3)
-    #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
+    #define MYSERIAL2 MSERIAL(SERIAL_PORT_2)
  #else
-    #error "SERIAL_PORT_2 must be from -1 to 3. Please update your configuration."
+    #error "SERIAL_PORT_2 must be from 0 to 3, or -1 for USB Serial."
+  #endif
+#endif
+
+#ifdef SERIAL_PORT_3
+  #if SERIAL_PORT_3 == -1 || ENABLED(EMERGENCY_PARSER)
+    #define MYSERIAL3 customizedSerial3
+  #elif WITHIN(SERIAL_PORT_3, 0, 3)
+    #define MYSERIAL3 MSERIAL(SERIAL_PORT_3)
+  #else
+    #error "SERIAL_PORT_3 must be from 0 to 3, or -1 for USB Serial."
  #endif
 #endif

@@ -74,17 +82,15 @@ extern DefaultSerial3 MSerial3;
  #if WITHIN(MMU2_SERIAL_PORT, 0, 3)
    #define MMU2_SERIAL MSERIAL(MMU2_SERIAL_PORT)
  #else
-    #error "MMU2_SERIAL_PORT must be from 0 to 3. Please update your configuration."
+    #error "MMU2_SERIAL_PORT must be from 0 to 3."
  #endif
 #endif

 #ifdef LCD_SERIAL_PORT
-  #if LCD_SERIAL_PORT == -1
-    #define LCD_SERIAL lcdSerial
-  #elif WITHIN(LCD_SERIAL_PORT, 0, 3)
+  #if WITHIN(LCD_SERIAL_PORT, 0, 3)
    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
  #else
-    #error "LCD_SERIAL_PORT must be from -1 to 3. Please update your configuration."
+    #error "LCD_SERIAL_PORT must be from 0 to 3."
  #endif
 #endif

@@ -114,7 +120,7 @@ void sei();                     // Enable interrupts
 void HAL_clear_reset_source();  // clear reset reason
 uint8_t HAL_get_reset_source(); // get reset reason

-inline void HAL_reboot() {}  // reboot the board or restart the bootloader
+void HAL_reboot();

 //
 // ADC
@@ -0,0 +1,91 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#ifdef ARDUINO_ARCH_SAM
+
+#include "../../inc/MarlinConfigPre.h"
+
+#if ENABLED(POSTMORTEM_DEBUGGING)
+
+#include "../shared/HAL_MinSerial.h"
+
+#include <stdarg.h>
+
+static void TXBegin() {
+  // Disable UART interrupt in NVIC
+  NVIC_DisableIRQ( UART_IRQn );
+
+  // We NEED memory barriers to ensure Interrupts are actually disabled!
+  // ( https://dzone.com/articles/nvic-disabling-interrupts-on-arm-cortex-m-and-the )
+  __DSB();
+  __ISB();
+
+  // Disable clock
+  pmc_disable_periph_clk( ID_UART );
+
+  // Configure PMC
+  pmc_enable_periph_clk( ID_UART );
+
+  // Disable PDC channel
+  UART->UART_PTCR = UART_PTCR_RXTDIS | UART_PTCR_TXTDIS;
+
+  // Reset and disable receiver and transmitter
+  UART->UART_CR = UART_CR_RSTRX | UART_CR_RSTTX | UART_CR_RXDIS | UART_CR_TXDIS;
+
+  // Configure mode: 8bit, No parity, 1 bit stop
+  UART->UART_MR = UART_MR_CHMODE_NORMAL | US_MR_CHRL_8_BIT | US_MR_NBSTOP_1_BIT | UART_MR_PAR_NO;
+
+  // Configure baudrate (asynchronous, no oversampling) to BAUDRATE bauds
+  UART->UART_BRGR = (SystemCoreClock / (BAUDRATE << 4));
+
+  // Enable receiver and transmitter
+  UART->UART_CR = UART_CR_RXEN | UART_CR_TXEN;
+}
+
+// A SW memory barrier, to ensure GCC does not overoptimize loops
+#define sw_barrier() __asm__ volatile("": : :"memory");
+static void TX(char c) {
+  while (!(UART->UART_SR & UART_SR_TXRDY)) { WDT_Restart(WDT); sw_barrier(); };
+  UART->UART_THR = c;
+}
+
+void install_min_serial() {
+  HAL_min_serial_init = &TXBegin;
+  HAL_min_serial_out = &TX;
+}
+
+#if DISABLED(DYNAMIC_VECTORTABLE)
+extern "C" {
+  __attribute__((naked)) void JumpHandler_ASM() {
+    __asm__ __volatile__ (
+      "b CommonHandler_ASM\n"
+    );
+  }
+  void __attribute__((naked, alias("JumpHandler_ASM"))) HardFault_Handler();
+  void __attribute__((naked, alias("JumpHandler_ASM"))) BusFault_Handler();
+  void __attribute__((naked, alias("JumpHandler_ASM"))) UsageFault_Handler();
+  void __attribute__((naked, alias("JumpHandler_ASM"))) MemManage_Handler();
+  void __attribute__((naked, alias("JumpHandler_ASM"))) NMI_Handler();
+}
+#endif
+
+#endif // POSTMORTEM_DEBUGGING
+#endif // ARDUINO_ARCH_SAM
@@ -56,8 +56,8 @@
  #pragma GCC optimize (3)

  typedef uint8_t (*pfnSpiTransfer)(uint8_t b);
-  typedef void    (*pfnSpiRxBlock)(uint8_t* buf, uint32_t nbyte);
-  typedef void    (*pfnSpiTxBlock)(const uint8_t* buf, uint32_t nbyte);
+  typedef void    (*pfnSpiRxBlock)(uint8_t *buf, uint32_t nbyte);
+  typedef void    (*pfnSpiTxBlock)(const uint8_t *buf, uint32_t nbyte);

  /* ---------------- Macros to be able to access definitions from asm */
  #define _PORT(IO) DIO ##  IO ## _WPORT
@@ -270,7 +270,7 @@
  static pfnSpiTransfer spiTransferTx = (pfnSpiTransfer)spiTransferX;

  // Block transfers run at ~8 .. ~10Mhz - Tx version (Rx data discarded)
-  static void spiTxBlock0(const uint8_t* ptr, uint32_t todo) {
+  static void spiTxBlock0(const uint8_t *ptr, uint32_t todo) {
    uint32_t MOSI_PORT_PLUS30 = ((uint32_t) PORT(SD_MOSI_PIN)) + 0x30;  /* SODR of port */
    uint32_t MOSI_MASK = PIN_MASK(SD_MOSI_PIN);
    uint32_t SCK_PORT_PLUS30 = ((uint32_t) PORT(SD_SCK_PIN)) + 0x30;    /* SODR of port */
@@ -349,7 +349,7 @@
    );
  }

-  static void spiRxBlock0(uint8_t* ptr, uint32_t todo) {
+  static void spiRxBlock0(uint8_t *ptr, uint32_t todo) {
    uint32_t bin = 0;
    uint32_t work = 0;
    uint32_t BITBAND_MISO_PORT = BITBAND_ADDRESS( ((uint32_t)PORT(SD_MISO_PIN))+0x3C, PIN_SHIFT(SD_MISO_PIN));  /* PDSR of port in bitband area */
@@ -425,13 +425,13 @@
    );
  }

-  static void spiTxBlockX(const uint8_t* buf, uint32_t todo) {
+  static void spiTxBlockX(const uint8_t *buf, uint32_t todo) {
    do {
      (void)spiTransferTx(*buf++);
    } while (--todo);
  }

-  static void spiRxBlockX(uint8_t* buf, uint32_t todo) {
+  static void spiRxBlockX(uint8_t *buf, uint32_t todo) {
    do {
      *buf++ = spiTransferRx(0xFF);
    } while (--todo);
@@ -463,7 +463,7 @@
    return b;
  }

-  void spiRead(uint8_t* buf, uint16_t nbyte) {
+  void spiRead(uint8_t *buf, uint16_t nbyte) {
    if (nbyte) {
      _SS_WRITE(LOW);
      WRITE(SD_MOSI_PIN, HIGH); // Output 1s 1
@@ -478,7 +478,7 @@
    _SS_WRITE(HIGH);
  }

-  void spiSendBlock(uint8_t token, const uint8_t* buf) {
+  void spiSendBlock(uint8_t token, const uint8_t *buf) {
    _SS_WRITE(LOW);
    (void)spiTransferTx(token);
    spiTxBlock(buf, 512);
@@ -645,7 +645,7 @@
    }

    // Read from SPI into buffer
-    void spiRead(uint8_t* buf, uint16_t nbyte) {
+    void spiRead(uint8_t *buf, uint16_t nbyte) {
      if (!nbyte) return;
      --nbyte;
      for (int i = 0; i < nbyte; i++) {
@@ -668,7 +668,7 @@
      //DELAY_US(1U);
    }

-    void spiSend(const uint8_t* buf, size_t nbyte) {
+    void spiSend(const uint8_t *buf, size_t nbyte) {
      if (!nbyte) return;
      --nbyte;
      for (size_t i = 0; i < nbyte; i++) {
@@ -689,7 +689,7 @@
      FLUSH_RX();
    }

-    void spiSend(uint32_t chan, const uint8_t* buf, size_t nbyte) {
+    void spiSend(uint32_t chan, const uint8_t *buf, size_t nbyte) {
      if (!nbyte) return;
      --nbyte;
      for (size_t i = 0; i < nbyte; i++) {
@@ -702,7 +702,7 @@
    }

    // Write from buffer to SPI
-    void spiSendBlock(uint8_t token, const uint8_t* buf) {
+    void spiSendBlock(uint8_t token, const uint8_t *buf) {
      SPI0->SPI_TDR = (uint32_t)token | SPI_PCS(SPI_CHAN);
      WHILE_TX(0);
      //WHILE_RX(0);
@@ -801,19 +801,19 @@

    uint8_t spiRec() { return (uint8_t)spiTransfer(0xFF); }

-    void spiRead(uint8_t* buf, uint16_t nbyte) {
+    void spiRead(uint8_t *buf, uint16_t nbyte) {
      for (int i = 0; i < nbyte; i++)
        buf[i] = spiTransfer(0xFF);
    }

    void spiSend(uint8_t data) { spiTransfer(data); }

-    void spiSend(const uint8_t* buf, size_t nbyte) {
+    void spiSend(const uint8_t *buf, size_t nbyte) {
      for (uint16_t i = 0; i < nbyte; i++)
        spiTransfer(buf[i]);
    }

-    void spiSendBlock(uint8_t token, const uint8_t* buf) {
+    void spiSendBlock(uint8_t token, const uint8_t *buf) {
      spiTransfer(token);
      for (uint16_t i = 0; i < 512; i++)
        spiTransfer(buf[i]);
@@ -476,9 +476,9 @@ void MarlinSerial<Cfg>::flushTX() {


 // If not using the USB port as serial port
-#if SERIAL_PORT >= 0
+#if defined(SERIAL_PORT) && SERIAL_PORT >= 0
  template class MarlinSerial< MarlinSerialCfg<SERIAL_PORT> >;
-  MSerialT customizedSerial1(MarlinSerialCfg<SERIAL_PORT>::EMERGENCYPARSER);
+  MSerialT1 customizedSerial1(MarlinSerialCfg<SERIAL_PORT>::EMERGENCYPARSER);
 #endif

 #if defined(SERIAL_PORT_2) && SERIAL_PORT_2 >= 0
@@ -486,4 +486,9 @@ void MarlinSerial<Cfg>::flushTX() {
  MSerialT2 customizedSerial2(MarlinSerialCfg<SERIAL_PORT_2>::EMERGENCYPARSER);
 #endif

+#if defined(SERIAL_PORT_3) && SERIAL_PORT_3 >= 0
+  template class MarlinSerial< MarlinSerialCfg<SERIAL_PORT_3> >;
+  MSerialT3 customizedSerial3(MarlinSerialCfg<SERIAL_PORT_3>::EMERGENCYPARSER);
+#endif
+
 #endif // ARDUINO_ARCH_SAM
@@ -140,12 +140,17 @@ struct MarlinSerialCfg {
  static constexpr bool MAX_RX_QUEUED     = ENABLED(SERIAL_STATS_MAX_RX_QUEUED);
 };

-#if SERIAL_PORT >= 0
-  typedef Serial0Type< MarlinSerial< MarlinSerialCfg<SERIAL_PORT> > > MSerialT;
-  extern MSerialT customizedSerial1;
+#if defined(SERIAL_PORT) && SERIAL_PORT >= 0
+  typedef Serial1Class< MarlinSerial< MarlinSerialCfg<SERIAL_PORT> > > MSerialT1;
+  extern MSerialT1 customizedSerial1;
 #endif

 #if defined(SERIAL_PORT_2) && SERIAL_PORT_2 >= 0
-  typedef Serial0Type< MarlinSerial< MarlinSerialCfg<SERIAL_PORT_2> > > MSerialT2;
+  typedef Serial1Class< MarlinSerial< MarlinSerialCfg<SERIAL_PORT_2> > > MSerialT2;
  extern MSerialT2 customizedSerial2;
 #endif
+
+#if defined(SERIAL_PORT_3) && SERIAL_PORT_3 >= 0
+  typedef Serial1Class< MarlinSerial< MarlinSerialCfg<SERIAL_PORT_3> > > MSerialT3;
+  extern MSerialT3 customizedSerial3;
+#endif
@@ -19,13 +19,13 @@
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */
+#ifdef ARDUINO_ARCH_SAM

 /**
 * MarlinSerial_Due.cpp - Hardware serial library for Arduino DUE
 * Copyright (c) 2017 Eduardo José Tagle. All right reserved
 * Based on MarlinSerial for AVR, copyright (c) 2006 Nicholas Zambetti.  All right reserved.
 */
-#ifdef ARDUINO_ARCH_SAM

 #include "../../inc/MarlinConfig.h"

@@ -65,7 +65,7 @@ int MarlinSerialUSB::peek() {

  pending_char = udi_cdc_getc();

-  TERN_(EMERGENCY_PARSER, emergency_parser.update(static_cast<MSerialT*>(this)->emergency_state, (char)pending_char));
+  TERN_(EMERGENCY_PARSER, emergency_parser.update(static_cast<MSerialT1*>(this)->emergency_state, (char)pending_char));

  return pending_char;
 }
@@ -87,17 +87,16 @@ int MarlinSerialUSB::read() {

  int c = udi_cdc_getc();

-  TERN_(EMERGENCY_PARSER, emergency_parser.update(static_cast<MSerialT*>(this)->emergency_state, (char)c));
+  TERN_(EMERGENCY_PARSER, emergency_parser.update(static_cast<MSerialT1*>(this)->emergency_state, (char)c));

  return c;
 }

-bool MarlinSerialUSB::available() {
-    /* If Pending chars */
-  return pending_char >= 0 ||
-    /* or USB CDC enumerated and configured on the PC side and some
-       bytes where sent to us */
-      (usb_task_cdc_isenabled() && udi_cdc_is_rx_ready());
+int MarlinSerialUSB::available() {
+  if (pending_char > 0) return pending_char;
+  return pending_char == 0 ||
+    // or USB CDC enumerated and configured on the PC side and some bytes where sent to us */
+    (usb_task_cdc_isenabled() && udi_cdc_is_rx_ready());
 }

 void MarlinSerialUSB::flush() { }
@@ -130,10 +129,13 @@ size_t MarlinSerialUSB::write(const uint8_t c) {

 // Preinstantiate
 #if SERIAL_PORT == -1
-  MSerialT customizedSerial1(TERN0(EMERGENCY_PARSER, true));
+  MSerialT1 customizedSerial1(TERN0(EMERGENCY_PARSER, true));
 #endif
 #if SERIAL_PORT_2 == -1
-  MSerialT customizedSerial2(TERN0(EMERGENCY_PARSER, true));
+  MSerialT2 customizedSerial2(TERN0(EMERGENCY_PARSER, true));
+#endif
+#if SERIAL_PORT_3 == -1
+  MSerialT3 customizedSerial3(TERN0(EMERGENCY_PARSER, true));
 #endif

 #endif // HAS_USB_SERIAL
@@ -27,11 +27,9 @@
 */

 #include "../../inc/MarlinConfig.h"
-#if HAS_USB_SERIAL
-
-#include <WString.h>
 #include "../../core/serial_hook.h"

+#include <WString.h>

 struct MarlinSerialUSB {
  void begin(const long);
@@ -39,7 +37,7 @@ struct MarlinSerialUSB {
  int peek();
  int read();
  void flush();
-  bool available();
+  int available();
  size_t write(const uint8_t c);

  #if ENABLED(SERIAL_STATS_DROPPED_RX)
@@ -50,14 +48,18 @@ struct MarlinSerialUSB {
    FORCE_INLINE int rxMaxEnqueued() { return 0; }
  #endif
 };
-typedef Serial0Type<MarlinSerialUSB> MSerialT;

 #if SERIAL_PORT == -1
-  extern MSerialT customizedSerial1;
+  typedef Serial1Class<MarlinSerialUSB> MSerialT1;
+  extern MSerialT1 customizedSerial1;
 #endif

 #if SERIAL_PORT_2 == -1
-  extern MSerialT customizedSerial2;
+  typedef Serial1Class<MarlinSerialUSB> MSerialT2;
+  extern MSerialT2 customizedSerial2;
 #endif

-#endif // HAS_USB_SERIAL
+#if SERIAL_PORT_3 == -1
+  typedef Serial1Class<MarlinSerialUSB> MSerialT3;
+  extern MSerialT3 customizedSerial3;
+#endif
@@ -135,11 +135,11 @@ static uint8_t buffer[256] = {0},   // The RAM buffer to accumulate writes
 #define DEBUG_OUT ENABLED(EE_EMU_DEBUG)
 #include "../../core/debug_out.h"

-static void ee_Dump(const int page, const void* data) {
+static void ee_Dump(const int page, const void *data) {

  #ifdef EE_EMU_DEBUG

-    const uint8_t* c = (const uint8_t*) data;
+    const uint8_t *c = (const uint8_t*) data;
    char buffer[80];

    sprintf_P(buffer, PSTR("Page: %d (0x%04x)\n"), page, page);
@@ -181,7 +181,7 @@ static void ee_Dump(const int page, const void* data) {
 * @param data    (pointer to the data buffer)
 */
 __attribute__ ((long_call, section (".ramfunc")))
-static bool ee_PageWrite(uint16_t page, const void* data) {
+static bool ee_PageWrite(uint16_t page, const void *data) {

  uint16_t i;
  uint32_t addrflash = uint32_t(getFlashStorage(page));
@@ -293,8 +293,8 @@ static bool ee_PageWrite(uint16_t page, const void* data) {
      ee_Dump(-page, data);

      // Calculate count of changed bits
-      uint32_t* p1 = (uint32_t*)addrflash;
-      uint32_t* p2 = (uint32_t*)data;
+      uint32_t *p1 = (uint32_t*)addrflash;
+      uint32_t *p2 = (uint32_t*)data;
      int count = 0;
      for (i =0; i<PageSize >> 2; i++) {
        if (p1[i] != p2[i]) {
@@ -470,7 +470,7 @@ static uint8_t ee_Read(uint32_t address, bool excludeRAMBuffer=false) {
  for (int page = curPage - 1; page >= 0; --page) {

    // Get a pointer to the flash page
-    uint8_t* pflash = (uint8_t*)getFlashStorage(page + curGroup * PagesPerGroup);
+    uint8_t *pflash = (uint8_t*)getFlashStorage(page + curGroup * PagesPerGroup);

    uint16_t i = 0;
    while (i <= (PageSize - 4)) { /* (PageSize - 4) because otherwise, there is not enough room for data and headers */
@@ -550,7 +550,7 @@ static uint32_t ee_GetAddrRange(uint32_t address, bool excludeRAMBuffer=false) {
  for (int page = curPage - 1; page >= 0; --page) {

    // Get a pointer to the flash page
-    uint8_t* pflash = (uint8_t*)getFlashStorage(page + curGroup * PagesPerGroup);
+    uint8_t *pflash = (uint8_t*)getFlashStorage(page + curGroup * PagesPerGroup);

    uint16_t i = 0;
    while (i <= (PageSize - 4)) { /* (PageSize - 4) because otherwise, there is not enough room for data and headers */
@@ -589,7 +589,7 @@ static uint32_t ee_GetAddrRange(uint32_t address, bool excludeRAMBuffer=false) {
 }

 static bool ee_IsPageClean(int page) {
-  uint32_t* pflash = (uint32_t*) getFlashStorage(page);
+  uint32_t *pflash = (uint32_t*) getFlashStorage(page);
  for (uint16_t i = 0; i < (PageSize >> 2); ++i)
    if (*pflash++ != 0xFFFFFFFF) return false;
  return true;
@@ -599,7 +599,7 @@ static bool ee_Flush(uint32_t overrideAddress = 0xFFFFFFFF, uint8_t overrideData

  // Check if RAM buffer has something to be written
  bool isEmpty = true;
-  uint32_t* p = (uint32_t*) &buffer[0];
+  uint32_t *p = (uint32_t*) &buffer[0];
  for (uint16_t j = 0; j < (PageSize >> 2); j++) {
    if (*p++ != 0xFFFFFFFF) {
      isEmpty = false;
@@ -976,14 +976,13 @@ bool PersistentStore::access_start()  { ee_Init();  return true; }
 bool PersistentStore::access_finish() { ee_Flush(); return true; }

 bool PersistentStore::write_data(int &pos, const uint8_t *value, size_t size, uint16_t *crc) {
+  uint16_t written = 0;
  while (size--) {
    uint8_t * const p = (uint8_t * const)pos;
    uint8_t v = *value;
-    // EEPROM has only ~100,000 write cycles,
-    // so only write bytes that have changed!
-    if (v != ee_Read(uint32_t(p))) {
+    if (v != ee_Read(uint32_t(p))) { // EEPROM has only ~100,000 write cycles, so only write bytes that have changed!
      ee_Write(uint32_t(p), v);
-      delay(2);
+      if (++written & 0x7F) delay(2); else safe_delay(2); // Avoid triggering watchdog during long EEPROM writes
      if (ee_Read(uint32_t(p)) != v) {
        SERIAL_ECHO_MSG(STR_ERR_EEPROM_WRITE);
        return true;
@@ -42,14 +42,13 @@ bool PersistentStore::access_start()  { eeprom_init(); return true; }
 bool PersistentStore::access_finish() { return true; }

 bool PersistentStore::write_data(int &pos, const uint8_t *value, size_t size, uint16_t *crc) {
+  uint16_t written = 0;
  while (size--) {
    uint8_t * const p = (uint8_t * const)pos;
    uint8_t v = *value;
-    // EEPROM has only ~100,000 write cycles,
-    // so only write bytes that have changed!
-    if (v != eeprom_read_byte(p)) {
+    if (v != eeprom_read_byte(p)) { // EEPROM has only ~100,000 write cycles, so only write bytes that have changed!
      eeprom_write_byte(p, v);
-      delay(2);
+      if (++written & 0x7F) delay(2); else safe_delay(2); // Avoid triggering watchdog during long EEPROM writes
      if (eeprom_read_byte(p) != v) {
        SERIAL_ECHO_MSG(STR_ERR_EEPROM_WRITE);
        return true;
@@ -33,7 +33,7 @@
 * For ARDUINO_ARCH_SAM
 * Note the code here was specifically crafted by disassembling what GCC produces
 * out of it, so GCC is able to optimize it out as much as possible to the least
- * amount of instructions. Be very carefull if you modify them, as "clean code"
+ * amount of instructions. Be very careful if you modify them, as "clean code"
 * leads to less efficient compiled code!!
 */

@@ -57,5 +57,5 @@
 #endif

 #if HAS_TMC_SW_SERIAL
-  #error "TMC220x Software Serial is not supported on this platform."
+  #error "TMC220x Software Serial is not supported on the DUE platform."
 #endif
@@ -32,7 +32,7 @@ Ctrl_status sd_mmc_spi_test_unit_ready() {
 Ctrl_status sd_mmc_spi_read_capacity(uint32_t *nb_sector) {
  if (!IS_SD_INSERTED() || IS_SD_PRINTING() || IS_SD_FILE_OPEN() || !card.isMounted())
    return CTRL_NO_PRESENT;
-  *nb_sector = card.getSd2Card().cardSize() - 1;
+  *nb_sector = card.diskIODriver()->cardSize() - 1;
  return CTRL_GOOD;
 }

@@ -74,24 +74,24 @@ Ctrl_status sd_mmc_spi_usb_read_10(uint32_t addr, uint16_t nb_sector) {
  #endif

  // Start reading
-  if (!card.getSd2Card().readStart(addr))
+  if (!card.diskIODriver()->readStart(addr))
    return CTRL_FAIL;

  // For each specified sector
  while (nb_sector--) {

    // Read a sector
-    card.getSd2Card().readData(sector_buf);
+    card.diskIODriver()->readData(sector_buf);

    // RAM -> USB
    if (!udi_msc_trans_block(true, sector_buf, SD_MMC_BLOCK_SIZE, nullptr)) {
-      card.getSd2Card().readStop();
+      card.diskIODriver()->readStop();
      return CTRL_FAIL;
    }
  }

  // Stop reading
-  card.getSd2Card().readStop();
+  card.diskIODriver()->readStop();

  // Done
  return CTRL_GOOD;
@@ -113,7 +113,7 @@ Ctrl_status sd_mmc_spi_usb_write_10(uint32_t addr, uint16_t nb_sector) {
  }
  #endif

-  if (!card.getSd2Card().writeStart(addr, nb_sector))
+  if (!card.diskIODriver()->writeStart(addr, nb_sector))
    return CTRL_FAIL;

  // For each specified sector
@@ -121,16 +121,16 @@ Ctrl_status sd_mmc_spi_usb_write_10(uint32_t addr, uint16_t nb_sector) {

    // USB -> RAM
    if (!udi_msc_trans_block(false, sector_buf, SD_MMC_BLOCK_SIZE, nullptr)) {
-      card.getSd2Card().writeStop();
+      card.diskIODriver()->writeStop();
      return CTRL_FAIL;
    }

    // Write a sector
-    card.getSd2Card().writeData(sector_buf);
+    card.diskIODriver()->writeData(sector_buf);
  }

  // Stop writing
-  card.getSd2Card().writeStop();
+  card.diskIODriver()->writeStop();

  // Done
  return CTRL_GOOD;
@@ -675,11 +675,11 @@ iram_size_t udi_cdc_multi_write_buf(uint8_t port, const void* buf, iram_size_t s
 *   - \code // Waits and gets a value on CDC line
 	int udi_cdc_getc(void);
 	// Reads a RAM buffer on CDC line
-	iram_size_t udi_cdc_read_buf(int* buf, iram_size_t size);
+	iram_size_t udi_cdc_read_buf(int *buf, iram_size_t size);
 	// Puts a byte on CDC line
 	int udi_cdc_putc(int value);
 	// Writes a RAM buffer on CDC line
-	iram_size_t udi_cdc_write_buf(const int* buf, iram_size_t size); \endcode
+	iram_size_t udi_cdc_write_buf(const int *buf, iram_size_t size); \endcode
 *
 * \section udi_cdc_use_cases Advanced use cases
 * For more advanced use of the UDI CDC module, see the following use cases:
@@ -264,7 +264,7 @@ bool usb_task_extra_string(void) {
 ** Handle device requests that the ASF stack doesn't
 */
 bool usb_task_other_requests(void) {
-  uint8_t* ptr = 0;
+  uint8_t *ptr = 0;
  uint16_t size = 0;

  if (Udd_setup_type() == USB_REQ_TYPE_VENDOR) {
@@ -322,7 +322,7 @@ void usb_task_init(void) {
      char *sptr;

      // Patch in the filament diameter
-      sprintf_P(diam, PSTR("%d"), (int)((DEFAULT_NOMINAL_FILAMENT_DIA) * 1000.0));
+      itoa((int)((DEFAULT_NOMINAL_FILAMENT_DIA) * 1000), diam, 10);

      // And copy it to the proper place, expanding it to unicode
      sptr = &diam[0];
@@ -20,11 +20,10 @@
 *
 */

-#include "FlushableHardwareSerial.h"
-
 #ifdef ARDUINO_ARCH_ESP32

+#include "FlushableHardwareSerial.h"

-Serial0Type<FlushableHardwareSerial> flushableSerial(false, 0);
+Serial1Class<FlushableHardwareSerial> flushableSerial(false, 0);

-#endif // ARDUINO_ARCH_ESP32
+#endif
@@ -21,9 +21,9 @@
 */
 #pragma once

-#ifdef ARDUINO_ARCH_ESP32
-
 #include <HardwareSerial.h>
+
+#include "../shared/Marduino.h"
 #include "../../core/serial_hook.h"

 class FlushableHardwareSerial : public HardwareSerial {
@@ -31,6 +31,4 @@ public:
  FlushableHardwareSerial(int uart_nr) : HardwareSerial(uart_nr) {}
 };

-extern Serial0Type<FlushableHardwareSerial> flushableSerial;
-
-#endif // ARDUINO_ARCH_ESP32
+extern Serial1Class<FlushableHardwareSerial> flushableSerial;
@@ -41,7 +41,7 @@
 #endif

 #if ENABLED(ESP3D_WIFISUPPORT)
-  DefaultSerial MSerial(false, Serial2Socket);
+  DefaultSerial1 MSerial0(false, Serial2Socket);
 #endif

 // ------------------------
@@ -141,6 +141,8 @@ void HAL_clear_reset_source() { }

 uint8_t HAL_get_reset_source() { return rtc_get_reset_reason(1); }

+void HAL_reboot() { ESP.restart(); }
+
 void _delay_ms(int delay_ms) { delay(delay_ms); }

 // return free memory between end of heap (or end bss) and whatever is current
@@ -185,6 +187,7 @@ void HAL_adc_init() {
  TERN_(HAS_TEMP_ADC_7, adc3_set_attenuation(get_channel(TEMP_7_PIN), ADC_ATTEN_11db));
  TERN_(HAS_HEATED_BED, adc1_set_attenuation(get_channel(TEMP_BED_PIN), ADC_ATTEN_11db));
  TERN_(HAS_TEMP_CHAMBER, adc1_set_attenuation(get_channel(TEMP_CHAMBER_PIN), ADC_ATTEN_11db));
+  TERN_(HAS_TEMP_COOLER, adc1_set_attenuation(get_channel(TEMP_COOLER_PIN), ADC_ATTEN_11db));
  TERN_(FILAMENT_WIDTH_SENSOR, adc1_set_attenuation(get_channel(FILWIDTH_PIN), ADC_ATTEN_11db));

  // Note that adc2 is shared with the WiFi module, which has higher priority, so the conversion may fail.
@@ -51,15 +51,15 @@

 extern portMUX_TYPE spinlock;

-#define MYSERIAL0 flushableSerial
+#define MYSERIAL1 flushableSerial

 #if EITHER(WIFISUPPORT, ESP3D_WIFISUPPORT)
  #if ENABLED(ESP3D_WIFISUPPORT)
-    typedef ForwardSerial0Type< decltype(Serial2Socket) > DefaultSerial;
-    extern DefaultSerial MSerial;
-    #define MYSERIAL1 MSerial
+    typedef ForwardSerial1Class< decltype(Serial2Socket) > DefaultSerial1;
+    extern DefaultSerial1 MSerial0;
+    #define MYSERIAL2 MSerial0
  #else
-    #define MYSERIAL1 webSocketSerial
+    #define MYSERIAL2 webSocketSerial
  #endif
 #endif

@@ -101,7 +101,7 @@ void HAL_clear_reset_source();
 // reset reason
 uint8_t HAL_get_reset_source();

-inline void HAL_reboot() {}  // reboot the board or restart the bootloader
+void HAL_reboot();

 void _delay_ms(int delay);

@@ -85,7 +85,7 @@ uint8_t spiRec() {
  return returnByte;
 }

-void spiRead(uint8_t* buf, uint16_t nbyte) {
+void spiRead(uint8_t *buf, uint16_t nbyte) {
  SPI.beginTransaction(spiConfig);
  SPI.transferBytes(0, buf, nbyte);
  SPI.endTransaction();
@@ -97,7 +97,7 @@ void spiSend(uint8_t b) {
  SPI.endTransaction();
 }

-void spiSendBlock(uint8_t token, const uint8_t* buf) {
+void spiSendBlock(uint8_t token, const uint8_t *buf) {
  SPI.beginTransaction(spiConfig);
  SPI.transfer(token);
  SPI.writeBytes(const_cast<uint8_t*>(buf), 512);
@@ -29,7 +29,7 @@
 #include "wifi.h"
 #include <ESPAsyncWebServer.h>

-MSerialT webSocketSerial(false);
+MSerialWebSocketT webSocketSerial(false);
 AsyncWebSocket ws("/ws"); // TODO Move inside the class.

 // RingBuffer impl
@@ -137,7 +137,7 @@ size_t WebSocketSerial::write(const uint8_t c) {
  return ret;
 }

-size_t WebSocketSerial::write(const uint8_t* buffer, size_t size) {
+size_t WebSocketSerial::write(const uint8_t *buffer, size_t size) {
  size_t written = 0;
  for (size_t i = 0; i < size; i++)
    written += write(buffer[i]);
@@ -54,7 +54,7 @@ public:
  ring_buffer_pos_t read(uint8_t *buffer);
  void flush();
  ring_buffer_pos_t write(const uint8_t c);
-  ring_buffer_pos_t write(const uint8_t* buffer, ring_buffer_pos_t size);
+  ring_buffer_pos_t write(const uint8_t *buffer, ring_buffer_pos_t size);
 };

 class WebSocketSerial: public Stream {
@@ -70,7 +70,7 @@ public:
  int read();
  void flush();
  size_t write(const uint8_t c);
-  size_t write(const uint8_t* buffer, size_t size);
+  size_t write(const uint8_t *buffer, size_t size);

  #if ENABLED(SERIAL_STATS_DROPPED_RX)
    FORCE_INLINE uint32_t dropped() { return 0; }
@@ -81,5 +81,5 @@ public:
  #endif
 };

-typedef Serial0Type<WebSocketSerial> MSerialT;
-extern MSerialT webSocketSerial;
+typedef Serial1Class<WebSocketSerial> MSerialWebSocketT;
+extern MSerialWebSocketT webSocketSerial;
@@ -139,7 +139,7 @@ static void IRAM_ATTR i2s_intr_handler_default(void *arg) {
  I2S0.int_clr.val = I2S0.int_st.val; //clear pending interrupt
 }

-void stepperTask(void* parameter) {
+void stepperTask(void *parameter) {
  uint32_t remaining = 0;

  while (1) {
@@ -30,9 +30,13 @@
 #endif

 #if HAS_TMC_SW_SERIAL
-  #error "TMC220x Software Serial is not supported on this platform."
+  #error "TMC220x Software Serial is not supported on ESP32."
 #endif

 #if BOTH(WIFISUPPORT, ESP3D_WIFISUPPORT)
  #error "Only enable one WiFi option, either WIFISUPPORT or ESP3D_WIFISUPPORT."
 #endif
+
+#if ENABLED(POSTMORTEM_DEBUGGING)
+  #error "POSTMORTEM_DEBUGGING is not yet supported on ESP32."
+#endif
@@ -29,12 +29,6 @@

 #include HAL_PATH(.,HAL.h)

-#ifdef SERIAL_PORT_2
-  #define NUM_SERIAL 2
-#else
-  #define NUM_SERIAL 1
-#endif
-
 #define HAL_ADC_RANGE _BV(HAL_ADC_RESOLUTION)

 #ifndef I2C_ADDRESS
@@ -73,4 +73,6 @@ void HAL_pwm_init() {

 }

+void HAL_reboot() { /* Reset the application state and GPIO */ }
+
 #endif // __PLAT_LINUX__
@@ -61,7 +61,7 @@ uint8_t _getc();
 #define SHARED_SERVOS HAS_SERVOS

 extern MSerialT usb_serial;
-#define MYSERIAL0 usb_serial
+#define MYSERIAL1 usb_serial

 #define ST7920_DELAY_1 DELAY_NS(600)
 #define ST7920_DELAY_2 DELAY_NS(750)
@@ -107,7 +107,7 @@ uint16_t HAL_adc_get_result();
 inline void HAL_clear_reset_source(void) {}
 inline uint8_t HAL_get_reset_source(void) { return RST_POWER_ON; }

-inline void HAL_reboot() {}  // reboot the board or restart the bootloader
+void HAL_reboot(); // Reset the application state and GPIO

 /* ---------------- Delay in cycles */
 FORCE_INLINE static void DELAY_CYCLES(uint64_t x) {
@@ -35,5 +35,9 @@
 #endif

 #if HAS_TMC_SW_SERIAL
-  #error "TMC220x Software Serial is not supported on this platform."
+  #error "TMC220x Software Serial is not supported on LINUX."
+#endif
+
+#if ENABLED(POSTMORTEM_DEBUGGING)
+  #error "POSTMORTEM_DEBUGGING is not yet supported on LINUX."
 #endif
@@ -115,4 +115,4 @@ struct HalSerial {
  volatile bool host_connected;
 };

-typedef Serial0Type<HalSerial> MSerialT;
+typedef Serial1Class<HalSerial> MSerialT;
@@ -105,8 +105,8 @@ int main() {
  std::thread write_serial (write_serial_thread);
  std::thread read_serial (read_serial_thread);

-  #ifdef MYSERIAL0
-    MYSERIAL0.begin(BAUDRATE);
+  #ifdef MYSERIAL1
+    MYSERIAL1.begin(BAUDRATE);
    SERIAL_ECHOLNPGM("x86_64 Initialized");
    SERIAL_FLUSHTX();
  #endif
@@ -1,322 +0,0 @@
-/**
- * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
- *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- *
- */
-#ifdef TARGET_LPC1768
-
-#include "../../core/macros.h"
-#include "../../core/serial.h"
-#include <stdarg.h>
-
-#include "../shared/backtrace/unwinder.h"
-#include "../shared/backtrace/unwmemaccess.h"
-#include "watchdog.h"
-#include <debug_frmwrk.h>
-
-
-// Debug monitor that dumps to the Programming port all status when
-// an exception or WDT timeout happens - And then resets the board
-
-// All the Monitor routines must run with interrupts disabled and
-// under an ISR execution context. That is why we cannot reuse the
-// Serial interrupt routines or any C runtime, as we don't know the
-// state we are when running them
-
-// A SW memory barrier, to ensure GCC does not overoptimize loops
-#define sw_barrier() __asm__ volatile("": : :"memory");
-
-// (re)initialize UART0 as a monitor output to 250000,n,8,1
-static void TXBegin() {
-}
-
-// Send character through UART with no interrupts
-static void TX(char c) {
-  _DBC(c);
-}
-
-// Send String through UART
-static void TX(const char* s) {
-  while (*s) TX(*s++);
-}
-
-static void TXDigit(uint32_t d) {
-  if (d < 10) TX((char)(d+'0'));
-  else if (d < 16) TX((char)(d+'A'-10));
-  else TX('?');
-}
-
-// Send Hex number thru UART
-static void TXHex(uint32_t v) {
-  TX("0x");
-  for (uint8_t i = 0; i < 8; i++, v <<= 4)
-    TXDigit((v >> 28) & 0xF);
-}
-
-// Send Decimal number thru UART
-static void TXDec(uint32_t v) {
-  if (!v) {
-    TX('0');
-    return;
-  }
-
-  char nbrs[14];
-  char *p = &nbrs[0];
-  while (v != 0) {
-    *p++ = '0' + (v % 10);
-    v /= 10;
-  }
-  do {
-    p--;
-    TX(*p);
-  } while (p != &nbrs[0]);
-}
-
-// Dump a backtrace entry
-static bool UnwReportOut(void* ctx, const UnwReport* bte) {
-  int* p = (int*)ctx;
-
-  (*p)++;
-  TX('#'); TXDec(*p); TX(" : ");
-  TX(bte->name?bte->name:"unknown"); TX('@'); TXHex(bte->function);
-  TX('+'); TXDec(bte->address - bte->function);
-  TX(" PC:");TXHex(bte->address); TX('\n');
-  return true;
-}
-
-#ifdef UNW_DEBUG
-  void UnwPrintf(const char* format, ...) {
-    char dest[256];
-    va_list argptr;
-    va_start(argptr, format);
-    vsprintf(dest, format, argptr);
-    va_end(argptr);
-    TX(&dest[0]);
-  }
-#endif
-
-/* Table of function pointers for passing to the unwinder */
-static const UnwindCallbacks UnwCallbacks = {
-  UnwReportOut,
-  UnwReadW,
-  UnwReadH,
-  UnwReadB
-  #ifdef UNW_DEBUG
-   ,UnwPrintf
-  #endif
-};
-
-
-/**
- * HardFaultHandler_C:
- * This is called from the HardFault_HandlerAsm with a pointer the Fault stack
- * as the parameter. We can then read the values from the stack and place them
- * into local variables for ease of reading.
- * We then read the various Fault Status and Address Registers to help decode
- * cause of the fault.
- * The function ends with a BKPT instruction to force control back into the debugger
- */
-extern "C"
-void HardFault_HandlerC(unsigned long *sp, unsigned long lr, unsigned long cause) {
-
-  static const char* causestr[] = {
-    "NMI","Hard","Mem","Bus","Usage","Debug","WDT","RSTC"
-  };
-
-  UnwindFrame btf;
-
-  // Dump report to the Programming port (interrupts are DISABLED)
-  TXBegin();
-  TX("\n\n## Software Fault detected ##\n");
-  TX("Cause: "); TX(causestr[cause]); TX('\n');
-
-  TX("R0   : "); TXHex(((unsigned long)sp[0])); TX('\n');
-  TX("R1   : "); TXHex(((unsigned long)sp[1])); TX('\n');
-  TX("R2   : "); TXHex(((unsigned long)sp[2])); TX('\n');
-  TX("R3   : "); TXHex(((unsigned long)sp[3])); TX('\n');
-  TX("R12  : "); TXHex(((unsigned long)sp[4])); TX('\n');
-  TX("LR   : "); TXHex(((unsigned long)sp[5])); TX('\n');
-  TX("PC   : "); TXHex(((unsigned long)sp[6])); TX('\n');
-  TX("PSR  : "); TXHex(((unsigned long)sp[7])); TX('\n');
-
-  // Configurable Fault Status Register
-  // Consists of MMSR, BFSR and UFSR
-  TX("CFSR : "); TXHex((*((volatile unsigned long *)(0xE000ED28)))); TX('\n');
-
-  // Hard Fault Status Register
-  TX("HFSR : "); TXHex((*((volatile unsigned long *)(0xE000ED2C)))); TX('\n');
-
-  // Debug Fault Status Register
-  TX("DFSR : "); TXHex((*((volatile unsigned long *)(0xE000ED30)))); TX('\n');
-
-  // Auxiliary Fault Status Register
-  TX("AFSR : "); TXHex((*((volatile unsigned long *)(0xE000ED3C)))); TX('\n');
-
-  // Read the Fault Address Registers. These may not contain valid values.
-  // Check BFARVALID/MMARVALID to see if they are valid values
-  // MemManage Fault Address Register
-  TX("MMAR : "); TXHex((*((volatile unsigned long *)(0xE000ED34)))); TX('\n');
-
-  // Bus Fault Address Register
-  TX("BFAR : "); TXHex((*((volatile unsigned long *)(0xE000ED38)))); TX('\n');
-
-  TX("ExcLR: "); TXHex(lr); TX('\n');
-  TX("ExcSP: "); TXHex((unsigned long)sp); TX('\n');
-
-  btf.sp = ((unsigned long)sp) + 8*4; // The original stack pointer
-  btf.fp = btf.sp;
-  btf.lr = ((unsigned long)sp[5]);
-  btf.pc = ((unsigned long)sp[6]) | 1; // Force Thumb, as CORTEX only support it
-
-  // Perform a backtrace
-  TX("\nBacktrace:\n\n");
-  int ctr = 0;
-  UnwindStart(&btf, &UnwCallbacks, &ctr);
-
-  // Disable all NVIC interrupts
-  NVIC->ICER[0] = 0xFFFFFFFF;
-  NVIC->ICER[1] = 0xFFFFFFFF;
-
-  // Relocate VTOR table to default position
-  SCB->VTOR = 0;
-
-  // Clear cause of reset to prevent entering smoothie bootstrap
-  HAL_clear_reset_source();
-
-  // Restart watchdog
-  #if ENABLED(USE_WATCHDOG)
-    //WDT_Restart(WDT);
-    watchdog_init();
-  #endif
-
-  // Reset controller
-  NVIC_SystemReset();
-
-  // Nothing below here is compiled because NVIC_SystemReset loops forever
-
-  for (;;) { TERN_(USE_WATCHDOG, watchdog_init()); }
-}
-
-extern "C" {
-__attribute__((naked)) void NMI_Handler() {
-  __asm__ __volatile__ (
-    ".syntax unified" "\n\t"
-    A("tst lr, #4")
-    A("ite eq")
-    A("mrseq r0, msp")
-    A("mrsne r0, psp")
-    A("mov r1,lr")
-    A("mov r2,#0")
-    A("b HardFault_HandlerC")
-  );
-}
-
-__attribute__((naked)) void HardFault_Handler() {
-  __asm__ __volatile__ (
-    ".syntax unified" "\n\t"
-    A("tst lr, #4")
-    A("ite eq")
-    A("mrseq r0, msp")
-    A("mrsne r0, psp")
-    A("mov r1,lr")
-    A("mov r2,#1")
-    A("b HardFault_HandlerC")
-  );
-}
-
-__attribute__((naked)) void MemManage_Handler() {
-  __asm__ __volatile__ (
-    ".syntax unified" "\n\t"
-    A("tst lr, #4")
-    A("ite eq")
-    A("mrseq r0, msp")
-    A("mrsne r0, psp")
-    A("mov r1,lr")
-    A("mov r2,#2")
-    A("b HardFault_HandlerC")
-  );
-}
-
-__attribute__((naked)) void BusFault_Handler() {
-  __asm__ __volatile__ (
-    ".syntax unified" "\n\t"
-    A("tst lr, #4")
-    A("ite eq")
-    A("mrseq r0, msp")
-    A("mrsne r0, psp")
-    A("mov r1,lr")
-    A("mov r2,#3")
-    A("b HardFault_HandlerC")
-  );
-}
-
-__attribute__((naked)) void UsageFault_Handler() {
-  __asm__ __volatile__ (
-    ".syntax unified" "\n\t"
-    A("tst lr, #4")
-    A("ite eq")
-    A("mrseq r0, msp")
-    A("mrsne r0, psp")
-    A("mov r1,lr")
-    A("mov r2,#4")
-    A("b HardFault_HandlerC")
-  );
-}
-
-__attribute__((naked)) void DebugMon_Handler() {
-  __asm__ __volatile__ (
-    ".syntax unified" "\n\t"
-    A("tst lr, #4")
-    A("ite eq")
-    A("mrseq r0, msp")
-    A("mrsne r0, psp")
-    A("mov r1,lr")
-    A("mov r2,#5")
-    A("b HardFault_HandlerC")
-  );
-}
-
-/* This is NOT an exception, it is an interrupt handler - Nevertheless, the framing is the same */
-__attribute__((naked)) void WDT_IRQHandler() {
-  __asm__ __volatile__ (
-    ".syntax unified" "\n\t"
-    A("tst lr, #4")
-    A("ite eq")
-    A("mrseq r0, msp")
-    A("mrsne r0, psp")
-    A("mov r1,lr")
-    A("mov r2,#6")
-    A("b HardFault_HandlerC")
-  );
-}
-
-__attribute__((naked)) void RSTC_Handler() {
-  __asm__ __volatile__ (
-    ".syntax unified" "\n\t"
-    A("tst lr, #4")
-    A("ite eq")
-    A("mrseq r0, msp")
-    A("mrsne r0, psp")
-    A("mov r1,lr")
-    A("mov r2,#7")
-    A("b HardFault_HandlerC")
-  );
-}
-}
-#endif // TARGET_LPC1768
@@ -29,7 +29,7 @@
  #include "watchdog.h"
 #endif

-DefaultSerial USBSerial(false, UsbSerial);
+DefaultSerial1 USBSerial(false, UsbSerial);

 uint32_t HAL_adc_reading = 0;

@@ -67,7 +67,7 @@ void flashFirmware(const int16_t) {
  delay(500);          // Give OS time to disconnect
  USB_Connect(false);  // USB clear connection
  delay(1000);         // Give OS time to notice
-  NVIC_SystemReset();
+  HAL_reboot();
 }

 void HAL_clear_reset_source(void) {
@@ -81,4 +81,6 @@ uint8_t HAL_get_reset_source(void) {
  return RST_POWER_ON;
 }

+void HAL_reboot() { NVIC_SystemReset(); }
+
 #endif // TARGET_LPC1768
@@ -60,28 +60,37 @@ extern "C" volatile uint32_t _millis;
  #define ST7920_DELAY_3 DELAY_NS(750)
 #endif

-typedef ForwardSerial0Type< decltype(UsbSerial) > DefaultSerial;
-extern DefaultSerial USBSerial;
+typedef ForwardSerial1Class< decltype(UsbSerial) > DefaultSerial1;
+extern DefaultSerial1 USBSerial;

 #define _MSERIAL(X) MSerial##X
 #define MSERIAL(X) _MSERIAL(X)
-#define MSerial0 MSerial

 #if SERIAL_PORT == -1
-  #define MYSERIAL0 USBSerial
+  #define MYSERIAL1 USBSerial
 #elif WITHIN(SERIAL_PORT, 0, 3)
-  #define MYSERIAL0 MSERIAL(SERIAL_PORT)
+  #define MYSERIAL1 MSERIAL(SERIAL_PORT)
 #else
-  #error "SERIAL_PORT must be from -1 to 3. Please update your configuration."
+  #error "SERIAL_PORT must be from 0 to 3. You can also use -1 if the board supports Native USB."
 #endif

 #ifdef SERIAL_PORT_2
  #if SERIAL_PORT_2 == -1
-    #define MYSERIAL1 USBSerial
+    #define MYSERIAL2 USBSerial
  #elif WITHIN(SERIAL_PORT_2, 0, 3)
-    #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
+    #define MYSERIAL2 MSERIAL(SERIAL_PORT_2)
  #else
-    #error "SERIAL_PORT_2 must be from -1 to 3. Please update your configuration."
+    #error "SERIAL_PORT_2 must be from 0 to 3. You can also use -1 if the board supports Native USB."
+  #endif
+#endif
+
+#ifdef SERIAL_PORT_3
+  #if SERIAL_PORT_3 == -1
+    #define MYSERIAL3 USBSerial
+  #elif WITHIN(SERIAL_PORT_3, 0, 3)
+    #define MYSERIAL3 MSERIAL(SERIAL_PORT_3)
+  #else
+    #error "SERIAL_PORT_3 must be from 0 to 3. You can also use -1 if the board supports Native USB."
  #endif
 #endif

@@ -91,7 +100,7 @@ extern DefaultSerial 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."
+    #error "MMU2_SERIAL_PORT must be from 0 to 3. You can also use -1 if the board supports Native USB."
  #endif
 #endif

@@ -101,7 +110,10 @@ extern DefaultSerial USBSerial;
  #elif WITHIN(LCD_SERIAL_PORT, 0, 3)
    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
  #else
-    #error "LCD_SERIAL_PORT must be from -1 to 3. Please update your configuration."
+    #error "LCD_SERIAL_PORT must be from 0 to 3. You can also use -1 if the board supports Native USB."
+  #endif
+  #if HAS_DGUS_LCD
+    #define SERIAL_GET_TX_BUFFER_FREE() MSerial0.available()
  #endif
 #endif

@@ -216,4 +228,4 @@ void set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t v_size=255,
 void HAL_clear_reset_source(void);
 uint8_t HAL_get_reset_source(void);

-inline void HAL_reboot() {}  // reboot the board or restart the bootloader
+void HAL_reboot();
@@ -0,0 +1,51 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#ifdef TARGET_LPC1768
+
+#include "../../inc/MarlinConfig.h"
+#include "HAL.h"
+
+#if ENABLED(POSTMORTEM_DEBUGGING)
+
+#include "../shared/HAL_MinSerial.h"
+#include <debug_frmwrk.h>
+
+static void TX(char c) { _DBC(c); }
+void install_min_serial() { HAL_min_serial_out = &TX; }
+
+#if DISABLED(DYNAMIC_VECTORTABLE)
+extern "C" {
+  __attribute__((naked)) void JumpHandler_ASM() {
+    __asm__ __volatile__ (
+      "b CommonHandler_ASM\n"
+    );
+  }
+  void __attribute__((naked, alias("JumpHandler_ASM"))) HardFault_Handler();
+  void __attribute__((naked, alias("JumpHandler_ASM"))) BusFault_Handler();
+  void __attribute__((naked, alias("JumpHandler_ASM"))) UsageFault_Handler();
+  void __attribute__((naked, alias("JumpHandler_ASM"))) MemManage_Handler();
+  void __attribute__((naked, alias("JumpHandler_ASM"))) NMI_Handler();
+}
+#endif
+
+#endif // POSTMORTEM_DEBUGGING
+#endif // TARGET_LPC1768
@@ -93,12 +93,12 @@

  void spiSend(uint8_t b) { (void)spiTransfer(b); }

-  void spiSend(const uint8_t* buf, size_t nbyte) {
+  void spiSend(const uint8_t *buf, size_t nbyte) {
    for (uint16_t i = 0; i < nbyte; i++)
      (void)spiTransfer(buf[i]);
  }

-  void spiSendBlock(uint8_t token, const uint8_t* buf) {
+  void spiSendBlock(uint8_t token, const uint8_t *buf) {
    (void)spiTransfer(token);
    for (uint16_t i = 0; i < 512; i++)
      (void)spiTransfer(buf[i]);
@@ -135,13 +135,13 @@

  void spiSend(uint8_t b) { doio(b); }

-  void spiSend(const uint8_t* buf, size_t nbyte) {
+  void spiSend(const uint8_t *buf, size_t nbyte) {
    for (uint16_t i = 0; i < nbyte; i++) doio(buf[i]);
  }

  void spiSend(uint32_t chan, byte b) {}

-  void spiSend(uint32_t chan, const uint8_t* buf, size_t nbyte) {}
+  void spiSend(uint32_t chan, const uint8_t *buf, size_t nbyte) {}

  // Read single byte from SPI
  uint8_t spiRec() { return doio(0xFF); }
@@ -156,7 +156,7 @@
  uint8_t spiTransfer(uint8_t b) { return doio(b); }

  // Write from buffer to SPI
-  void spiSendBlock(uint8_t token, const uint8_t* buf) {
+  void spiSendBlock(uint8_t token, const uint8_t *buf) {
   (void)spiTransfer(token);
    for (uint16_t i = 0; i < 512; i++)
      (void)spiTransfer(buf[i]);
@@ -21,24 +21,51 @@
 */
 #ifdef TARGET_LPC1768

-#include "../../inc/MarlinConfigPre.h"
 #include "MarlinSerial.h"

-#if ANY_SERIAL_IS(0)
-  MSerialT MSerial(true, LPC_UART0);
-  extern "C" void UART0_IRQHandler() { MSerial.IRQHandler(); }
+#include "../../inc/MarlinConfig.h"
+
+#if USING_HW_SERIAL0
+  MarlinSerial _MSerial0(LPC_UART0);
+  MSerialT MSerial0(true, _MSerial0);
+  extern "C" void UART0_IRQHandler() { _MSerial0.IRQHandler(); }
 #endif
-#if ANY_SERIAL_IS(1)
-  MSerialT MSerial1(true, (LPC_UART_TypeDef *) LPC_UART1);
-  extern "C" void UART1_IRQHandler() { MSerial1.IRQHandler(); }
+#if USING_HW_SERIAL1
+  MarlinSerial _MSerial1((LPC_UART_TypeDef *) LPC_UART1);
+  MSerialT MSerial1(true, _MSerial1);
+  extern "C" void UART1_IRQHandler() { _MSerial1.IRQHandler(); }
 #endif
-#if ANY_SERIAL_IS(2)
-  MSerialT MSerial2(true, LPC_UART2);
-  extern "C" void UART2_IRQHandler() { MSerial2.IRQHandler(); }
+#if USING_HW_SERIAL2
+  MarlinSerial _MSerial2(LPC_UART2);
+  MSerialT MSerial2(true, _MSerial2);
+  extern "C" void UART2_IRQHandler() { _MSerial2.IRQHandler(); }
 #endif
-#if ANY_SERIAL_IS(3)
-  MSerialT MSerial3(true, LPC_UART3);
-  extern "C" void UART3_IRQHandler() { MSerial3.IRQHandler(); }
+#if USING_HW_SERIAL3
+  MarlinSerial _MSerial3(LPC_UART3);
+  MSerialT MSerial3(true, _MSerial3);
+  extern "C" void UART3_IRQHandler() { _MSerial3.IRQHandler(); }
+#endif
+
+#if ENABLED(EMERGENCY_PARSER)
+
+  bool MarlinSerial::recv_callback(const char c) {
+    // Need to figure out which serial port we are and react in consequence (Marlin does not have CONTAINER_OF macro)
+    if (false) {}
+    #if USING_HW_SERIAL0
+      else if (this == &_MSerial0) emergency_parser.update(MSerial0.emergency_state, c);
+    #endif
+    #if USING_HW_SERIAL1
+      else if (this == &_MSerial1) emergency_parser.update(MSerial1.emergency_state, c);
+    #endif
+    #if USING_HW_SERIAL2
+      else if (this == &_MSerial2) emergency_parser.update(MSerial2.emergency_state, c);
+    #endif
+    #if USING_HW_SERIAL3
+      else if (this == &_MSerial3) emergency_parser.update(MSerial3.emergency_state, c);
+    #endif
+    return true;
+  }
+
 #endif

 #endif // TARGET_LPC1768
@@ -47,15 +47,21 @@ public:
  void end() {}

  #if ENABLED(EMERGENCY_PARSER)
-    bool recv_callback(const char c) override {
-      emergency_parser.update(static_cast<Serial0Type<MarlinSerial> *>(this)->emergency_state, c);
-      return true; // do not discard character
-    }
+    bool recv_callback(const char c) override;
  #endif
 };

-typedef Serial0Type<MarlinSerial> MSerialT;
-extern MSerialT MSerial;
+// On LPC176x framework, HardwareSerial does not implement the same interface as Arduino's Serial, so overloads
+// of 'available' and 'read' method are not used in this multiple inheritance scenario.
+// Instead, use a ForwardSerial here that adapts the interface.
+typedef ForwardSerial1Class<MarlinSerial> MSerialT;
+extern MSerialT MSerial0;
 extern MSerialT MSerial1;
 extern MSerialT MSerial2;
 extern MSerialT MSerial3;
+
+// Consequently, we can't use a RuntimeSerial either. The workaround would be to use
+// a RuntimeSerial<ForwardSerial<MarlinSerial>> type here. Ignore for now until it's actually required.
+#if ENABLED(SERIAL_RUNTIME_HOOK)
+  #error "SERIAL_RUNTIME_HOOK is not yet supported for LPC176x."
+#endif
@@ -83,14 +83,13 @@ bool PersistentStore::access_finish() {
 static void debug_rw(const bool write, int &pos, const uint8_t *value, const size_t size, const FRESULT s, const size_t total=0) {
  PGM_P const rw_str = write ? PSTR("write") : PSTR("read");
  SERIAL_CHAR(' ');
-  serialprintPGM(rw_str);
+  SERIAL_ECHOPGM_P(rw_str);
  SERIAL_ECHOLNPAIR("_data(", pos, ",", value, ",", size, ", ...)");
  if (total) {
    SERIAL_ECHOPGM(" f_");
-    serialprintPGM(rw_str);
+    SERIAL_ECHOPGM_P(rw_str);
    SERIAL_ECHOPAIR("()=", s, "\n size=", size, "\n bytes_");
-    serialprintPGM(write ? PSTR("written=") : PSTR("read="));
-    SERIAL_ECHOLN(total);
+    SERIAL_ECHOLNPAIR_P(write ? PSTR("written=") : PSTR("read="), total);
  }
  else
    SERIAL_ECHOLNPAIR(" f_lseek()=", s);
@@ -42,25 +42,22 @@ bool PersistentStore::access_start()  { eeprom_init(); return true; }
 bool PersistentStore::access_finish() { return true; }

 bool PersistentStore::write_data(int &pos, const uint8_t *value, size_t size, uint16_t *crc) {
+  uint16_t written = 0;
  while (size--) {
    uint8_t v = *value;
-
-    // EEPROM has only ~100,000 write cycles,
-    // so only write bytes that have changed!
    uint8_t * const p = (uint8_t * const)pos;
-    if (v != eeprom_read_byte(p)) {
+    if (v != eeprom_read_byte(p)) { // EEPROM has only ~100,000 write cycles, so only write bytes that have changed!
      eeprom_write_byte(p, v);
+      if (++written & 0x7F) delay(2); else safe_delay(2); // Avoid triggering watchdog during long EEPROM writes
      if (eeprom_read_byte(p) != v) {
        SERIAL_ECHO_MSG(STR_ERR_EEPROM_WRITE);
        return true;
      }
    }
-
    crc16(crc, &v, 1);
    pos++;
    value++;
-  };
-
+  }
  return false;
 }

@@ -68,7 +65,6 @@ bool PersistentStore::read_data(int &pos, uint8_t *value, size_t size, uint16_t
  do {
    // Read from external EEPROM
    const uint8_t c = eeprom_read_byte((uint8_t*)pos);
-
    if (writing) *value = c;
    crc16(crc, &c, 1);
    pos++;
@@ -30,6 +30,5 @@
 // LPC1768 boards seem to lose steps when saving to EEPROM during print (issue #20785)
 // TODO: Which other boards are incompatible?
 #if defined(MCU_LPC1768) && PRINTCOUNTER_SAVE_INTERVAL > 0
-  #warning "To prevent step loss, motion will pause for PRINTCOUNTER auto-save."
  #define PRINTCOUNTER_SYNC 1
 #endif
@@ -92,7 +92,7 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
 #define ANY_TX(N,V...) DO(IS_TX##N,||,V)
 #define ANY_RX(N,V...) DO(IS_RX##N,||,V)

-#if ANY_SERIAL_IS(0)
+#if USING_HW_SERIAL0
  #define IS_TX0(P) (P == P0_02)
  #define IS_RX0(P) (P == P0_03)
  #if IS_TX0(TMC_SW_MISO) || IS_RX0(TMC_SW_MOSI)
@@ -106,7 +106,7 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
  #undef IS_RX0
 #endif

-#if ANY_SERIAL_IS(1)
+#if USING_HW_SERIAL1
  #define IS_TX1(P) (P == P0_15)
  #define IS_RX1(P) (P == P0_16)
  #define _IS_TX1_1 IS_TX1
@@ -127,7 +127,7 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
  #undef _IS_RX1_1
 #endif

-#if ANY_SERIAL_IS(2)
+#if USING_HW_SERIAL2
  #define IS_TX2(P) (P == P0_10)
  #define IS_RX2(P) (P == P0_11)
  #define _IS_TX2_1 IS_TX2
@@ -144,7 +144,7 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
    #error "Serial port pins (2) conflict with Z4 pins!"
  #elif ANY_RX(2, X_DIR_PIN, Y_DIR_PIN)
    #error "Serial port pins (2) conflict with other pins!"
-  #elif Y_HOME_DIR < 0 && IS_TX2(Y_STOP_PIN)
+  #elif Y_HOME_TO_MIN && IS_TX2(Y_STOP_PIN)
    #error "Serial port pins (2) conflict with Y endstop pin!"
  #elif HAS_CUSTOM_PROBE_PIN && IS_TX2(Z_MIN_PROBE_PIN)
    #error "Serial port pins (2) conflict with probe pin!"
@@ -161,7 +161,7 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
  #undef _IS_RX2_1
 #endif

-#if ANY_SERIAL_IS(3)
+#if USING_HW_SERIAL3
  #define PIN_IS_TX3(P) (PIN_EXISTS(P) && P##_PIN == P0_00)
  #define PIN_IS_RX3(P) (P##_PIN == P0_01)
  #if PIN_IS_TX3(X_MIN) || PIN_IS_RX3(X_MAX)
@@ -270,7 +270,7 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
 #endif

 #if ENABLED(SERIAL_STATS_MAX_RX_QUEUED)
-  #error "SERIAL_STATS_MAX_RX_QUEUED is not supported on this platform."
+  #error "SERIAL_STATS_MAX_RX_QUEUED is not supported on LPC176x."
 #elif ENABLED(SERIAL_STATS_DROPPED_RX)
-  #error "SERIAL_STATS_DROPPED_RX is not supported on this platform."
+  #error "SERIAL_STATS_DROPPED_RX is not supported on LPX176x."
 #endif
@@ -46,6 +46,8 @@ extern "C" {

 void SysTick_Callback() { disk_timerproc(); }

+TERN_(POSTMORTEM_DEBUGGING, extern void install_min_serial());
+
 void HAL_init() {

  // Init LEDs
@@ -115,7 +117,7 @@ void HAL_init() {
    PinCfg.Pinmode = 2;    // no pull-up/pull-down
    PINSEL_ConfigPin(&PinCfg);
    // now set CLKOUT_EN bit
-    LPC_SC->CLKOUTCFG |= (1<<8);
+    SBI(LPC_SC->CLKOUTCFG, 8);
  #endif

  USB_Init();                               // USB Initialization
@@ -123,9 +125,7 @@ void HAL_init() {
  delay(1000);                              // Give OS time to notice
  USB_Connect(true);

-  #if HAS_SD_HOST_DRIVE
-    MSC_SD_Init(0);                         // Enable USB SD card access
-  #endif
+  TERN_(HAS_SD_HOST_DRIVE, MSC_SD_Init(0)); // Enable USB SD card access

  const millis_t usb_timeout = millis() + 2000;
  while (!USB_Configuration && PENDING(millis(), usb_timeout)) {
@@ -137,6 +137,8 @@ void HAL_init() {
  }

  HAL_timer_init();
+
+  TERN_(POSTMORTEM_DEBUGGING, install_min_serial()); // Install the min serial handler
 }

 // HAL idle task
@@ -22,7 +22,7 @@

 #include "../../../inc/MarlinConfig.h"

-#if HAS_TFT_XPT2046 || HAS_TOUCH_BUTTONS
+#if HAS_TFT_XPT2046 || HAS_RES_TOUCH_BUTTONS

 #include "xpt2046.h"
 #include <SPI.h>
@@ -66,7 +66,7 @@
 void spiBegin();
 void spiInit(uint8_t spiRate);
 void spiSend(uint8_t b);
-void spiSend(const uint8_t* buf, size_t n);
+void spiSend(const uint8_t *buf, size_t n);

 static uint8_t rs_last_state = 255;

@@ -8,9 +8,7 @@ from __future__ import print_function
 target_filename = "FIRMWARE.CUR"
 target_drive = "REARM"

-import os
-import getpass
-import platform
+import os,getpass,platform

 current_OS = platform.system()
 Import("env")
@@ -22,102 +20,104 @@ def print_error(e):
 		  'or copy the firmware (.pio/build/%s/firmware.bin) manually to the appropriate disk\n' \
 		  %(e, env.get('PIOENV')))

-try:
-	#
-	# Find a disk for upload
-	#
-	upload_disk = 'Disk not found'
-	target_file_found = False
-	target_drive_found = False
-	if current_OS == 'Windows':
+def before_upload(source, target, env):
+	try:
 		#
-		# platformio.ini will accept this for a Windows upload port designation: 'upload_port = L:'
-		#   Windows - doesn't care about the disk's name, only cares about the drive letter
-		import subprocess
-		from ctypes import windll
-		import string
+		# Find a disk for upload
+		#
+		upload_disk = 'Disk not found'
+		target_file_found = False
+		target_drive_found = False
+		if current_OS == 'Windows':
+			#
+			# platformio.ini will accept this for a Windows upload port designation: 'upload_port = L:'
+			#   Windows - doesn't care about the disk's name, only cares about the drive letter
+			import subprocess,string
+			from ctypes import windll

-		# getting list of drives
-		# https://stackoverflow.com/questions/827371/is-there-a-way-to-list-all-the-available-drive-letters-in-python
-		drives = []
-		bitmask = windll.kernel32.GetLogicalDrives()
-		for letter in string.ascii_uppercase:
-			if bitmask & 1:
-				drives.append(letter)
-			bitmask >>= 1
+			# getting list of drives
+			# https://stackoverflow.com/questions/827371/is-there-a-way-to-list-all-the-available-drive-letters-in-python
+			drives = []
+			bitmask = windll.kernel32.GetLogicalDrives()
+			for letter in string.ascii_uppercase:
+				if bitmask & 1:
+					drives.append(letter)
+				bitmask >>= 1

-		for drive in drives:
-			final_drive_name = drive + ':\\'
-			# print ('disc check: {}'.format(final_drive_name))
-			try:
-				volume_info = str(subprocess.check_output('cmd /C dir ' + final_drive_name, stderr=subprocess.STDOUT))
-			except Exception as e:
-				print ('error:{}'.format(e))
-				continue
-			else:
-				if target_drive in volume_info and not target_file_found:  # set upload if not found target file yet
-					target_drive_found = True
-					upload_disk = final_drive_name
-				if target_filename in volume_info:
-					if not target_file_found:
+			for drive in drives:
+				final_drive_name = drive + ':\\'
+				# print ('disc check: {}'.format(final_drive_name))
+				try:
+					volume_info = str(subprocess.check_output('cmd /C dir ' + final_drive_name, stderr=subprocess.STDOUT))
+				except Exception as e:
+					print ('error:{}'.format(e))
+					continue
+				else:
+					if target_drive in volume_info and not target_file_found:  # set upload if not found target file yet
+						target_drive_found = True
 						upload_disk = final_drive_name
-					target_file_found = True
+					if target_filename in volume_info:
+						if not target_file_found:
+							upload_disk = final_drive_name
+						target_file_found = True

-	elif current_OS == 'Linux':
-		#
-		# platformio.ini will accept this for a Linux upload port designation: 'upload_port = /media/media_name/drive'
-		#
-		drives = os.listdir(os.path.join(os.sep, 'media', getpass.getuser()))
-		if target_drive in drives:  # If target drive is found, use it.
-			target_drive_found = True
-			upload_disk = os.path.join(os.sep, 'media', getpass.getuser(), target_drive) + os.sep
-		else:
+		elif current_OS == 'Linux':
+			#
+			# platformio.ini will accept this for a Linux upload port designation: 'upload_port = /media/media_name/drive'
+			#
+			drives = os.listdir(os.path.join(os.sep, 'media', getpass.getuser()))
+			if target_drive in drives:  # If target drive is found, use it.
+				target_drive_found = True
+				upload_disk = os.path.join(os.sep, 'media', getpass.getuser(), target_drive) + os.sep
+			else:
+				for drive in drives:
+					try:
+						files = os.listdir(os.path.join(os.sep, 'media', getpass.getuser(), drive))
+					except:
+						continue
+					else:
+						if target_filename in files:
+							upload_disk = os.path.join(os.sep, 'media', getpass.getuser(), drive) + os.sep
+							target_file_found = True
+							break
+			#
+			# set upload_port to drive if found
+			#
+
+			if target_file_found or target_drive_found:
+				env.Replace(
+					UPLOAD_FLAGS="-P$UPLOAD_PORT"
+				)
+
+		elif current_OS == 'Darwin':  # MAC
+			#
+			# platformio.ini will accept this for a OSX upload port designation: 'upload_port = /media/media_name/drive'
+			#
+			drives = os.listdir('/Volumes')  # human readable names
+			if target_drive in drives and not target_file_found:  # set upload if not found target file yet
+				target_drive_found = True
+				upload_disk = '/Volumes/' + target_drive + '/'
 			for drive in drives:
 				try:
-					files = os.listdir(os.path.join(os.sep, 'media', getpass.getuser(), drive))
+					filenames = os.listdir('/Volumes/' + drive + '/')   # will get an error if the drive is protected
 				except:
 					continue
 				else:
-					if target_filename in files:
-						upload_disk = os.path.join(os.sep, 'media', getpass.getuser(), drive) + os.sep
+					if target_filename in filenames:
+						if not target_file_found:
+							upload_disk = '/Volumes/' + drive + '/'
 						target_file_found = True
-						break
-		#
-		# set upload_port to drive if found
-		#

+		#
+		# Set upload_port to drive if found
+		#
 		if target_file_found or target_drive_found:
-			env.Replace(
-				UPLOAD_FLAGS="-P$UPLOAD_PORT"
-			)
+			env.Replace(UPLOAD_PORT=upload_disk)
+			print('\nUpload disk: ', upload_disk, '\n')
+		else:
+			print_error('Autodetect Error')

-	elif current_OS == 'Darwin':  # MAC
-		#
-		# platformio.ini will accept this for a OSX upload port designation: 'upload_port = /media/media_name/drive'
-		#
-		drives = os.listdir('/Volumes')  # human readable names
-		if target_drive in drives and not target_file_found:  # set upload if not found target file yet
-			target_drive_found = True
-			upload_disk = '/Volumes/' + target_drive + '/'
-		for drive in drives:
-			try:
-				filenames = os.listdir('/Volumes/' + drive + '/')   # will get an error if the drive is protected
-			except:
-				continue
-			else:
-				if target_filename in filenames:
-					if not target_file_found:
-						upload_disk = '/Volumes/' + drive + '/'
-					target_file_found = True
+	except Exception as e:
+		print_error(str(e))

-	#
-	# Set upload_port to drive if found
-	#
-	if target_file_found or target_drive_found:
-		env.Replace(UPLOAD_PORT=upload_disk)
-		print('\nUpload disk: ', upload_disk, '\n')
-	else:
-		print_error('Autodetect Error')
-
-except Exception as e:
-	print_error(str(e))
+env.AddPreAction("upload", before_upload)
@@ -29,8 +29,8 @@

 EmergencyParser::State emergency_state;

-bool CDC_RecvCallback(const char buffer) {
-  emergency_parser.update(emergency_state, buffer);
+bool CDC_RecvCallback(const char c) {
+  emergency_parser.update(emergency_state, c);
  return true;
 }

@@ -25,8 +25,21 @@
 #include <wiring_private.h>

 #ifdef ADAFRUIT_GRAND_CENTRAL_M4
-  DefaultSerial MSerial(false, Serial);
-  DefaultSerial1 MSerial1(false, Serial1);
+  #if USING_HW_SERIALUSB
+    DefaultSerial1 MSerial0(false, Serial);
+  #endif
+  #if USING_HW_SERIAL0
+    DefaultSerial2 MSerial1(false, Serial1);
+  #endif
+  #if USING_HW_SERIAL1
+    DefaultSerial3 MSerial2(false, Serial2);
+  #endif
+  #if USING_HW_SERIAL2
+    DefaultSerial4 MSerial3(false, Serial3);
+  #endif
+  #if USING_HW_SERIAL3
+    DefaultSerial5 MSerial4(false, Serial4);
+  #endif
 #endif

 // ------------------------
@@ -44,6 +57,7 @@
 #define GET_PROBE_ADC()           TERN(HAS_TEMP_PROBE,        PIN_TO_ADC(TEMP_PROBE_PIN),   -1)
 #define GET_BED_ADC()             TERN(HAS_TEMP_ADC_BED,      PIN_TO_ADC(TEMP_BED_PIN),     -1)
 #define GET_CHAMBER_ADC()         TERN(HAS_TEMP_ADC_CHAMBER,  PIN_TO_ADC(TEMP_CHAMBER_PIN), -1)
+#define GET_COOLER_ADC()          TERN(HAS_TEMP_ADC_COOLER,   PIN_TO_ADC(TEMP_COOLER_PIN),  -1)
 #define GET_FILAMENT_WIDTH_ADC()  TERN(FILAMENT_WIDTH_SENSOR, PIN_TO_ADC(FILWIDTH_PIN),     -1)
 #define GET_BUTTONS_ADC()         TERN(HAS_ADC_BUTTONS,       PIN_TO_ADC(ADC_KEYPAD_PIN),   -1)

@@ -53,6 +67,7 @@
  || GET_PROBE_ADC() == n          \
  || GET_BED_ADC() == n            \
  || GET_CHAMBER_ADC() == n        \
+  || GET_COOLER_ADC() == n         \
  || GET_FILAMENT_WIDTH_ADC() == n \
  || GET_BUTTONS_ADC() == n        \
 )
@@ -131,6 +146,9 @@ uint16_t HAL_adc_result;
    #if GET_CHAMBER_ADC() == 0
      TEMP_CHAMBER_PIN,
    #endif
+    #if GET_COOLER_ADC() == 0
+      TEMP_COOLER_PIN,
+    #endif
    #if GET_FILAMENT_WIDTH_ADC() == 0
      FILWIDTH_PIN,
    #endif
@@ -171,6 +189,9 @@ uint16_t HAL_adc_result;
    #if GET_CHAMBER_ADC() == 1
      TEMP_CHAMBER_PIN,
    #endif
+    #if GET_COOLER_ADC() == 1
+      TEMP_COOLER_PIN,
+    #endif
    #if GET_FILAMENT_WIDTH_ADC() == 1
      FILWIDTH_PIN,
    #endif
@@ -219,6 +240,9 @@ uint16_t HAL_adc_result;
      #if GET_CHAMBER_ADC() == 0
        { PIN_TO_INPUTCTRL(TEMP_CHAMBER_PIN) },
      #endif
+      #if GET_COOLER_ADC() == 0
+        { PIN_TO_INPUTCTRL(TEMP_COOLER_PIN) },
+      #endif
      #if GET_FILAMENT_WIDTH_ADC() == 0
        { PIN_TO_INPUTCTRL(FILWIDTH_PIN) },
      #endif
@@ -268,6 +292,9 @@ uint16_t HAL_adc_result;
      #if GET_CHAMBER_ADC() == 1
        { PIN_TO_INPUTCTRL(TEMP_CHAMBER_PIN) },
      #endif
+      #if GET_COOLER_ADC() == 1
+        { PIN_TO_INPUTCTRL(TEMP_COOLER_PIN) },
+      #endif
      #if GET_FILAMENT_WIDTH_ADC() == 1
        { PIN_TO_INPUTCTRL(FILWIDTH_PIN) },
      #endif
@@ -409,6 +436,8 @@ uint8_t HAL_get_reset_source() {
 }
 #pragma pop_macro("WDT")

+void HAL_reboot() { NVIC_SystemReset(); }
+
 extern "C" {
  void * _sbrk(int incr);

@@ -32,52 +32,56 @@
  #include "MarlinSerial_AGCM4.h"

  // Serial ports
-  typedef ForwardSerial0Type< decltype(Serial) > DefaultSerial;
-  extern DefaultSerial MSerial;
-  typedef ForwardSerial0Type< decltype(Serial1) > DefaultSerial1;
-  extern DefaultSerial1 MSerial1;
-
-  // MYSERIAL0 required before MarlinSerial includes!
+  typedef ForwardSerial1Class< decltype(Serial) > DefaultSerial1;
+  typedef ForwardSerial1Class< decltype(Serial1) > DefaultSerial2;
+  typedef ForwardSerial1Class< decltype(Serial2) > DefaultSerial3;
+  typedef ForwardSerial1Class< decltype(Serial3) > DefaultSerial4;
+  typedef ForwardSerial1Class< decltype(Serial4) > DefaultSerial5;
+  extern DefaultSerial1 MSerial0;
+  extern DefaultSerial2 MSerial1;
+  extern DefaultSerial3 MSerial2;
+  extern DefaultSerial4 MSerial3;
+  extern DefaultSerial5 MSerial4;

  #define __MSERIAL(X) MSerial##X
  #define _MSERIAL(X) __MSERIAL(X)
  #define MSERIAL(X) _MSERIAL(INCREMENT(X))

  #if SERIAL_PORT == -1
-    #define MYSERIAL0 MSerial
+    #define MYSERIAL1 MSerial0
  #elif WITHIN(SERIAL_PORT, 0, 3)
-    #define MYSERIAL0 MSERIAL(SERIAL_PORT)
+    #define MYSERIAL1 MSERIAL(SERIAL_PORT)
  #else
-    #error "SERIAL_PORT must be from -1 to 3. Please update your configuration."
+    #error "SERIAL_PORT must be from 0 to 3. You can also use -1 if the board supports Native USB."
  #endif

  #ifdef SERIAL_PORT_2
    #if SERIAL_PORT_2 == -1
-      #define MYSERIAL1 MSerial
+      #define MYSERIAL2 MSerial0
    #elif WITHIN(SERIAL_PORT_2, 0, 3)
-      #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
+      #define MYSERIAL2 MSERIAL(SERIAL_PORT_2)
    #else
-      #error "SERIAL_PORT_2 must be from -1 to 3. Please update your configuration."
+      #error "SERIAL_PORT_2 must be from 0 to 3. You can also use -1 if the board supports Native USB."
    #endif
  #endif

  #ifdef MMU2_SERIAL_PORT
    #if MMU2_SERIAL_PORT == -1
-      #define MMU2_SERIAL MSerial
+      #define MMU2_SERIAL MSerial0
    #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."
+      #error "MMU2_SERIAL_PORT must be from 0 to 3. You can also use -1 if the board supports Native USB."
    #endif
  #endif

  #ifdef LCD_SERIAL_PORT
    #if LCD_SERIAL_PORT == -1
-      #define LCD_SERIAL MSerial
+      #define LCD_SERIAL MSerial0
    #elif WITHIN(LCD_SERIAL_PORT, 0, 3)
      #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
    #else
-      #error "LCD_SERIAL_PORT must be from -1 to 3. Please update your configuration."
+      #error "LCD_SERIAL_PORT must be from 0 to 3. You can also use -1 if the board supports Native USB."
    #endif
  #endif

@@ -103,7 +107,7 @@ typedef int8_t pin_t;
 void HAL_clear_reset_source();  // clear reset reason
 uint8_t HAL_get_reset_source(); // get reset reason

-inline void HAL_reboot() {}  // reboot the board or restart the bootloader
+void HAL_reboot();

 //
 // ADC
@@ -103,7 +103,7 @@
   * @param  nbyte Number of bytes to receive.
   * @return Nothing
   */
-  void spiRead(uint8_t* buf, uint16_t nbyte) {
+  void spiRead(uint8_t *buf, uint16_t nbyte) {
    if (nbyte == 0) return;
    memset(buf, 0xFF, nbyte);
    sdSPI.beginTransaction(spiConfig);
@@ -132,7 +132,7 @@
   *
   * @details Uses DMA
   */
-  void spiSendBlock(uint8_t token, const uint8_t* buf) {
+  void spiSendBlock(uint8_t token, const uint8_t *buf) {
    sdSPI.beginTransaction(spiConfig);
    sdSPI.transfer(token);
    sdSPI.transfer((uint8_t*)buf, nullptr, 512);
@@ -27,7 +27,7 @@

 #include "../../inc/MarlinConfig.h"

-#if ANY_SERIAL_IS(1)
+#if USING_HW_SERIAL1
  UartT Serial2(false, &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 ANY_SERIAL_IS(2)
+#if USING_HW_SERIAL2
  UartT Serial3(false, &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 ANY_SERIAL_IS(3)
+#if USING_HW_SERIAL3
  UartT Serial4(false, &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(); }
@@ -22,7 +22,7 @@

 #include "../../core/serial_hook.h"

-typedef Serial0Type<Uart> UartT;
+typedef Serial1Class<Uart> UartT;

 extern UartT Serial2;
 extern UartT Serial3;
@@ -41,12 +41,13 @@ bool PersistentStore::access_start()  { eeprom_init(); return true; }
 bool PersistentStore::access_finish() { return true; }

 bool PersistentStore::write_data(int &pos, const uint8_t *value, size_t size, uint16_t *crc) {
+  uint16_t written = 0;
  while (size--) {
    const uint8_t v = *value;
    uint8_t * const p = (uint8_t * const)pos;
-    if (v != eeprom_read_byte(p)) {
+    if (v != eeprom_read_byte(p)) { // EEPROM has only ~100,000 write cycles, so only write bytes that have changed!
      eeprom_write_byte(p, v);
-      delay(2);
+      if (++written & 0x7F) delay(2); else safe_delay(2); // Avoid triggering watchdog during long EEPROM writes
      if (eeprom_read_byte(p) != v) {
        SERIAL_ECHO_MSG(STR_ERR_EEPROM_WRITE);
        return true;
@@ -50,3 +50,7 @@
 #if ENABLED(FAST_PWM_FAN) || SPINDLE_LASER_FREQUENCY
  #error "Features requiring Hardware PWM (FAST_PWM_FAN, SPINDLE_LASER_FREQUENCY) are not yet supported on SAMD51."
 #endif
+
+#if ENABLED(POSTMORTEM_DEBUGGING)
+  #error "POSTMORTEM_DEBUGGING is not yet supported on AGCM4."
+#endif
@@ -29,7 +29,7 @@
 #include "../shared/Delay.h"

 #ifdef USBCON
-  DefaultSerial MSerial(false, SerialUSB);
+  DefaultSerial1 MSerial0(false, SerialUSB);
 #endif

 #if ENABLED(SRAM_EEPROM_EMULATION)
@@ -57,10 +57,18 @@ uint16_t HAL_adc_result;
 // Public functions
 // ------------------------

+TERN_(POSTMORTEM_DEBUGGING, extern void install_min_serial());
+
 // HAL initialization task
 void HAL_init() {
  FastIO_init();

+  // Ensure F_CPU is a constant expression.
+  // If the compiler breaks here, it means that delay code that should compute at compile time will not work.
+  // So better safe than sorry here.
+  constexpr int cpuFreq = F_CPU;
+  UNUSED(cpuFreq);
+
  #if ENABLED(SDSUPPORT) && DISABLED(SDIO_SUPPORT) && (defined(SDSS) && SDSS != -1)
    OUT_WRITE(SDSS, HIGH); // Try to set SDSS inactive before any other SPI users start up
  #endif
@@ -83,9 +91,17 @@ void HAL_init() {
    USB_Hook_init();
  #endif

+  TERN_(POSTMORTEM_DEBUGGING, install_min_serial()); // Install the min serial handler
+
  #if HAS_SD_HOST_DRIVE
    MSC_SD_init();                         // Enable USB SD card access
  #endif
+
+  #if PIN_EXISTS(USB_CONNECT)
+    OUT_WRITE(USB_CONNECT_PIN, !USB_CONNECT_INVERTING);  // USB clear connection
+    delay(1000);                                         // Give OS time to notice
+    WRITE(USB_CONNECT_PIN, USB_CONNECT_INVERTING);
+  #endif
 }

 // HAL idle task
@@ -123,6 +139,8 @@ uint8_t HAL_get_reset_source() {
  ;
 }

+void HAL_reboot() { NVIC_SystemReset(); }
+
 void _delay_ms(const int delay_ms) { delay(delay_ms); }

 extern "C" {
@@ -137,8 +155,8 @@ extern "C" {
 void HAL_adc_start_conversion(const uint8_t adc_pin) { HAL_adc_result = analogRead(adc_pin); }
 uint16_t HAL_adc_get_result() { return HAL_adc_result; }

-// Reset the system (to initiate a firmware flash)
-void flashFirmware(const int16_t) { NVIC_SystemReset(); }
+// Reset the system to initiate a firmware flash
+void flashFirmware(const int16_t) { HAL_reboot(); }

 // Maple Compatibility
 volatile uint32_t systick_uptime_millis = 0;
@@ -37,54 +37,64 @@

 #include <stdint.h>

+//
+// Serial Ports
+//
 #ifdef USBCON
  #include <USBSerial.h>
  #include "../../core/serial_hook.h"
-  typedef ForwardSerial0Type< decltype(SerialUSB) > DefaultSerial;
-  extern DefaultSerial MSerial;
+  typedef ForwardSerial1Class< decltype(SerialUSB) > DefaultSerial1;
+  extern DefaultSerial1 MSerial0;
 #endif

-// ------------------------
-// Defines
-// ------------------------
 #define _MSERIAL(X) MSerial##X
 #define MSERIAL(X) _MSERIAL(X)

 #if SERIAL_PORT == -1
-  #define MYSERIAL0 MSerial
+  #define MYSERIAL1 MSerial0
 #elif WITHIN(SERIAL_PORT, 1, 6)
-  #define MYSERIAL0 MSERIAL(SERIAL_PORT)
+  #define MYSERIAL1 MSERIAL(SERIAL_PORT)
 #else
-  #error "SERIAL_PORT must be -1 or from 1 to 6. Please update your configuration."
+  #error "SERIAL_PORT must be from 1 to 6. You can also use -1 if the board supports Native USB."
 #endif

 #ifdef SERIAL_PORT_2
  #if SERIAL_PORT_2 == -1
-    #define MYSERIAL1 MSerial
+    #define MYSERIAL2 MSerial0
  #elif WITHIN(SERIAL_PORT_2, 1, 6)
-    #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
+    #define MYSERIAL2 MSERIAL(SERIAL_PORT_2)
  #else
-    #error "SERIAL_PORT_2 must be -1 or from 1 to 6. Please update your configuration."
+    #error "SERIAL_PORT_2 must be from 1 to 6. You can also use -1 if the board supports Native USB."
+  #endif
+#endif
+
+#ifdef SERIAL_PORT_3
+  #if SERIAL_PORT_3 == -1
+    #define MYSERIAL3 MSerial0
+  #elif WITHIN(SERIAL_PORT_3, 1, 6)
+    #define MYSERIAL3 MSERIAL(SERIAL_PORT_3)
+  #else
+    #error "SERIAL_PORT_3 must be from 1 to 6. You can also use -1 if the board supports Native USB."
  #endif
 #endif

 #ifdef MMU2_SERIAL_PORT
  #if MMU2_SERIAL_PORT == -1
-    #define MMU2_SERIAL MSerial
+    #define MMU2_SERIAL MSerial0
  #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."
+    #error "MMU2_SERIAL_PORT must be from 1 to 6. You can also use -1 if the board supports Native USB."
  #endif
 #endif

 #ifdef LCD_SERIAL_PORT
  #if LCD_SERIAL_PORT == -1
-    #define LCD_SERIAL MSerial
+    #define LCD_SERIAL MSerial0
  #elif WITHIN(LCD_SERIAL_PORT, 1, 6)
    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
  #else
-    #error "LCD_SERIAL_PORT must be -1 or from 1 to 6. Please update your configuration."
+    #error "LCD_SERIAL_PORT must be from 1 to 6. You can also use -1 if the board supports Native USB."
  #endif
  #if HAS_DGUS_LCD
    #define SERIAL_GET_TX_BUFFER_FREE() LCD_SERIAL.availableForWrite()
@@ -144,7 +154,7 @@ void HAL_clear_reset_source();
 // Reset reason
 uint8_t HAL_get_reset_source();

-inline void HAL_reboot() {}  // reboot the board or restart the bootloader
+void HAL_reboot();

 void _delay_ms(const int delay);

@@ -0,0 +1,152 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2017 Victor Perez
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#if defined(ARDUINO_ARCH_STM32) && !defined(STM32GENERIC)
+
+#include "../../inc/MarlinConfigPre.h"
+
+#if ENABLED(POSTMORTEM_DEBUGGING)
+
+#include "../shared/HAL_MinSerial.h"
+#include "watchdog.h"
+
+/* Instruction Synchronization Barrier */
+#define isb() __asm__ __volatile__ ("isb" : : : "memory")
+
+/* Data Synchronization Barrier */
+#define dsb() __asm__ __volatile__ ("dsb" : : : "memory")
+
+// Dumb mapping over the registers of a USART device on STM32
+struct USARTMin {
+  volatile uint32_t SR;
+  volatile uint32_t DR;
+  volatile uint32_t BRR;
+  volatile uint32_t CR1;
+  volatile uint32_t CR2;
+};
+
+#if WITHIN(SERIAL_PORT, 1, 6)
+  // Depending on the CPU, the serial port is different for USART1
+  static const uintptr_t regsAddr[] = {
+    TERN(STM32F1xx, 0x40013800, 0x40011000), // USART1
+    0x40004400, // USART2
+    0x40004800, // USART3
+    0x40004C00, // UART4_BASE
+    0x40005000, // UART5_BASE
+    0x40011400  // USART6
+  };
+  static USARTMin * regs = (USARTMin*)regsAddr[SERIAL_PORT - 1];
+#endif
+
+static void TXBegin() {
+  #if !WITHIN(SERIAL_PORT, 1, 6)
+    #warning "Using POSTMORTEM_DEBUGGING requires a physical U(S)ART hardware in case of severe error."
+    #warning "Disabling the severe error reporting feature currently because the used serial port is not a HW port."
+  #else
+    // This is common between STM32F1/STM32F2 and STM32F4
+    const int nvicUART[] = { /* NVIC_USART1 */ 37, /* NVIC_USART2 */ 38, /* NVIC_USART3 */ 39, /* NVIC_UART4 */ 52, /* NVIC_UART5 */ 53, /* NVIC_USART6 */ 71 };
+    int nvicIndex = nvicUART[SERIAL_PORT - 1];
+
+    struct NVICMin {
+      volatile uint32_t ISER[32];
+      volatile uint32_t ICER[32];
+    };
+
+    NVICMin *nvicBase = (NVICMin*)0xE000E100;
+    SBI32(nvicBase->ICER[nvicIndex >> 5], nvicIndex & 0x1F);
+
+    // We NEED memory barriers to ensure Interrupts are actually disabled!
+    // ( https://dzone.com/articles/nvic-disabling-interrupts-on-arm-cortex-m-and-the )
+    dsb();
+    isb();
+
+    // Example for USART1 disable:  (RCC->APB2ENR &= ~(RCC_APB2ENR_USART1EN))
+    // Too difficult to reimplement here, let's query the STM32duino macro here
+    #if SERIAL_PORT == 1
+      __HAL_RCC_USART1_CLK_DISABLE();
+      __HAL_RCC_USART1_CLK_ENABLE();
+    #elif SERIAL_PORT == 2
+      __HAL_RCC_USART2_CLK_DISABLE();
+      __HAL_RCC_USART2_CLK_ENABLE();
+    #elif SERIAL_PORT == 3
+      __HAL_RCC_USART3_CLK_DISABLE();
+      __HAL_RCC_USART3_CLK_ENABLE();
+    #elif SERIAL_PORT == 4
+      __HAL_RCC_UART4_CLK_DISABLE(); // BEWARE: UART4 and not USART4 here
+      __HAL_RCC_UART4_CLK_ENABLE();
+    #elif SERIAL_PORT == 5
+      __HAL_RCC_UART5_CLK_DISABLE(); // BEWARE: UART5 and not USART5 here
+      __HAL_RCC_UART5_CLK_ENABLE();
+    #elif SERIAL_PORT == 6
+      __HAL_RCC_USART6_CLK_DISABLE();
+      __HAL_RCC_USART6_CLK_ENABLE();
+    #endif
+
+    uint32_t brr = regs->BRR;
+    regs->CR1 = 0; // Reset the USART
+    regs->CR2 = 0; // 1 stop bit
+
+    // If we don't touch the BRR (baudrate register), we don't need to recompute.
+    regs->BRR = brr;
+
+    regs->CR1 = _BV(3) | _BV(13); // 8 bits, no parity, 1 stop bit (TE | UE)
+  #endif
+}
+
+// A SW memory barrier, to ensure GCC does not overoptimize loops
+#define sw_barrier() __asm__ volatile("": : :"memory");
+static void TX(char c) {
+  #if WITHIN(SERIAL_PORT, 1, 6)
+    constexpr uint32_t usart_sr_txe = _BV(7);
+    while (!(regs->SR & usart_sr_txe)) {
+      TERN_(USE_WATCHDOG, HAL_watchdog_refresh());
+      sw_barrier();
+    }
+    regs->DR = c;
+  #else
+    // Let's hope a mystical guru will fix this, one day by writting interrupt-free USB CDC ACM code (or, at least, by polling the registers since interrupt will be queued but will never trigger)
+    // For now, it's completely lost to oblivion.
+  #endif
+}
+
+void install_min_serial() {
+  HAL_min_serial_init = &TXBegin;
+  HAL_min_serial_out = &TX;
+}
+
+#if DISABLED(DYNAMIC_VECTORTABLE) && DISABLED(STM32F0xx) // Cortex M0 can't jump to a symbol that's too far from the current function, so we work around this in exception_arm.cpp
+extern "C" {
+  __attribute__((naked)) void JumpHandler_ASM() {
+    __asm__ __volatile__ (
+      "b CommonHandler_ASM\n"
+    );
+  }
+  void __attribute__((naked, alias("JumpHandler_ASM"), nothrow)) HardFault_Handler();
+  void __attribute__((naked, alias("JumpHandler_ASM"), nothrow)) BusFault_Handler();
+  void __attribute__((naked, alias("JumpHandler_ASM"), nothrow)) UsageFault_Handler();
+  void __attribute__((naked, alias("JumpHandler_ASM"), nothrow)) MemManage_Handler();
+  void __attribute__((naked, alias("JumpHandler_ASM"), nothrow)) NMI_Handler();
+}
+#endif
+
+#endif // POSTMORTEM_DEBUGGING
+#endif // ARDUINO_ARCH_STM32
@@ -193,7 +193,7 @@ static SPISettings spiConfig;
   *
   * @details Uses DMA
   */
-  void spiRead(uint8_t* buf, uint16_t nbyte) {
+  void spiRead(uint8_t *buf, uint16_t nbyte) {
    if (nbyte == 0) return;
    memset(buf, 0xFF, nbyte);
    SPI.transfer(buf, nbyte);
@@ -218,7 +218,7 @@ static SPISettings spiConfig;
   *
   * @details Use DMA
   */
-  void spiSendBlock(uint8_t token, const uint8_t* buf) {
+  void spiSendBlock(uint8_t token, const uint8_t *buf) {
    uint8_t rxBuf[512];
    SPI.transfer(token);
    SPI.transfer((uint8_t*)buf, &rxBuf, 512);
@@ -19,7 +19,7 @@
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */
-#if defined(ARDUINO_ARCH_STM32) && !defined(STM32GENERIC)
+#if defined(ARDUINO_ARCH_STM32) && !defined(STM32GENERIC) && !defined(STM32H7xx)

 #include "MarlinSPI.h"

@@ -28,7 +28,6 @@
 #ifndef USART4
  #define USART4 UART4
 #endif
-
 #ifndef USART5
  #define USART5 UART5
 #endif
@@ -38,22 +37,38 @@
  MSerialT MSerial ## ser_num (true, USART ## ser_num, &_rx_complete_irq_ ## ser_num); \
  void _rx_complete_irq_ ## ser_num (serial_t * obj) { MSerial ## ser_num ._rx_complete_irq(obj); }

-#define DECLARE_SERIAL_PORT_EXP(ser_num) DECLARE_SERIAL_PORT(ser_num)
-
-#if defined(SERIAL_PORT) && SERIAL_PORT >= 0
-  DECLARE_SERIAL_PORT_EXP(SERIAL_PORT)
+#if USING_HW_SERIAL1
+  DECLARE_SERIAL_PORT(1)
 #endif
-
-#if defined(SERIAL_PORT_2) && SERIAL_PORT_2 >= 0
-  DECLARE_SERIAL_PORT_EXP(SERIAL_PORT_2)
+#if USING_HW_SERIAL2
+  DECLARE_SERIAL_PORT(2)
 #endif
-
-#if defined(MMU2_SERIAL_PORT) && MMU2_SERIAL_PORT >= 0
-  DECLARE_SERIAL_PORT_EXP(MMU2_SERIAL_PORT)
+#if USING_HW_SERIAL3
+  DECLARE_SERIAL_PORT(3)
 #endif
-
-#if defined(LCD_SERIAL_PORT) && LCD_SERIAL_PORT >= 0
-  DECLARE_SERIAL_PORT_EXP(LCD_SERIAL_PORT)
+#if USING_HW_SERIAL4
+  DECLARE_SERIAL_PORT(4)
+#endif
+#if USING_HW_SERIAL5
+  DECLARE_SERIAL_PORT(5)
+#endif
+#if USING_HW_SERIAL6
+  DECLARE_SERIAL_PORT(6)
+#endif
+#if USING_HW_SERIAL7
+  DECLARE_SERIAL_PORT(7)
+#endif
+#if USING_HW_SERIAL8
+  DECLARE_SERIAL_PORT(8)
+#endif
+#if USING_HW_SERIAL9
+  DECLARE_SERIAL_PORT(9)
+#endif
+#if USING_HW_SERIAL10
+  DECLARE_SERIAL_PORT(10)
+#endif
+#if USING_HW_SERIALLP1
+  DECLARE_SERIAL_PORT(LP1)
 #endif

 void MarlinSerial::begin(unsigned long baud, uint8_t config) {
@@ -29,20 +29,20 @@
 typedef void (*usart_rx_callback_t)(serial_t * obj);

 struct MarlinSerial : public HardwareSerial {
-  MarlinSerial(void* peripheral, usart_rx_callback_t rx_callback) :
+  MarlinSerial(void *peripheral, usart_rx_callback_t rx_callback) :
      HardwareSerial(peripheral), _rx_callback(rx_callback)
  { }

  void begin(unsigned long baud, uint8_t config);
  inline void begin(unsigned long baud) { begin(baud, SERIAL_8N1); }

-  void _rx_complete_irq(serial_t* obj);
+  void _rx_complete_irq(serial_t *obj);

 protected:
  usart_rx_callback_t _rx_callback;
 };

-typedef Serial0Type<MarlinSerial> MSerialT;
+typedef Serial1Class<MarlinSerial> MSerialT;
 extern MSerialT MSerial1;
 extern MSerialT MSerial2;
 extern MSerialT MSerial3;
@@ -36,9 +36,10 @@

  // use USB drivers

-  extern "C" { int8_t SD_MSC_Read(uint8_t lun, uint8_t *buf, uint32_t blk_addr, uint16_t blk_len);
-               int8_t SD_MSC_Write(uint8_t lun, uint8_t *buf, uint32_t blk_addr, uint16_t blk_len);
-               extern SD_HandleTypeDef hsd;
+  extern "C" {
+    int8_t SD_MSC_Read(uint8_t lun, uint8_t *buf, uint32_t blk_addr, uint16_t blk_len);
+    int8_t SD_MSC_Write(uint8_t lun, uint8_t *buf, uint32_t blk_addr, uint16_t blk_len);
+    extern SD_HandleTypeDef hsd;
  }

  bool SDIO_Init() {
@@ -75,7 +76,18 @@
    #error "ERROR - Only STM32F103xE, STM32F103xG, STM32F4xx or STM32F7xx CPUs supported"
  #endif

+  // Fixed
+  #define SDIO_D0_PIN   PC8
+  #define SDIO_D1_PIN   PC9
+  #define SDIO_D2_PIN   PC10
+  #define SDIO_D3_PIN   PC11
+  #define SDIO_CK_PIN   PC12
+  #define SDIO_CMD_PIN  PD2
+
  SD_HandleTypeDef hsd;  // create SDIO structure
+  // F4 supports one DMA for RX and another for TX, but Marlin will never
+  // do read and write at same time, so we use the same DMA for both.
+  DMA_HandleTypeDef hdma_sdio;

  /*
    SDIO_INIT_CLK_DIV is 118
@@ -96,12 +108,12 @@

  // Target Clock, configurable. Default is 18MHz, from STM32F1
  #ifndef SDIO_CLOCK
-    #define SDIO_CLOCK                         18000000       /* 18 MHz */
+    #define SDIO_CLOCK 18000000 // 18 MHz
  #endif

  // SDIO retries, configurable. Default is 3, from STM32F1
  #ifndef SDIO_READ_RETRIES
-    #define SDIO_READ_RETRIES                  3
+    #define SDIO_READ_RETRIES 3
  #endif

  // SDIO Max Clock (naming from STM Manual, don't change)
@@ -120,24 +132,21 @@
  }

  void go_to_transfer_speed() {
-    SD_InitTypeDef Init;
-
    /* Default SDIO peripheral configuration for SD card initialization */
-    Init.ClockEdge           = hsd.Init.ClockEdge;
-    Init.ClockBypass         = hsd.Init.ClockBypass;
-    Init.ClockPowerSave      = hsd.Init.ClockPowerSave;
-    Init.BusWide             = hsd.Init.BusWide;
-    Init.HardwareFlowControl = hsd.Init.HardwareFlowControl;
-    Init.ClockDiv            = clock_to_divider(SDIO_CLOCK);
+    hsd.Init.ClockEdge           = hsd.Init.ClockEdge;
+    hsd.Init.ClockBypass         = hsd.Init.ClockBypass;
+    hsd.Init.ClockPowerSave      = hsd.Init.ClockPowerSave;
+    hsd.Init.BusWide             = hsd.Init.BusWide;
+    hsd.Init.HardwareFlowControl = hsd.Init.HardwareFlowControl;
+    hsd.Init.ClockDiv            = clock_to_divider(SDIO_CLOCK);

    /* Initialize SDIO peripheral interface with default configuration */
-    SDIO_Init(hsd.Instance, Init);
+    SDIO_Init(hsd.Instance, hsd.Init);
  }

  void SD_LowLevel_Init(void) {
    uint32_t tempreg;

-    __HAL_RCC_SDIO_CLK_ENABLE();
    __HAL_RCC_GPIOC_CLK_ENABLE(); //enable GPIO clocks
    __HAL_RCC_GPIOD_CLK_ENABLE(); //enable GPIO clocks

@@ -163,11 +172,45 @@
    GPIO_InitStruct.Pin = GPIO_PIN_2;
    HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);

-    #if DISABLED(STM32F1xx)
-      // TODO: use __HAL_RCC_SDIO_RELEASE_RESET() and __HAL_RCC_SDIO_CLK_ENABLE();
-      RCC->APB2RSTR &= ~RCC_APB2RSTR_SDIORST_Msk;  // take SDIO out of reset
-      RCC->APB2ENR  |=  RCC_APB2RSTR_SDIORST_Msk;  // enable SDIO clock
-      // Enable the DMA2 Clock
+    // Setup DMA
+    #if defined(STM32F1xx)
+      hdma_sdio.Init.Mode = DMA_NORMAL;
+      hdma_sdio.Instance = DMA2_Channel4;
+      HAL_NVIC_EnableIRQ(DMA2_Channel4_5_IRQn);
+    #elif defined(STM32F4xx)
+      hdma_sdio.Init.Mode = DMA_PFCTRL;
+      hdma_sdio.Instance = DMA2_Stream3;
+      hdma_sdio.Init.Channel = DMA_CHANNEL_4;
+      hdma_sdio.Init.FIFOMode = DMA_FIFOMODE_ENABLE;
+      hdma_sdio.Init.FIFOThreshold = DMA_FIFO_THRESHOLD_FULL;
+      hdma_sdio.Init.MemBurst = DMA_MBURST_INC4;
+      hdma_sdio.Init.PeriphBurst = DMA_PBURST_INC4;
+      HAL_NVIC_EnableIRQ(DMA2_Stream3_IRQn);
+    #endif
+    HAL_NVIC_EnableIRQ(SDIO_IRQn);
+    hdma_sdio.Init.PeriphInc = DMA_PINC_DISABLE;
+    hdma_sdio.Init.MemInc = DMA_MINC_ENABLE;
+    hdma_sdio.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD;
+    hdma_sdio.Init.MemDataAlignment = DMA_MDATAALIGN_WORD;
+    hdma_sdio.Init.Priority = DMA_PRIORITY_LOW;
+    __HAL_LINKDMA(&hsd, hdmarx, hdma_sdio);
+    __HAL_LINKDMA(&hsd, hdmatx, hdma_sdio);
+
+    #if defined(STM32F1xx)
+      __HAL_RCC_SDIO_CLK_ENABLE();
+      __HAL_RCC_DMA2_CLK_ENABLE();
+    #else
+      __HAL_RCC_SDIO_FORCE_RESET();
+      delay(2);
+      __HAL_RCC_SDIO_RELEASE_RESET();
+      delay(2);
+      __HAL_RCC_SDIO_CLK_ENABLE();
+
+      __HAL_RCC_DMA2_FORCE_RESET();
+      delay(2);
+      __HAL_RCC_DMA2_RELEASE_RESET();
+      delay(2);
+      __HAL_RCC_DMA2_CLK_ENABLE();
    #endif

    //Initialize the SDIO (with initial <400Khz Clock)
@@ -179,6 +222,7 @@

    // Power up the SDIO
    SDIO_PowerState_ON(SDIO);
+    hsd.Instance = SDIO;
  }

  void HAL_SD_MspInit(SD_HandleTypeDef *hsd) { // application specific init
@@ -222,107 +266,81 @@
          if (!status) break;
          if (!--retry_Cnt) return false;   // return failing status if retries are exhausted
        }
+        go_to_transfer_speed();
      }
    #endif

    return true;
  }
-  /*
-  void init_SDIO_pins(void) {
-    GPIO_InitTypeDef GPIO_InitStruct = {0};

-    // SDIO GPIO Configuration
-    // PC8     ------> SDIO_D0
-    // PC12    ------> SDIO_CK
-    // PD2     ------> SDIO_CMD
+  static bool SDIO_ReadWriteBlock_DMA(uint32_t block, const uint8_t *src, uint8_t *dst) {
+    if (HAL_SD_GetCardState(&hsd) != HAL_SD_CARD_TRANSFER) return false;

-    GPIO_InitStruct.Pin = GPIO_PIN_8;
-    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
-    GPIO_InitStruct.Pull = GPIO_NOPULL;
-    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
-    GPIO_InitStruct.Alternate = GPIO_AF12_SDIO;
-    HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);
+    TERN_(USE_WATCHDOG, HAL_watchdog_refresh());

-    GPIO_InitStruct.Pin = GPIO_PIN_12;
-    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
-    GPIO_InitStruct.Pull = GPIO_NOPULL;
-    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
-    GPIO_InitStruct.Alternate = GPIO_AF12_SDIO;
-    HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);
-
-    GPIO_InitStruct.Pin = GPIO_PIN_2;
-    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
-    GPIO_InitStruct.Pull = GPIO_NOPULL;
-    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
-    GPIO_InitStruct.Alternate = GPIO_AF12_SDIO;
-    HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);
-  }
-  */
-  //bool SDIO_init() { return (bool) (SD_SDIO_Init() ? 1 : 0);}
-  //bool SDIO_Init_C() { return (bool) (SD_SDIO_Init() ? 1 : 0);}
-
-  bool SDIO_ReadBlock(uint32_t block, uint8_t *dst) {
-    hsd.Instance = SDIO;
-    uint8_t retryCnt = SDIO_READ_RETRIES;
-
-    bool status;
-    for (;;) {
-      TERN_(USE_WATCHDOG, HAL_watchdog_refresh());
-      status = (bool) HAL_SD_ReadBlocks(&hsd, (uint8_t*)dst, block, 1, 1000);  // read one 512 byte block with 500mS timeout
-      status |= (bool) HAL_SD_GetCardState(&hsd);     // make sure all is OK
-      if (!status) break;       // return passing status
-      if (!--retryCnt) break;   // return failing status if retries are exhausted
+    HAL_StatusTypeDef ret;
+    if (src) {
+      hdma_sdio.Init.Direction = DMA_MEMORY_TO_PERIPH;
+      HAL_DMA_Init(&hdma_sdio);
+      ret = HAL_SD_WriteBlocks_DMA(&hsd, (uint8_t *)src, block, 1);
+    }
+    else {
+      hdma_sdio.Init.Direction = DMA_PERIPH_TO_MEMORY;
+      HAL_DMA_Init(&hdma_sdio);
+      ret = HAL_SD_ReadBlocks_DMA(&hsd, (uint8_t *)dst, block, 1);
    }
-    return status;

-    /*
-    return (bool) ((status_read | status_card) ? 1 : 0);
-
-    if (SDIO_GetCardState() != SDIO_CARD_TRANSFER) return false;
-    if (blockAddress >= SdCard.LogBlockNbr) return false;
-    if ((0x03 & (uint32_t)data)) return false; // misaligned data
-
-    if (SdCard.CardType != CARD_SDHC_SDXC) { blockAddress *= 512U; }
-
-    if (!SDIO_CmdReadSingleBlock(blockAddress)) {
-      SDIO_CLEAR_FLAG(SDIO_ICR_CMD_FLAGS);
-      dma_disable(SDIO_DMA_DEV, SDIO_DMA_CHANNEL);
+    if (ret != HAL_OK) {
+      HAL_DMA_Abort_IT(&hdma_sdio);
+      HAL_DMA_DeInit(&hdma_sdio);
      return false;
    }

-    while (!SDIO_GET_FLAG(SDIO_STA_DATAEND | SDIO_STA_TRX_ERROR_FLAGS)) {}
-
-    dma_disable(SDIO_DMA_DEV, SDIO_DMA_CHANNEL);
-
-    if (SDIO->STA & SDIO_STA_RXDAVL) {
-      while (SDIO->STA & SDIO_STA_RXDAVL) (void)SDIO->FIFO;
-      SDIO_CLEAR_FLAG(SDIO_ICR_CMD_FLAGS | SDIO_ICR_DATA_FLAGS);
-      return false;
+    millis_t timeout = millis() + 500;
+    // Wait the transfer
+    while (hsd.State != HAL_SD_STATE_READY) {
+      if (ELAPSED(millis(), timeout)) {
+        HAL_DMA_Abort_IT(&hdma_sdio);
+        HAL_DMA_DeInit(&hdma_sdio);
+        return false;
+      }
    }

-    if (SDIO_GET_FLAG(SDIO_STA_TRX_ERROR_FLAGS)) {
-      SDIO_CLEAR_FLAG(SDIO_ICR_CMD_FLAGS | SDIO_ICR_DATA_FLAGS);
-      return false;
-    }
-    SDIO_CLEAR_FLAG(SDIO_ICR_CMD_FLAGS | SDIO_ICR_DATA_FLAGS);
-    */
+    while (__HAL_DMA_GET_FLAG(&hdma_sdio, __HAL_DMA_GET_TC_FLAG_INDEX(&hdma_sdio)) != 0
+        || __HAL_DMA_GET_FLAG(&hdma_sdio, __HAL_DMA_GET_TE_FLAG_INDEX(&hdma_sdio)) != 0) { /* nada */ }
+
+    HAL_DMA_Abort_IT(&hdma_sdio);
+    HAL_DMA_DeInit(&hdma_sdio);
+
+    timeout = millis() + 500;
+    while (HAL_SD_GetCardState(&hsd) != HAL_SD_CARD_TRANSFER) if (ELAPSED(millis(), timeout)) return false;

    return true;
  }

-  bool SDIO_WriteBlock(uint32_t block, const uint8_t *src) {
-    hsd.Instance = SDIO;
-    uint8_t retryCnt = SDIO_READ_RETRIES;
-    bool status;
-    for (;;) {
-      status = (bool) HAL_SD_WriteBlocks(&hsd, (uint8_t*)src, block, 1, 500);  // write one 512 byte block with 500mS timeout
-      status |= (bool) HAL_SD_GetCardState(&hsd);     // make sure all is OK
-      if (!status) break;       // return passing status
-      if (!--retryCnt) break;   // return failing status if retries are exhausted
-    }
-    return status;
+  bool SDIO_ReadBlock(uint32_t block, uint8_t *dst) {
+    uint8_t retries = SDIO_READ_RETRIES;
+    while (retries--) if (SDIO_ReadWriteBlock_DMA(block, NULL, dst)) return true;
+    return false;
  }

+  bool SDIO_WriteBlock(uint32_t block, const uint8_t *src) {
+    uint8_t retries = SDIO_READ_RETRIES;
+    while (retries--) if (SDIO_ReadWriteBlock_DMA(block, src, NULL)) return true;
+    return false;
+  }
+
+  #if defined(STM32F1xx)
+    #define DMA_IRQ_HANDLER DMA2_Channel4_5_IRQHandler
+  #elif defined(STM32F4xx)
+    #define DMA_IRQ_HANDLER DMA2_Stream3_IRQHandler
+  #else
+    #error "Unknown STM32 architecture."
+  #endif
+
+  extern "C" void SDIO_IRQHandler(void) { HAL_SD_IRQHandler(&hsd); }
+  extern "C" void DMA_IRQ_HANDLER(void) { HAL_DMA_IRQHandler(&hdma_sdio); }
+
 #endif // !USBD_USE_CDC_COMPOSITE
 #endif // SDIO_SUPPORT
 #endif // ARDUINO_ARCH_STM32 && !STM32GENERIC
@@ -48,7 +48,7 @@
  #include "stm32_def.h"

  #define DEBUG_OUT ENABLED(EEPROM_CHITCHAT)
-  #include "src/core/debug_out.h"
+  #include "../../core/debug_out.h"

  #ifndef MARLIN_EEPROM_SIZE
    #define MARLIN_EEPROM_SIZE    0x1000 // 4KB
@@ -43,25 +43,22 @@ bool PersistentStore::access_start()  { eeprom_init(); return true; }
 bool PersistentStore::access_finish() { return true; }

 bool PersistentStore::write_data(int &pos, const uint8_t *value, size_t size, uint16_t *crc) {
+  uint16_t written = 0;
  while (size--) {
    uint8_t v = *value;
-
-    // EEPROM has only ~100,000 write cycles,
-    // so only write bytes that have changed!
    uint8_t * const p = (uint8_t * const)pos;
-    if (v != eeprom_read_byte(p)) {
+    if (v != eeprom_read_byte(p)) { // EEPROM has only ~100,000 write cycles, so only write bytes that have changed!
      eeprom_write_byte(p, v);
+      if (++written & 0x7F) delay(2); else safe_delay(2); // Avoid triggering watchdog during long EEPROM writes
      if (eeprom_read_byte(p) != v) {
        SERIAL_ECHO_MSG(STR_ERR_EEPROM_WRITE);
        return true;
      }
    }
-
    crc16(crc, &v, 1);
    pos++;
    value++;
-  };
-
+  }
  return false;
 }

@@ -24,3 +24,9 @@
 #if defined(USBD_USE_CDC_MSC) && DISABLED(NO_SD_HOST_DRIVE)
  #define HAS_SD_HOST_DRIVE 1
 #endif
+
+// Fix F_CPU not being a compile-time constant in STSTM32 framework
+#ifdef BOARD_F_CPU
+  #undef F_CPU
+  #define F_CPU BOARD_F_CPU
+#endif
@@ -47,11 +47,11 @@
 #endif

 #if ENABLED(SERIAL_STATS_MAX_RX_QUEUED)
-  #error "SERIAL_STATS_MAX_RX_QUEUED is not supported on this platform."
+  #error "SERIAL_STATS_MAX_RX_QUEUED is not supported on STM32."
 #elif ENABLED(SERIAL_STATS_DROPPED_RX)
-  #error "SERIAL_STATS_DROPPED_RX is not supported on this platform."
+  #error "SERIAL_STATS_DROPPED_RX is not supported on STM32."
 #endif

-#if ANY(TFT_COLOR_UI, TFT_LVGL_UI, TFT_CLASSIC_UI) && NOT_TARGET(STM32F4xx, STM32F1xx)
-  #error "TFT_COLOR_UI, TFT_LVGL_UI and TFT_CLASSIC_UI are currently only supported on STM32F4 and STM32F1 hardware."
+#if ANY(TFT_COLOR_UI, TFT_LVGL_UI, TFT_CLASSIC_UI) && NOT_TARGET(STM32H7xx, STM32F4xx, STM32F1xx)
+  #error "TFT_COLOR_UI, TFT_LVGL_UI and TFT_CLASSIC_UI are currently only supported on STM32H7, STM32F4 and STM32F1 hardware."
 #endif
@@ -30,54 +30,66 @@

 class Sd2CardUSBMscHandler : public USBMscHandler {
 public:
+  DiskIODriver* diskIODriver() {
+    #if ENABLED(MULTI_VOLUME)
+      #if SHARED_VOLUME_IS(SD_ONBOARD)
+        return &card.media_sd_spi;
+      #elif SHARED_VOLUME_IS(USB_FLASH_DRIVE)
+        return &card.media_usbFlashDrive;
+      #endif
+    #else
+      return card.diskIODriver();
+    #endif
+  }
+
  bool GetCapacity(uint32_t *pBlockNum, uint16_t *pBlockSize) {
-    *pBlockNum = card.getSd2Card().cardSize();
+    *pBlockNum = diskIODriver()->cardSize();
    *pBlockSize = BLOCK_SIZE;
    return true;
  }

  bool Write(uint8_t *pBuf, uint32_t blkAddr, uint16_t blkLen) {
-    auto sd2card = card.getSd2Card();
+    auto sd2card = diskIODriver();
    // single block
    if (blkLen == 1) {
      watchdog_refresh();
-      sd2card.writeBlock(blkAddr, pBuf);
+      sd2card->writeBlock(blkAddr, pBuf);
      return true;
    }

    // multi block optmization
-    sd2card.writeStart(blkAddr, blkLen);
+    sd2card->writeStart(blkAddr, blkLen);
    while (blkLen--) {
      watchdog_refresh();
-      sd2card.writeData(pBuf);
+      sd2card->writeData(pBuf);
      pBuf += BLOCK_SIZE;
    }
-    sd2card.writeStop();
+    sd2card->writeStop();
    return true;
  }

  bool Read(uint8_t *pBuf, uint32_t blkAddr, uint16_t blkLen) {
-    auto sd2card = card.getSd2Card();
+    auto sd2card = diskIODriver();
    // single block
    if (blkLen == 1) {
      watchdog_refresh();
-      sd2card.readBlock(blkAddr, pBuf);
+      sd2card->readBlock(blkAddr, pBuf);
      return true;
    }

    // multi block optmization
-    sd2card.readStart(blkAddr);
+    sd2card->readStart(blkAddr);
    while (blkLen--) {
      watchdog_refresh();
-      sd2card.readData(pBuf);
+      sd2card->readData(pBuf);
      pBuf += BLOCK_SIZE;
    }
-    sd2card.readStop();
+    sd2card->readStop();
    return true;
  }

  bool IsReady() {
-    return card.isMounted();
+    return diskIODriver()->isReady();
  }
 };

@@ -105,8 +117,8 @@ USBMscHandler *pSingleMscHandler = &usbMscHandler;
 void MSC_SD_init() {
  USBDevice.end();
  delay(200);
-  USBDevice.begin();
  USBDevice.registerMscHandlers(1, &pSingleMscHandler, Marlin_STORAGE_Inquirydata);
+  USBDevice.begin();
 }

 #endif // __STM32F1__ && HAS_SD_HOST_DRIVE
@@ -0,0 +1,202 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#if defined(ARDUINO_ARCH_STM32) && !defined(STM32GENERIC)
+
+#include "../../../inc/MarlinConfig.h"
+
+#if ENABLED(TFT_TOUCH_DEVICE_GT911)
+
+#include "gt911.h"
+#include "pinconfig.h"
+
+SW_IIC::SW_IIC(uint16_t sda, uint16_t scl) {
+  scl_pin = scl;
+  sda_pin = sda;
+}
+
+// Software I2C hardware io init
+void SW_IIC::init() {
+  OUT_WRITE(scl_pin, HIGH);
+  OUT_WRITE(sda_pin, HIGH);
+}
+
+// Software I2C start signal
+void SW_IIC::start() {
+  write_sda(HIGH); // SDA = 1
+  write_scl(HIGH); // SCL = 1
+  iic_delay(2);
+  write_sda(LOW); // SDA = 0
+  iic_delay(1);
+  write_scl(LOW); // SCL = 0  // keep SCL low, avoid false stop caused by level jump caused by SDA switching IN/OUT
+}
+
+// Software I2C stop signal
+void SW_IIC::stop() {
+  write_scl(LOW); // SCL = 0
+  iic_delay(2);
+  write_sda(LOW); // SDA = 0
+  iic_delay(2);
+  write_scl(HIGH); // SCL = 1
+  iic_delay(2);
+  write_sda(HIGH); // SDA = 1
+}
+
+// Software I2C sends ACK or NACK signal
+void SW_IIC::send_ack(bool ack) {
+  write_sda(ack ? LOW : HIGH); // SDA = !ack
+  iic_delay(2);
+  write_scl(HIGH); // SCL = 1
+  iic_delay(2);
+  write_scl(LOW); // SCL = 0
+}
+
+// Software I2C read ACK or NACK signal
+bool SW_IIC::read_ack() {
+  bool error = 0;
+  set_sda_in();
+
+  iic_delay(2);
+
+  write_scl(HIGH); // SCL = 1
+  error = read_sda();
+
+  iic_delay(2);
+
+  write_scl(LOW);  // SCL = 0
+
+  set_sda_out();
+  return error;
+}
+
+void SW_IIC::send_byte(uint8_t txd) {
+  LOOP_L_N(i, 8) {
+    write_sda(txd & 0x80); // write data bit
+    txd <<= 1;
+    iic_delay(1);
+    write_scl(HIGH); // SCL = 1
+    iic_delay(2);
+    write_scl(LOW); // SCL = 0
+    iic_delay(1);
+  }
+
+  read_ack();  // wait ack
+}
+
+uint8_t SW_IIC::read_byte(bool ack) {
+  uint8_t data = 0;
+
+  set_sda_in();
+  LOOP_L_N(i, 8) {
+    write_scl(HIGH); // SCL = 1
+    iic_delay(1);
+    data <<= 1;
+    if (read_sda()) data++;
+    write_scl(LOW); // SCL = 0
+    iic_delay(2);
+  }
+  set_sda_out();
+
+  send_ack(ack);
+
+  return data;
+}
+
+GT911_REG_MAP GT911::reg;
+SW_IIC GT911::sw_iic = SW_IIC(GT911_SW_I2C_SDA_PIN, GT911_SW_I2C_SCL_PIN);
+
+void GT911::write_reg(uint16_t reg, uint8_t reg_len, uint8_t* w_data, uint8_t w_len) {
+  sw_iic.start();
+  sw_iic.send_byte(gt911_slave_address);  // Set IIC Slave address
+  LOOP_L_N(i, reg_len) {  // Set reg address
+    uint8_t r = (reg >> (8 * (reg_len - 1 - i))) & 0xFF;
+    sw_iic.send_byte(r);
+  }
+
+  LOOP_L_N(i, w_len) {  // Write data to reg
+    sw_iic.send_byte(w_data[i]);
+  }
+  sw_iic.stop();
+}
+
+void GT911::read_reg(uint16_t reg, uint8_t reg_len, uint8_t* r_data, uint8_t r_len) {
+  sw_iic.start();
+  sw_iic.send_byte(gt911_slave_address);  // Set IIC Slave address
+  LOOP_L_N(i, reg_len) {  // Set reg address
+    uint8_t r = (reg >> (8 * (reg_len - 1 - i))) & 0xFF;
+    sw_iic.send_byte(r);
+  }
+
+  sw_iic.start();
+  sw_iic.send_byte(gt911_slave_address + 1);  // Set read mode
+
+  LOOP_L_N(i, r_len) {
+    r_data[i] = sw_iic.read_byte(1);  // Read data from reg
+  }
+  sw_iic.stop();
+}
+
+void GT911::Init() {
+  OUT_WRITE(GT911_RST_PIN, LOW);
+  OUT_WRITE(GT911_INT_PIN, LOW);
+  delay(20);
+  WRITE(GT911_RST_PIN, HIGH);
+  SET_INPUT(GT911_INT_PIN);
+
+  sw_iic.init();
+
+  uint8_t clear_reg = 0x0000;
+  write_reg(0x814E, 2, &clear_reg, 2); // Reset to 0 for start
+}
+
+bool GT911::getFirstTouchPoint(int16_t *x, int16_t *y) {
+  read_reg(0x814E, 2, &reg.REG.status, 1);
+
+  if (reg.REG.status & 0x80) {
+    uint8_t clear_reg = 0x00;
+    write_reg(0x814E, 2, &clear_reg, 1); // Reset to 0 for start
+    read_reg(0x8150, 2, reg.map + 2, 8 * (reg.REG.status & 0x0F));
+
+    // First touch point
+    *x = ((reg.REG.point[0].xh & 0x0F) << 8) | reg.REG.point[0].xl;
+    *y = ((reg.REG.point[0].yh & 0x0F) << 8) | reg.REG.point[0].yl;
+    return true;
+  }
+  return false;
+}
+
+bool GT911::getPoint(int16_t *x, int16_t *y) {
+  static bool touched = 0;
+  static int16_t read_x = 0, read_y = 0;
+  static millis_t next_time = 0;
+
+  if (ELAPSED(millis(), next_time)) {
+    touched = getFirstTouchPoint(&read_x, &read_y);
+    next_time = millis() + 20;
+  }
+
+  *x = read_x;
+  *y = read_y;
+  return touched;
+}
+
+#endif // TFT_TOUCH_DEVICE_GT911
+#endif // ARDUINO_ARCH_STM32 && !STM32GENERIC
@@ -0,0 +1,120 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#pragma once
+
+#include "../../../inc/MarlinConfig.h"
+
+#define GT911_SLAVE_ADDRESS   0xBA
+
+#if !PIN_EXISTS(GT911_RST)
+  #error "GT911_RST_PIN is not defined."
+#elif !PIN_EXISTS(GT911_INT)
+  #error "GT911_INT_PIN is not defined."
+#elif !PIN_EXISTS(GT911_SW_I2C_SCL)
+  #error "GT911_SW_I2C_SCL_PIN is not defined."
+#elif !PIN_EXISTS(GT911_SW_I2C_SDA)
+  #error "GT911_SW_I2C_SDA_PIN is not defined."
+#endif
+
+class SW_IIC {
+  private:
+    uint16_t scl_pin;
+    uint16_t sda_pin;
+    void write_scl(bool level)
+    {
+      WRITE(scl_pin, level);
+    }
+    void write_sda(bool level)
+    {
+      WRITE(sda_pin, level);
+    }
+    bool read_sda()
+    {
+      return READ(sda_pin);
+    }
+    void set_sda_out()
+    {
+      SET_OUTPUT(sda_pin);
+    }
+    void set_sda_in()
+    {
+      SET_INPUT_PULLUP(sda_pin);
+    }
+    static void iic_delay(uint8_t t)
+    {
+      delayMicroseconds(t);
+    }
+
+  public:
+    SW_IIC(uint16_t sda, uint16_t scl);
+    // setSCL/SDA have to be called before begin()
+    void setSCL(uint16_t scl)
+    {
+      scl_pin = scl;
+    };
+    void setSDA(uint16_t sda)
+    {
+      sda_pin = sda;
+    };
+    void init();                // Initialize the IO port of IIC
+    void start();               // Send IIC start signal
+    void stop();                // Send IIC stop signal
+    void send_byte(uint8_t txd); // IIC sends a byte
+    uint8_t read_byte(bool ack); // IIC reads a byte
+    void send_ack(bool ack);            // IIC sends ACK or NACK signal
+    bool read_ack();
+};
+
+typedef struct __attribute__((__packed__)) {
+  uint8_t xl;
+  uint8_t xh;
+  uint8_t yl;
+  uint8_t yh;
+  uint8_t sizel;
+  uint8_t sizeh;
+  uint8_t reserved;
+  uint8_t track_id;
+} GT911_POINT;
+
+typedef union __attribute__((__packed__)) {
+  uint8_t map[42];
+  struct {
+    uint8_t status;    // 0x814E
+    uint8_t track_id;  // 0x814F
+
+    GT911_POINT point[5]; // [0]:0x8150 - 0x8157 / [1]:0x8158 - 0x815F / [2]:0x8160 - 0x8167 / [3]:0x8168 - 0x816F / [4]:0x8170 - 0x8177
+ } REG;
+} GT911_REG_MAP;
+
+class GT911 {
+  private:
+    static const uint8_t gt911_slave_address = GT911_SLAVE_ADDRESS;
+    static GT911_REG_MAP reg;
+    static SW_IIC sw_iic;
+    static void write_reg(uint16_t reg, uint8_t reg_len, uint8_t* w_data, uint8_t w_len);
+    static void read_reg(uint16_t reg, uint8_t reg_len, uint8_t* r_data, uint8_t r_len);
+
+  public:
+    static void Init();
+    static bool getFirstTouchPoint(int16_t *x, int16_t *y);
+    static bool getPoint(int16_t *x, int16_t *y);
+};
@@ -0,0 +1,387 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#if defined(ARDUINO_ARCH_STM32) && !defined(STM32GENERIC)
+
+#include "../../../inc/MarlinConfig.h"
+
+#if HAS_LTDC_TFT
+
+#include "tft_ltdc.h"
+#include "pinconfig.h"
+
+#define FRAME_BUFFER_ADDRESS 0XC0000000  // SDRAM address
+
+#define SDRAM_TIMEOUT                            ((uint32_t)0xFFFF)
+#define REFRESH_COUNT                            ((uint32_t)0x02A5)  // SDRAM refresh counter
+
+#define SDRAM_MODEREG_BURST_LENGTH_1             ((uint16_t)0x0000)
+#define SDRAM_MODEREG_BURST_LENGTH_2             ((uint16_t)0x0001)
+#define SDRAM_MODEREG_BURST_LENGTH_4             ((uint16_t)0x0002)
+#define SDRAM_MODEREG_BURST_LENGTH_8             ((uint16_t)0x0004)
+#define SDRAM_MODEREG_BURST_TYPE_SEQUENTIAL      ((uint16_t)0x0000)
+#define SDRAM_MODEREG_BURST_TYPE_INTERLEAVED     ((uint16_t)0x0008)
+#define SDRAM_MODEREG_CAS_LATENCY_2              ((uint16_t)0x0020)
+#define SDRAM_MODEREG_CAS_LATENCY_3              ((uint16_t)0x0030)
+#define SDRAM_MODEREG_OPERATING_MODE_STANDARD    ((uint16_t)0x0000)
+#define SDRAM_MODEREG_WRITEBURST_MODE_PROGRAMMED ((uint16_t)0x0000)
+#define SDRAM_MODEREG_WRITEBURST_MODE_SINGLE     ((uint16_t)0x0200)
+
+void SDRAM_Initialization_Sequence(SDRAM_HandleTypeDef *hsdram, FMC_SDRAM_CommandTypeDef *Command) {
+
+  __IO uint32_t tmpmrd =0;
+  /* Step 1:  Configure a clock configuration enable command */
+  Command->CommandMode = FMC_SDRAM_CMD_CLK_ENABLE;
+  Command->CommandTarget = FMC_SDRAM_CMD_TARGET_BANK1;
+  Command->AutoRefreshNumber = 1;
+  Command->ModeRegisterDefinition = 0;
+  /* Send the command */
+  HAL_SDRAM_SendCommand(hsdram, Command, SDRAM_TIMEOUT);
+
+  /* Step 2: Insert 100 us minimum delay */
+  /* Inserted delay is equal to 1 ms due to systick time base unit (ms) */
+  HAL_Delay(1);
+
+  /* Step 3: Configure a PALL (precharge all) command */
+  Command->CommandMode = FMC_SDRAM_CMD_PALL;
+  Command->CommandTarget = FMC_SDRAM_CMD_TARGET_BANK1;
+  Command->AutoRefreshNumber = 1;
+  Command->ModeRegisterDefinition = 0;
+  /* Send the command */
+  HAL_SDRAM_SendCommand(hsdram, Command, SDRAM_TIMEOUT);
+
+  /* Step 4 : Configure a Auto-Refresh command */
+  Command->CommandMode = FMC_SDRAM_CMD_AUTOREFRESH_MODE;
+  Command->CommandTarget = FMC_SDRAM_CMD_TARGET_BANK1;
+  Command->AutoRefreshNumber = 8;
+  Command->ModeRegisterDefinition = 0;
+  /* Send the command */
+  HAL_SDRAM_SendCommand(hsdram, Command, SDRAM_TIMEOUT);
+
+  /* Step 5: Program the external memory mode register */
+  tmpmrd = (uint32_t)(SDRAM_MODEREG_BURST_LENGTH_1          |
+                      SDRAM_MODEREG_BURST_TYPE_SEQUENTIAL   |
+                      SDRAM_MODEREG_CAS_LATENCY_2           |
+                      SDRAM_MODEREG_OPERATING_MODE_STANDARD |
+                      SDRAM_MODEREG_WRITEBURST_MODE_SINGLE);
+
+  Command->CommandMode = FMC_SDRAM_CMD_LOAD_MODE;
+  Command->CommandTarget = FMC_SDRAM_CMD_TARGET_BANK1;
+  Command->AutoRefreshNumber = 1;
+  Command->ModeRegisterDefinition = tmpmrd;
+  /* Send the command */
+  HAL_SDRAM_SendCommand(hsdram, Command, SDRAM_TIMEOUT);
+
+  /* Step 6: Set the refresh rate counter */
+  /* Set the device refresh rate */
+  HAL_SDRAM_ProgramRefreshRate(hsdram, REFRESH_COUNT);
+}
+
+void SDRAM_Config() {
+
+  __HAL_RCC_SYSCFG_CLK_ENABLE();
+  __HAL_RCC_FMC_CLK_ENABLE();
+
+  SDRAM_HandleTypeDef      hsdram;
+  FMC_SDRAM_TimingTypeDef  SDRAM_Timing;
+  FMC_SDRAM_CommandTypeDef command;
+
+  /* Configure the SDRAM device */
+  hsdram.Instance = FMC_SDRAM_DEVICE;
+  hsdram.Init.SDBank             = FMC_SDRAM_BANK1;
+  hsdram.Init.ColumnBitsNumber   = FMC_SDRAM_COLUMN_BITS_NUM_9;
+  hsdram.Init.RowBitsNumber      = FMC_SDRAM_ROW_BITS_NUM_13;
+  hsdram.Init.MemoryDataWidth    = FMC_SDRAM_MEM_BUS_WIDTH_16;
+  hsdram.Init.InternalBankNumber = FMC_SDRAM_INTERN_BANKS_NUM_4;
+  hsdram.Init.CASLatency         = FMC_SDRAM_CAS_LATENCY_2;
+  hsdram.Init.WriteProtection    = FMC_SDRAM_WRITE_PROTECTION_DISABLE;
+  hsdram.Init.SDClockPeriod      = FMC_SDRAM_CLOCK_PERIOD_2;
+  hsdram.Init.ReadBurst          = FMC_SDRAM_RBURST_ENABLE;
+  hsdram.Init.ReadPipeDelay      = FMC_SDRAM_RPIPE_DELAY_0;
+
+  /* Timing configuration for 100Mhz as SDRAM clock frequency (System clock is up to 200Mhz) */
+  SDRAM_Timing.LoadToActiveDelay    = 2;
+  SDRAM_Timing.ExitSelfRefreshDelay = 8;
+  SDRAM_Timing.SelfRefreshTime      = 6;
+  SDRAM_Timing.RowCycleDelay        = 6;
+  SDRAM_Timing.WriteRecoveryTime    = 2;
+  SDRAM_Timing.RPDelay              = 2;
+  SDRAM_Timing.RCDDelay             = 2;
+
+  /* Initialize the SDRAM controller */
+  if (HAL_SDRAM_Init(&hsdram, &SDRAM_Timing) != HAL_OK)
+  {
+    /* Initialization Error */
+  }
+
+  /* Program the SDRAM external device */
+  SDRAM_Initialization_Sequence(&hsdram, &command);
+}
+
+void LTDC_Config() {
+
+  __HAL_RCC_LTDC_CLK_ENABLE();
+  __HAL_RCC_DMA2D_CLK_ENABLE();
+
+  RCC_PeriphCLKInitTypeDef  PeriphClkInitStruct;
+
+  /* The PLL3R is configured to provide the LTDC PCLK clock */
+  /* PLL3_VCO Input = HSE_VALUE / PLL3M = 25Mhz / 5 = 5 Mhz */
+  /* PLL3_VCO Output = PLL3_VCO Input * PLL3N = 5Mhz * 160 = 800 Mhz */
+  /* PLLLCDCLK = PLL3_VCO Output/PLL3R = 800Mhz / 16 = 50Mhz */
+  /* LTDC clock frequency = PLLLCDCLK = 50 Mhz */
+  PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_LTDC;
+  PeriphClkInitStruct.PLL3.PLL3M = 5;
+  PeriphClkInitStruct.PLL3.PLL3N = 160;
+  PeriphClkInitStruct.PLL3.PLL3FRACN = 0;
+  PeriphClkInitStruct.PLL3.PLL3P = 2;
+  PeriphClkInitStruct.PLL3.PLL3Q = 2;
+  PeriphClkInitStruct.PLL3.PLL3R = (800 / LTDC_LCD_CLK);
+  PeriphClkInitStruct.PLL3.PLL3VCOSEL = RCC_PLL3VCOWIDE;
+  PeriphClkInitStruct.PLL3.PLL3RGE = RCC_PLL3VCIRANGE_2;
+  HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct);
+
+  LTDC_HandleTypeDef hltdc_F;
+  LTDC_LayerCfgTypeDef pLayerCfg;
+
+  /* LTDC Initialization -------------------------------------------------------*/
+
+  /* Polarity configuration */
+  /* Initialize the horizontal synchronization polarity as active low */
+  hltdc_F.Init.HSPolarity = LTDC_HSPOLARITY_AL;
+  /* Initialize the vertical synchronization polarity as active low */
+  hltdc_F.Init.VSPolarity = LTDC_VSPOLARITY_AL;
+  /* Initialize the data enable polarity as active low */
+  hltdc_F.Init.DEPolarity = LTDC_DEPOLARITY_AL;
+  /* Initialize the pixel clock polarity as input pixel clock */
+  hltdc_F.Init.PCPolarity = LTDC_PCPOLARITY_IPC;
+
+  /* Timing configuration */
+  hltdc_F.Init.HorizontalSync = (LTDC_LCD_HSYNC - 1);
+  hltdc_F.Init.VerticalSync = (LTDC_LCD_VSYNC - 1);
+  hltdc_F.Init.AccumulatedHBP = (LTDC_LCD_HSYNC + LTDC_LCD_HBP - 1);
+  hltdc_F.Init.AccumulatedVBP = (LTDC_LCD_VSYNC + LTDC_LCD_VBP - 1);
+  hltdc_F.Init.AccumulatedActiveH = (TFT_HEIGHT + LTDC_LCD_VSYNC + LTDC_LCD_VBP - 1);
+  hltdc_F.Init.AccumulatedActiveW = (TFT_WIDTH + LTDC_LCD_HSYNC + LTDC_LCD_HBP - 1);
+  hltdc_F.Init.TotalHeigh = (TFT_HEIGHT + LTDC_LCD_VSYNC + LTDC_LCD_VBP + LTDC_LCD_VFP - 1);
+  hltdc_F.Init.TotalWidth = (TFT_WIDTH + LTDC_LCD_HSYNC + LTDC_LCD_HBP + LTDC_LCD_HFP - 1);
+
+  /* Configure R,G,B component values for LCD background color : all black background */
+  hltdc_F.Init.Backcolor.Blue = 0;
+  hltdc_F.Init.Backcolor.Green = 0;
+  hltdc_F.Init.Backcolor.Red = 0;
+
+  hltdc_F.Instance = LTDC;
+
+  /* Layer0 Configuration ------------------------------------------------------*/
+
+  /* Windowing configuration */
+  pLayerCfg.WindowX0 = 0;
+  pLayerCfg.WindowX1 = TFT_WIDTH;
+  pLayerCfg.WindowY0 = 0;
+  pLayerCfg.WindowY1 = TFT_HEIGHT;
+
+  /* Pixel Format configuration*/
+  pLayerCfg.PixelFormat = LTDC_PIXEL_FORMAT_RGB565;
+
+  /* Start Address configuration : frame buffer is located at SDRAM memory */
+  pLayerCfg.FBStartAdress = (uint32_t)(FRAME_BUFFER_ADDRESS);
+
+  /* Alpha constant (255 == totally opaque) */
+  pLayerCfg.Alpha = 255;
+
+  /* Default Color configuration (configure A,R,G,B component values) : no background color */
+  pLayerCfg.Alpha0 = 0; /* fully transparent */
+  pLayerCfg.Backcolor.Blue = 0;
+  pLayerCfg.Backcolor.Green = 0;
+  pLayerCfg.Backcolor.Red = 0;
+
+  /* Configure blending factors */
+  pLayerCfg.BlendingFactor1 = LTDC_BLENDING_FACTOR1_CA;
+  pLayerCfg.BlendingFactor2 = LTDC_BLENDING_FACTOR2_CA;
+
+  /* Configure the number of lines and number of pixels per line */
+  pLayerCfg.ImageWidth  = TFT_WIDTH;
+  pLayerCfg.ImageHeight = TFT_HEIGHT;
+
+  /* Configure the LTDC */
+  if (HAL_LTDC_Init(&hltdc_F) != HAL_OK)
+  {
+    /* Initialization Error */
+  }
+
+  /* Configure the Layer*/
+  if (HAL_LTDC_ConfigLayer(&hltdc_F, &pLayerCfg, 0) != HAL_OK)
+  {
+    /* Initialization Error */
+  }
+}
+
+uint16_t TFT_LTDC::x_min = 0;
+uint16_t TFT_LTDC::x_max = 0;
+uint16_t TFT_LTDC::y_min = 0;
+uint16_t TFT_LTDC::y_max = 0;
+uint16_t TFT_LTDC::x_cur = 0;
+uint16_t TFT_LTDC::y_cur = 0;
+uint8_t TFT_LTDC::reg = 0;
+volatile uint16_t* TFT_LTDC::framebuffer = (volatile uint16_t* )FRAME_BUFFER_ADDRESS;
+
+void TFT_LTDC::Init() {
+
+  // SDRAM pins init
+  for (uint16_t i = 0; PinMap_SDRAM[i].pin != NC; i++)
+    pinmap_pinout(PinMap_SDRAM[i].pin, PinMap_SDRAM);
+
+  // SDRAM peripheral config
+  SDRAM_Config();
+
+  // LTDC pins init
+  for (uint16_t i = 0; PinMap_LTDC[i].pin != NC; i++)
+    pinmap_pinout(PinMap_LTDC[i].pin, PinMap_LTDC);
+
+  // LTDC peripheral config
+  LTDC_Config();
+}
+
+uint32_t TFT_LTDC::GetID() {
+  return 0xABAB;
+}
+
+uint32_t TFT_LTDC::ReadID(tft_data_t Reg) {
+  return 0xABAB;
+}
+
+bool TFT_LTDC::isBusy() {
+  return false;
+}
+
+uint16_t TFT_LTDC::ReadPoint(uint16_t x, uint16_t y) {
+  return framebuffer[(TFT_WIDTH * y) + x];
+}
+
+void TFT_LTDC::DrawPoint(uint16_t x, uint16_t y, uint16_t color) {
+  framebuffer[(TFT_WIDTH * y) + x] = color;
+}
+
+void TFT_LTDC::DrawRect(uint16_t sx, uint16_t sy, uint16_t ex, uint16_t ey, uint16_t color) {
+
+  if (sx == ex || sy == ey) return;
+
+  uint16_t offline = TFT_WIDTH - (ex - sx);
+  uint32_t addr = (uint32_t)&framebuffer[(TFT_WIDTH * sy) + sx];
+
+  CBI(DMA2D->CR, 0);
+  DMA2D->CR = 3 << 16;
+  DMA2D->OPFCCR = 0X02;
+  DMA2D->OOR = offline;
+  DMA2D->OMAR = addr;
+  DMA2D->NLR = (ey - sy) | ((ex - sx) << 16);
+  DMA2D->OCOLR = color;
+  SBI(DMA2D->CR, 0);
+
+  uint32_t timeout = 0;
+  while (!TEST(DMA2D->ISR, 1)) {
+    timeout++;
+    if (timeout > 0x1FFFFF) break;
+  }
+  SBI(DMA2D->IFCR, 1);
+}
+
+void TFT_LTDC::DrawImage(uint16_t sx, uint16_t sy, uint16_t ex, uint16_t ey, uint16_t *colors) {
+
+  if (sx == ex || sy == ey) return;
+
+  uint16_t offline = TFT_WIDTH - (ex - sx);
+  uint32_t addr = (uint32_t)&framebuffer[(TFT_WIDTH * sy) + sx];
+
+  CBI(DMA2D->CR, 0);
+  DMA2D->CR = 0 << 16;
+  DMA2D->FGPFCCR = 0X02;
+  DMA2D->FGOR = 0;
+  DMA2D->OOR = offline;
+  DMA2D->FGMAR = (uint32_t)colors;
+  DMA2D->OMAR = addr;
+  DMA2D->NLR = (ey - sy) | ((ex - sx) << 16);
+  SBI(DMA2D->CR, 0);
+
+  uint32_t timeout = 0;
+  while (!TEST(DMA2D->ISR, 1)) {
+    timeout++;
+    if (timeout > 0x1FFFFF) break;
+  }
+  SBI(DMA2D->IFCR, 1);
+}
+
+void TFT_LTDC::WriteData(uint16_t data) {
+  switch (reg) {
+    case 0x01: x_cur = x_min = data; return;
+    case 0x02: x_max = data; return;
+    case 0x03: y_cur = y_min = data; return;
+    case 0x04: y_max = data; return;
+  }
+  Transmit(data);
+}
+
+void TFT_LTDC::Transmit(tft_data_t Data) {
+  DrawPoint(x_cur, y_cur, Data);
+  x_cur++;
+  if (x_cur > x_max) {
+    x_cur = x_min;
+    y_cur++;
+    if (y_cur > y_max) y_cur = y_min;
+  }
+}
+
+void TFT_LTDC::WriteReg(uint16_t Reg) {
+  reg = Reg;
+}
+
+void TFT_LTDC::TransmitDMA(uint32_t MemoryIncrease, uint16_t *Data, uint16_t Count) {
+
+  while (x_cur != x_min && Count) {
+    Transmit(*Data);
+    if (MemoryIncrease == DMA_PINC_ENABLE) Data++;
+    Count--;
+  }
+
+  uint16_t width = x_max - x_min + 1;
+  uint16_t height = Count / width;
+  uint16_t x_end_cnt = Count - (width * height);
+
+  if (height) {
+    if (MemoryIncrease == DMA_PINC_ENABLE) {
+      DrawImage(x_min, y_cur, x_min + width, y_cur + height, Data);
+      Data += width * height;
+    } else {
+      DrawRect(x_min, y_cur, x_min + width, y_cur + height, *Data);
+    }
+    y_cur += height;
+  }
+
+  while (x_end_cnt) {
+    Transmit(*Data);
+    if (MemoryIncrease == DMA_PINC_ENABLE) Data++;
+    x_end_cnt--;
+  }
+}
+
+#endif // HAS_LTDC_TFT
+#endif // ARDUINO_ARCH_STM32 && !STM32GENERIC
@@ -0,0 +1,155 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#pragma once
+
+#include "../../../inc/MarlinConfig.h"
+
+#ifdef STM32H7xx
+  #include "stm32h7xx_hal.h"
+#else
+  #error "LTDC TFT is currently only supported on STM32H7 hardware."
+#endif
+
+#define DATASIZE_8BIT  SPI_DATASIZE_8BIT
+#define DATASIZE_16BIT SPI_DATASIZE_16BIT
+#define TFT_IO_DRIVER  TFT_LTDC
+
+#define TFT_DATASIZE DATASIZE_16BIT
+typedef uint16_t tft_data_t;
+
+class TFT_LTDC {
+  private:
+    static volatile uint16_t *framebuffer;
+    static uint16_t x_min, x_max, y_min, y_max, x_cur, y_cur;
+    static uint8_t reg;
+
+    static uint32_t ReadID(tft_data_t Reg);
+
+    static uint16_t ReadPoint(uint16_t x, uint16_t y);
+    static void DrawPoint(uint16_t x, uint16_t y, uint16_t color);
+    static void DrawRect(uint16_t sx, uint16_t sy, uint16_t ex, uint16_t ey, uint16_t color);
+    static void DrawImage(uint16_t sx, uint16_t sy, uint16_t ex, uint16_t ey, uint16_t *colors);
+    static void Transmit(tft_data_t Data);
+    static void TransmitDMA(uint32_t MemoryIncrease, uint16_t *Data, uint16_t Count);
+
+  public:
+    static void Init();
+    static uint32_t GetID();
+    static bool isBusy();
+    static void Abort() { /*__HAL_DMA_DISABLE(&DMAtx);*/ }
+
+    static void DataTransferBegin(uint16_t DataWidth = TFT_DATASIZE) {}
+    static void DataTransferEnd() {};
+
+    static void WriteData(uint16_t Data);
+    static void WriteReg(uint16_t Reg);
+
+    static void WriteSequence(uint16_t *Data, uint16_t Count) { TransmitDMA(DMA_PINC_ENABLE, Data, Count); }
+    static void WriteMultiple(uint16_t Color, uint16_t Count) { static uint16_t Data; Data = Color; TransmitDMA(DMA_PINC_DISABLE, &Data, Count); }
+    static void WriteMultiple(uint16_t Color, uint32_t Count) {
+      static uint16_t Data; Data = Color;
+      while (Count > 0) {
+        TransmitDMA(DMA_MINC_DISABLE, &Data, Count > 0xFFFF ? 0xFFFF : Count);
+        Count = Count > 0xFFFF ? Count - 0xFFFF : 0;
+      }
+    }
+};
+
+const PinMap PinMap_LTDC[] = {
+  {PF_10, LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_DE
+  {PG_7,  LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_CLK
+  {PI_9,  LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_VSYNC
+  {PI_10, LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_HSYNC
+
+  {PG_6,  LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_R7
+  {PH_12, LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_R6
+  {PH_11, LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_R5
+  {PH_10, LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_R4
+  {PH_9,  LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_R3
+
+  {PI_2,  LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_G7
+  {PI_1,  LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_G6
+  {PI_0,  LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_G5
+  {PH_15, LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_G4
+  {PH_14, LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_G3
+  {PH_13, LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_G2
+
+  {PI_7,  LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_B7
+  {PI_6,  LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_B6
+  {PI_5,  LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_B5
+  {PI_4,  LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_B4
+  {PG_11, LTDC, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF14_LTDC)}, // LCD_B3
+  {NC,    NP,    0}
+};
+
+const PinMap PinMap_SDRAM[] = {
+  {PC_0,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_SDNWE
+  {PC_2,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_SDNE0
+  {PC_3,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_SDCKE0
+  {PE_0,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_NBL0
+  {PE_1,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_NBL1
+  {PF_11, FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_SDNRAS
+  {PG_8,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_SDCLK
+  {PG_15, FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_SDNCAS
+  {PG_4,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_BA0
+  {PG_5,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_BA1
+  {PD_14, FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_D0
+  {PD_15, FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_D1
+  {PD_0,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_D2
+  {PD_1,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_D3
+  {PE_7,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_D4
+  {PE_8,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_D5
+  {PE_9,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_D6
+  {PE_10, FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_D7
+  {PE_11, FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_D8
+  {PE_12, FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_D9
+  {PE_13, FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_D10
+  {PE_14, FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_D11
+  {PE_15, FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_D12
+  {PD_8,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_D13
+  {PD_9,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_D14
+  {PD_10, FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_D15
+  {PF_0,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_A0
+  {PF_1,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_A1
+  {PF_2,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_A2
+  {PF_3,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_A3
+  {PF_4,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_A4
+  {PF_5,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_A5
+  {PF_12, FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_A6
+  {PF_13, FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_A7
+  {PF_14, FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_A8
+  {PF_15, FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_A9
+  {PG_0,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_A10
+  {PG_1,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_A11
+  {PG_2,  FMC_Bank1_R, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF12_FMC)}, // FMC_A12
+  {NC,    NP,    0}
+};
+
+const PinMap PinMap_QUADSPI[] = {
+  {PB_2,  QUADSPI, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF9_QUADSPI)}, // QUADSPI_CLK
+  {PB_10, QUADSPI, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF9_QUADSPI)}, // QUADSPI_BK1_NCS
+  {PF_6,  QUADSPI, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF9_QUADSPI)}, // QUADSPI_BK1_IO3
+  {PF_7,  QUADSPI, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF9_QUADSPI)}, // QUADSPI_BK1_IO2
+  {PF_8,  QUADSPI, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF10_QUADSPI)}, // QUADSPI_BK1_IO0
+  {PF_9,  QUADSPI, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF10_QUADSPI)}, // QUADSPI_BK1_IO1
+  {NC,    NP,    0}
+};
@@ -207,12 +207,12 @@ void TFT_SPI::Transmit(uint16_t Data) {
  while ((SPIx.Instance->SR & SPI_FLAG_BSY) == SPI_FLAG_BSY) {}

  if (TFT_MISO_PIN != TFT_MOSI_PIN)
-    __HAL_SPI_CLEAR_OVRFLAG(&SPIx);   /* Clear overrun flag in 2 Lines communication mode because received is not read */
+    __HAL_SPI_CLEAR_OVRFLAG(&SPIx);   // Clear overrun flag in 2 Lines communication mode because received is not read
 }

 void TFT_SPI::TransmitDMA(uint32_t MemoryIncrease, uint16_t *Data, uint16_t Count) {
  // Wait last dma finish, to start another
-  while(isBusy()) { }
+  while (isBusy()) { /* nada */ }

  DMAtx.Init.MemInc = MemoryIncrease;
  HAL_DMA_Init(&DMAtx);
@@ -225,7 +225,7 @@ void TFT_SPI::TransmitDMA(uint32_t MemoryIncrease, uint16_t *Data, uint16_t Coun
  HAL_DMA_Start(&DMAtx, (uint32_t)Data, (uint32_t)&(SPIx.Instance->DR), Count);
  __HAL_SPI_ENABLE(&SPIx);

-  SET_BIT(SPIx.Instance->CR2, SPI_CR2_TXDMAEN);   /* Enable Tx DMA Request */
+  SET_BIT(SPIx.Instance->CR2, SPI_CR2_TXDMAEN);   // Enable Tx DMA Request

  HAL_DMA_PollForTransfer(&DMAtx, HAL_DMA_FULL_TRANSFER, HAL_MAX_DELAY);
  Abort();
@@ -23,7 +23,7 @@

 #include "../../../inc/MarlinConfig.h"

-#if HAS_TFT_XPT2046 || HAS_TOUCH_BUTTONS
+#if HAS_TFT_XPT2046 || HAS_RES_TOUCH_BUTTONS

 #include "xpt2046.h"
 #include "pinconfig.h"
@@ -74,7 +74,7 @@
 #elif defined(STM32F401xC) || defined(STM32F401xE)
  #define MCU_STEP_TIMER  9
  #define MCU_TEMP_TIMER 10
-#elif defined(STM32F4xx) || defined(STM32F7xx)
+#elif defined(STM32F4xx) || defined(STM32F7xx) || defined(STM32H7xx)
  #define MCU_STEP_TIMER  6           // STM32F401 has no TIM6, TIM7, or TIM8
  #define MCU_TEMP_TIMER 14           // TIM7 is consumed by Software Serial if used.
 #endif
@@ -21,15 +21,12 @@
 */
 #pragma once

-#include <stdint.h>
 #include "../../inc/MarlinConfig.h"

 // ------------------------
 // Defines
 // ------------------------

-#define FORCE_INLINE __attribute__((always_inline)) inline
-
 // STM32 timers may be 16 or 32 bit. Limiting HAL_TIMER_TYPE_MAX to 16 bits
 // avoids issues with STM32F0 MCUs, which seem to pause timers if UINT32_MAX
 // is written to the register. STM32F4 timers do not manifest this issue,
@@ -110,7 +110,7 @@ uint8_t BulkStorage::Read(uint8_t lun, uint32_t addr, uint16_t bsize, uint8_t bl
 }

 uint8_t BulkStorage::Write(uint8_t lun, uint32_t addr, uint16_t bsize, uint8_t blocks, const uint8_t * buf) {
-  return USBH_MSC_Write(&hUsbHost, lun, addr, const_cast <uint8_t*>(buf), blocks) != USBH_OK;
+  return USBH_MSC_Write(&hUsbHost, lun, addr, const_cast<uint8_t*>(buf), blocks) != USBH_OK;
 }

 #endif // USE_OTG_USB_HOST && USBHOST
@@ -84,7 +84,7 @@

 #if defined(SERIAL_USB) && !HAS_SD_HOST_DRIVE
  USBSerial SerialUSB;
-  DefaultSerial MSerial(true, SerialUSB);
+  DefaultSerial1 MSerial0(true, SerialUSB);

  #if ENABLED(EMERGENCY_PARSER)
    #include "../libmaple/usb/stm32f1/usb_reg_map.h"
@@ -107,7 +107,7 @@
      len = usb_cdcacm_peek(buf, total);

      for (uint32 i = 0; i < len; i++)
-        emergency_parser.update(MSerial.emergency_state, buf[i + total - len]);
+        emergency_parser.update(MSerial0.emergency_state, buf[i + total - len]);
    }
  #endif
 #endif
@@ -132,6 +132,9 @@ const uint8_t adc_pins[] = {
  #if HAS_TEMP_CHAMBER
    TEMP_CHAMBER_PIN,
  #endif
+  #if HAS_TEMP_COOLER
+    TEMP_COOLER_PIN,
+  #endif
  #if HAS_TEMP_ADC_1
    TEMP_1_PIN,
  #endif
@@ -189,6 +192,9 @@ enum TempPinIndex : char {
  #if HAS_TEMP_CHAMBER
    TEMP_CHAMBER,
  #endif
+  #if HAS_TEMP_COOLER
+    TEMP_COOLER_PIN,
+  #endif
  #if HAS_TEMP_ADC_1
    TEMP_1,
  #endif
@@ -272,6 +278,8 @@ static void NVIC_SetPriorityGrouping(uint32_t PriorityGroup) {
  } }
 #endif

+TERN_(POSTMORTEM_DEBUGGING, extern void install_min_serial());
+
 void HAL_init() {
  NVIC_SetPriorityGrouping(0x3);
  #if PIN_EXISTS(LED)
@@ -285,8 +293,9 @@ void HAL_init() {
  #if PIN_EXISTS(USB_CONNECT)
    OUT_WRITE(USB_CONNECT_PIN, !USB_CONNECT_INVERTING);  // USB clear connection
    delay(1000);                                         // Give OS time to notice
-    OUT_WRITE(USB_CONNECT_PIN, USB_CONNECT_INVERTING);
+    WRITE(USB_CONNECT_PIN, USB_CONNECT_INVERTING);
  #endif
+  TERN_(POSTMORTEM_DEBUGGING, install_min_serial());    // Install the minimal serial handler
 }

 // HAL idle task
@@ -382,6 +391,9 @@ void HAL_adc_start_conversion(const uint8_t adc_pin) {
    #if HAS_TEMP_CHAMBER
      case TEMP_CHAMBER_PIN: pin_index = TEMP_CHAMBER; break;
    #endif
+    #if HAS_TEMP_COOLER
+      case TEMP_COOLER_PIN: pin_index = TEMP_COOLER; break;
+    #endif
    #if HAS_TEMP_ADC_1
      case TEMP_1_PIN: pin_index = TEMP_1; break;
    #endif
@@ -441,6 +453,8 @@ void analogWrite(pin_t pin, int pwm_val8) {
    analogWrite(uint8_t(pin), pwm_val8);
 }

-void flashFirmware(const int16_t) { nvic_sys_reset(); }
+void HAL_reboot() { nvic_sys_reset(); }
+
+void flashFirmware(const int16_t) { HAL_reboot(); }

 #endif // __STM32F1__
@@ -36,7 +36,6 @@
 #include "fastio.h"
 #include "watchdog.h"

-
 #include <stdint.h>
 #include <util/atomic.h>

@@ -53,7 +52,7 @@
 // ------------------------

 #ifndef STM32_FLASH_SIZE
-  #if EITHER(MCU_STM32F103RE, MCU_STM32F103VE)
+  #if ANY(MCU_STM32F103RE, MCU_STM32F103VE, MCU_STM32F103ZE)
    #define STM32_FLASH_SIZE 512
  #else
    #define STM32_FLASH_SIZE 256
@@ -61,13 +60,12 @@
 #endif

 #ifdef SERIAL_USB
-  typedef ForwardSerial0Type< USBSerial > DefaultSerial;
-  extern DefaultSerial MSerial;
-
-  #if !HAS_SD_HOST_DRIVE
-    #define UsbSerial MSerial
-  #else
+  typedef ForwardSerial1Class< USBSerial > DefaultSerial1;
+  extern DefaultSerial1 MSerial0;
+  #if HAS_SD_HOST_DRIVE
    #define UsbSerial MarlinCompositeSerial
+  #else
+    #define UsbSerial MSerial0
  #endif
 #endif

@@ -81,24 +79,33 @@
 #endif

 #if SERIAL_PORT == -1
-  #define MYSERIAL0 UsbSerial
+  #define MYSERIAL1 UsbSerial
 #elif WITHIN(SERIAL_PORT, 1, NUM_UARTS)
-  #define MYSERIAL0 MSERIAL(SERIAL_PORT)
-#elif NUM_UARTS == 5
-  #error "SERIAL_PORT must be -1 or from 1 to 5. Please update your configuration."
+  #define MYSERIAL1 MSERIAL(SERIAL_PORT)
 #else
-  #error "SERIAL_PORT must be -1 or from 1 to 3. Please update your configuration."
+  #define MYSERIAL1 MSERIAL(1) // dummy port
+  static_assert(false, "SERIAL_PORT must be from 1 to " STRINGIFY(NUM_UARTS) ". You can also use -1 if the board supports Native USB.")
 #endif

 #ifdef SERIAL_PORT_2
  #if SERIAL_PORT_2 == -1
-    #define MYSERIAL1 UsbSerial
+    #define MYSERIAL2 UsbSerial
  #elif WITHIN(SERIAL_PORT_2, 1, NUM_UARTS)
-    #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
-  #elif NUM_UARTS == 5
-    #error "SERIAL_PORT_2 must be -1 or from 1 to 5. Please update your configuration."
+    #define MYSERIAL2 MSERIAL(SERIAL_PORT_2)
  #else
-    #error "SERIAL_PORT_2 must be -1 or from 1 to 3. Please update your configuration."
+    #define MYSERIAL2 MSERIAL(1) // dummy port
+    static_assert(false, "SERIAL_PORT_2 must be from 1 to " STRINGIFY(NUM_UARTS) ". You can also use -1 if the board supports Native USB.")
+  #endif
+#endif
+
+#ifdef SERIAL_PORT_3
+  #if SERIAL_PORT_3 == -1
+    #define MYSERIAL3 UsbSerial
+  #elif WITHIN(SERIAL_PORT_3, 1, NUM_UARTS)
+    #define MYSERIAL3 MSERIAL(SERIAL_PORT_3)
+  #else
+    #define MYSERIAL3 MSERIAL(1) // dummy port
+    static_assert(false, "SERIAL_PORT_3 must be from 1 to " STRINGIFY(NUM_UARTS) ". You can also use -1 if the board supports Native USB.")
  #endif
 #endif

@@ -107,10 +114,9 @@
    #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."
+    #define MMU2_SERIAL MSERIAL(1) // dummy port
+    static_assert(false, "MMU2_SERIAL_PORT must be from 1 to " STRINGIFY(NUM_UARTS) ". You can also use -1 if the board supports Native USB.")
  #endif
 #endif

@@ -119,10 +125,9 @@
    #define LCD_SERIAL UsbSerial
  #elif WITHIN(LCD_SERIAL_PORT, 1, NUM_UARTS)
    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
-  #elif NUM_UARTS == 5
-    #error "LCD_SERIAL_PORT must be -1 or from 1 to 5. Please update your configuration."
  #else
-    #error "LCD_SERIAL_PORT must be -1 or from 1 to 3. Please update your configuration."
+    #define LCD_SERIAL MSERIAL(1) // dummy port
+    static_assert(false, "LCD_SERIAL_PORT must be from 1 to " STRINGIFY(NUM_UARTS) ". You can also use -1 if the board supports Native USB.")
  #endif
  #if HAS_DGUS_LCD
    #define SERIAL_GET_TX_BUFFER_FREE() LCD_SERIAL.availableForWrite()
@@ -195,7 +200,7 @@ void HAL_clear_reset_source();
 // Reset reason
 uint8_t HAL_get_reset_source();

-inline void HAL_reboot() {}  // reboot the board or restart the bootloader
+void HAL_reboot();

 void _delay_ms(const int delay);

@@ -0,0 +1,118 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2017 Victor Perez
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#ifdef __STM32F1__
+
+#include "../../inc/MarlinConfigPre.h"
+
+#if ENABLED(POSTMORTEM_DEBUGGING)
+
+#include "../shared/HAL_MinSerial.h"
+#include "watchdog.h"
+
+#include <libmaple/usart.h>
+#include <libmaple/rcc.h>
+#include <libmaple/nvic.h>
+
+/* Instruction Synchronization Barrier */
+#define isb() __asm__ __volatile__ ("isb" : : : "memory")
+
+/* Data Synchronization Barrier */
+#define dsb() __asm__ __volatile__ ("dsb" : : : "memory")
+
+static void TXBegin() {
+  #if !WITHIN(SERIAL_PORT, 1, 6)
+    #warning "Using POSTMORTEM_DEBUGGING requires a physical U(S)ART hardware in case of severe error."
+    #warning "Disabling the severe error reporting feature currently because the used serial port is not a HW port."
+  #else
+    // We use MYSERIAL1 here, so we need to figure out how to get the linked register
+    struct usart_dev* dev = MYSERIAL1.c_dev();
+
+    // Or use this if removing libmaple
+    // int irq = dev->irq_num;
+    // int nvicUART[] = { NVIC_USART1 /* = 37 */, NVIC_USART2 /* = 38 */, NVIC_USART3 /* = 39 */, NVIC_UART4 /* = 52 */, NVIC_UART5 /* = 53 */ };
+    // Disabling irq means setting the bit in the NVIC ICER register located at
+    // Disable UART interrupt in NVIC
+    nvic_irq_disable(dev->irq_num);
+
+    // Use this if removing libmaple
+    //SBI(NVIC_BASE->ICER[1], irq - 32);
+
+    // We NEED memory barriers to ensure Interrupts are actually disabled!
+    // ( https://dzone.com/articles/nvic-disabling-interrupts-on-arm-cortex-m-and-the )
+    dsb();
+    isb();
+
+    rcc_clk_disable(dev->clk_id);
+    rcc_clk_enable(dev->clk_id);
+
+    usart_reg_map *regs = dev->regs;
+    regs->CR1 = 0; // Reset the USART
+    regs->CR2 = 0; // 1 stop bit
+
+    // If we don't touch the BRR (baudrate register), we don't need to recompute. Else we would need to call
+    usart_set_baud_rate(dev, 0, BAUDRATE);
+
+    regs->CR1 = (USART_CR1_TE | USART_CR1_UE); // 8 bits, no parity, 1 stop bit
+  #endif
+}
+
+// A SW memory barrier, to ensure GCC does not overoptimize loops
+#define sw_barrier() __asm__ volatile("": : :"memory");
+static void TX(char c) {
+  #if WITHIN(SERIAL_PORT, 1, 6)
+    struct usart_dev* dev = MYSERIAL1.c_dev();
+    while (!(dev->regs->SR & USART_SR_TXE)) {
+      TERN_(USE_WATCHDOG, HAL_watchdog_refresh());
+      sw_barrier();
+    }
+    dev->regs->DR = c;
+  #endif
+}
+
+void install_min_serial() {
+  HAL_min_serial_init = &TXBegin;
+  HAL_min_serial_out = &TX;
+}
+
+#if DISABLED(DYNAMIC_VECTORTABLE) && DISABLED(STM32F0xx) // Cortex M0 can't branch to a symbol that's too far, so we have a specific hack for them
+extern "C" {
+  __attribute__((naked)) void JumpHandler_ASM() {
+    __asm__ __volatile__ (
+      "b CommonHandler_ASM\n"
+    );
+  }
+  void __attribute__((naked, alias("JumpHandler_ASM"), nothrow)) __exc_hardfault();
+  void __attribute__((naked, alias("JumpHandler_ASM"), nothrow)) __exc_busfault();
+  void __attribute__((naked, alias("JumpHandler_ASM"), nothrow)) __exc_usagefault();
+  void __attribute__((naked, alias("JumpHandler_ASM"), nothrow)) __exc_memmanage();
+  void __attribute__((naked, alias("JumpHandler_ASM"), nothrow)) __exc_nmi();
+  void __attribute__((naked, alias("JumpHandler_ASM"), nothrow)) __stm32reservedexception7();
+  void __attribute__((naked, alias("JumpHandler_ASM"), nothrow)) __stm32reservedexception8();
+  void __attribute__((naked, alias("JumpHandler_ASM"), nothrow)) __stm32reservedexception9();
+  void __attribute__((naked, alias("JumpHandler_ASM"), nothrow)) __stm32reservedexception10();
+  void __attribute__((naked, alias("JumpHandler_ASM"), nothrow)) __stm32reservedexception13();
+}
+#endif
+
+#endif // POSTMORTEM_DEBUGGING
+#endif // __STM32F1__
@@ -123,7 +123,7 @@ uint8_t spiRec() {
 *
 * @details Uses DMA
 */
-void spiRead(uint8_t* buf, uint16_t nbyte) {
+void spiRead(uint8_t *buf, uint16_t nbyte) {
  SPI.dmaTransfer(0, const_cast<uint8_t*>(buf), nbyte);
 }

@@ -146,7 +146,7 @@ void spiSend(uint8_t b) {
 *
 * @details Use DMA
 */
-void spiSendBlock(uint8_t token, const uint8_t* buf) {
+void spiSendBlock(uint8_t token, const uint8_t *buf) {
  SPI.send(token);
  SPI.dmaSend(const_cast<uint8_t*>(buf), 512);
 }
@@ -160,7 +160,7 @@ uint8_t spiRec(uint32_t chan) { return SPI.transfer(0xFF); }
 void spiSend(uint32_t chan, byte b) { SPI.send(b); }

 // Write buffer to specified SPI channel
-void spiSend(uint32_t chan, const uint8_t* buf, size_t n) {
+void spiSend(uint32_t chan, const uint8_t *buf, size_t n) {
  for (size_t p = 0; p < n; p++) spiSend(chan, buf[p]);
 }

@@ -60,7 +60,7 @@ static inline __always_inline void my_usart_irq(ring_buffer *rb, ring_buffer *wb
  }
  else if (srflags & USART_SR_ORE) {
    // overrun and empty data, just do a dummy read to clear ORE
-    // and prevent a raise condition where a continous interrupt stream (due to ORE set) occurs
+    // and prevent a raise condition where a continuous interrupt stream (due to ORE set) occurs
    // (see chapter "Overrun error" ) in STM32 reference manual
    regs->DR;
  }
@@ -134,12 +134,12 @@ constexpr bool IsSerialClassAllowed(const HardwareSerial&) { return false; }
 // If you encounter this error, replace SerialX with MSerialX, for example MSerial3.

 // Non-TMC ports were already validated in HAL.h, so do not require verbose error messages.
-#ifdef MYSERIAL0
-  CHECK_CFG_SERIAL(MYSERIAL0);
-#endif
 #ifdef MYSERIAL1
  CHECK_CFG_SERIAL(MYSERIAL1);
 #endif
+#ifdef MYSERIAL2
+  CHECK_CFG_SERIAL(MYSERIAL2);
+#endif
 #ifdef LCD_SERIAL
  CHECK_CFG_SERIAL(LCD_SERIAL);
 #endif
@@ -47,7 +47,7 @@ struct MarlinSerial : public HardwareSerial {
  #endif
 };

-typedef Serial0Type<MarlinSerial> MSerialT;
+typedef Serial1Class<MarlinSerial> MSerialT;

 extern MSerialT MSerial1;
 extern MSerialT MSerial2;
@@ -19,14 +19,13 @@
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */
+#ifdef __STM32F1__

 /**
 * PersistentStore for Arduino-style EEPROM interface
 * with simple implementations supplied by Marlin.
 */

-#ifdef __STM32F1__
-
 #include "../../inc/MarlinConfig.h"

 #if ENABLED(IIC_BL24CXX_EEPROM)
@@ -48,13 +47,11 @@ bool PersistentStore::access_start()  { eeprom_init(); return true; }
 bool PersistentStore::access_finish() { return true; }

 bool PersistentStore::write_data(int &pos, const uint8_t *value, size_t size, uint16_t *crc) {
-  size_t written = 0;
+  uint16_t written = 0;
  while (size--) {
    uint8_t v = *value;
    uint8_t * const p = (uint8_t * const)pos;
-    // EEPROM has only ~100,000 write cycles,
-    // so only write bytes that have changed!
-    if (v != eeprom_read_byte(p)) {
+    if (v != eeprom_read_byte(p)) { // EEPROM has only ~100,000 write cycles, so only write bytes that have changed!
      eeprom_write_byte(p, v);
      if (++written & 0x7F) delay(2); else safe_delay(2); // Avoid triggering watchdog during long EEPROM writes
      if (eeprom_read_byte(p) != v) {
@@ -48,8 +48,8 @@ static uint8_t ram_eeprom[MARLIN_EEPROM_SIZE] __attribute__((aligned(4))) = {0};
 static bool eeprom_dirty = false;

 bool PersistentStore::access_start() {
-  const uint32_t* source = reinterpret_cast<const uint32_t*>(EEPROM_PAGE0_BASE);
-  uint32_t* destination = reinterpret_cast<uint32_t*>(ram_eeprom);
+  const uint32_t *source = reinterpret_cast<const uint32_t*>(EEPROM_PAGE0_BASE);
+  uint32_t *destination = reinterpret_cast<uint32_t*>(ram_eeprom);

  static_assert(0 == (MARLIN_EEPROM_SIZE) % 4, "MARLIN_EEPROM_SIZE is corrupted. (Must be a multiple of 4.)"); // Ensure copying as uint32_t is safe
  constexpr size_t eeprom_size_u32 = (MARLIN_EEPROM_SIZE) / 4;
--- a/Show More
+++ b/Show More