Initial commit

5 files changed, 1327 insertions, 0 deletions

diff --git a/Marlin/src/feature/mmu/mmu.cpp b/Marlin/src/feature/mmu/mmu.cpp
new file mode 100644
index 0000000..9a44829
--- /dev/null
+++ b/Marlin/src/feature/mmu/mmu.cpp
@@ -0,0 +1,38 @@
+/**
+ * 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/>.
+ *
+ */
+
+#include "../../inc/MarlinConfig.h"
+
+#if HAS_PRUSA_MMU1
+
+#include "../module/stepper.h"
+
+void select_multiplexed_stepper(const uint8_t e) {
+  planner.synchronize();
+  disable_e_steppers();
+  WRITE(E_MUX0_PIN, TEST(e, 0) ? HIGH : LOW);
+  WRITE(E_MUX1_PIN, TEST(e, 1) ? HIGH : LOW);
+  WRITE(E_MUX2_PIN, TEST(e, 2) ? HIGH : LOW);
+  safe_delay(100);
+}
+
+#endif // HAS_PRUSA_MMU1
diff --git a/Marlin/src/feature/mmu/mmu.h b/Marlin/src/feature/mmu/mmu.h
new file mode 100644
index 0000000..10805c8
--- /dev/null
+++ b/Marlin/src/feature/mmu/mmu.h
@@ -0,0 +1,24 @@
+/**
+ * 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/>.
+ *
+ */
+#pragma once
+
+void select_multiplexed_stepper(const uint8_t e);
diff --git a/Marlin/src/feature/mmu/mmu2-serial-protocol.md b/Marlin/src/feature/mmu/mmu2-serial-protocol.md
new file mode 100644
index 0000000..7ff0901
--- /dev/null
+++ b/Marlin/src/feature/mmu/mmu2-serial-protocol.md
@@ -0,0 +1,94 @@
+Startup sequence
+================
+
+When initialized, MMU sends
+
+- MMU => 'start\n'
+
+We follow with
+
+- MMU <= 'S1\n'
+- MMU => 'ok*Firmware version*\n'
+- MMU <= 'S2\n'
+- MMU => 'ok*Build number*\n'
+
+#if (12V_mode)
+
+- MMU <= 'M1\n'
+- MMU => 'ok\n'
+
+#endif
+
+- MMU <= 'P0\n'
+- MMU => '*FINDA status*\n'
+
+Now we are sure MMU is available and ready. If there was a timeout or other communication problem somewhere, printer will be killed.
+
+- *Firmware version* is an integer value, but we don't care about it
+- *Build number* is an integer value and has to be >=126, or =>132 if 12V mode is enabled
+- *FINDA status* is 1 if the filament is loaded to the extruder, 0 otherwise
+
+
+*Build number* is checked against the required value, if it does not match, printer is halted.
+
+
+
+Toolchange
+==========
+
+- MMU <= 'T*Filament index*\n'
+
+MMU sends
+
+- MMU => 'ok\n'
+
+as soon as the filament is fed down to the extruder. We follow with
+
+- MMU <= 'C0\n'
+
+MMU will feed a few more millimeters of filament for the extruder gears to grab.
+When done, the MMU sends
+
+- MMU => 'ok\n'
+
+We don't wait for a response here but immediately continue with the next gcode which should
+be one or more extruder moves to feed the filament into the hotend.
+
+
+FINDA status
+============
+
+- MMU <= 'P0\n'
+- MMU => '*FINDA status*\n'
+
+*FINDA status* is 1 if the is filament loaded to the extruder, 0 otherwise. This could be used as filament runout sensor if probed regularly.
+
+
+
+Load filament
+=============
+
+- MMU <= 'L*Filament index*\n'
+
+MMU will feed filament down to the extruder, when done
+
+- MMU => 'ok\n'
+
+
+Unload filament
+=============
+
+- MMU <= 'U0\n'
+
+MMU will retract current filament from the extruder, when done
+
+- MMU => 'ok\n'
+
+
+
+Eject filament
+==============
+
+- MMU <= 'E*Filament index*\n'
+- MMU => 'ok\n'
+
diff --git a/Marlin/src/feature/mmu/mmu2.cpp b/Marlin/src/feature/mmu/mmu2.cpp
new file mode 100644
index 0000000..e303694
--- /dev/null
+++ b/Marlin/src/feature/mmu/mmu2.cpp
@@ -0,0 +1,1061 @@
+/**
+ * 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/>.
+ *
+ */
+
+#include "../../inc/MarlinConfig.h"
+
+#if HAS_PRUSA_MMU2
+
+#include "mmu2.h"
+#include "../../lcd/menu/menu_mmu2.h"
+
+MMU2 mmu2;
+
+#include "../../gcode/gcode.h"
+#include "../../lcd/marlinui.h"
+#include "../../libs/buzzer.h"
+#include "../../libs/nozzle.h"
+#include "../../module/temperature.h"
+#include "../../module/planner.h"
+#include "../../module/stepper/indirection.h"
+#include "../../MarlinCore.h"
+
+#if ENABLED(HOST_PROMPT_SUPPORT)
+  #include "../../feature/host_actions.h"
+#endif
+
+#if ENABLED(EXTENSIBLE_UI)
+  #include "../../lcd/extui/ui_api.h"
+#endif
+
+#define DEBUG_OUT ENABLED(MMU2_DEBUG)
+#include "../../core/debug_out.h"
+
+#define MMU_TODELAY 100
+#define MMU_TIMEOUT 10
+#define MMU_CMD_TIMEOUT 45000UL // 45s timeout for mmu commands (except P0)
+#define MMU_P0_TIMEOUT 3000UL   // Timeout for P0 command: 3seconds
+
+#define MMU2_COMMAND(S) tx_str_P(PSTR(S "\n"))
+
+#if ENABLED(MMU_EXTRUDER_SENSOR)
+  uint8_t mmu_idl_sens = 0;
+  static bool mmu_loading_flag = false;
+#endif
+
+#define MMU_CMD_NONE 0
+#define MMU_CMD_T0   0x10
+#define MMU_CMD_T1   0x11
+#define MMU_CMD_T2   0x12
+#define MMU_CMD_T3   0x13
+#define MMU_CMD_T4   0x14
+#define MMU_CMD_L0   0x20
+#define MMU_CMD_L1   0x21
+#define MMU_CMD_L2   0x22
+#define MMU_CMD_L3   0x23
+#define MMU_CMD_L4   0x24
+#define MMU_CMD_C0   0x30
+#define MMU_CMD_U0   0x40
+#define MMU_CMD_E0   0x50
+#define MMU_CMD_E1   0x51
+#define MMU_CMD_E2   0x52
+#define MMU_CMD_E3   0x53
+#define MMU_CMD_E4   0x54
+#define MMU_CMD_R0   0x60
+#define MMU_CMD_F0   0x70
+#define MMU_CMD_F1   0x71
+#define MMU_CMD_F2   0x72
+#define MMU_CMD_F3   0x73
+#define MMU_CMD_F4   0x74
+
+#define MMU_REQUIRED_FW_BUILDNR TERN(MMU2_MODE_12V, 132, 126)
+
+#define MMU2_NO_TOOL 99
+#define MMU_BAUD    115200
+
+bool MMU2::enabled, MMU2::ready, MMU2::mmu_print_saved;
+#if HAS_PRUSA_MMU2S
+  bool MMU2::mmu2s_triggered;
+#endif
+uint8_t MMU2::cmd, MMU2::cmd_arg, MMU2::last_cmd, MMU2::extruder;
+int8_t MMU2::state = 0;
+volatile int8_t MMU2::finda = 1;
+volatile bool MMU2::finda_runout_valid;
+int16_t MMU2::version = -1, MMU2::buildnr = -1;
+millis_t MMU2::prev_request, MMU2::prev_P0_request;
+char MMU2::rx_buffer[MMU_RX_SIZE], MMU2::tx_buffer[MMU_TX_SIZE];
+
+struct E_Step {
+  float extrude;        //!< extrude distance in mm
+  feedRate_t feedRate;  //!< feed rate in mm/s
+};
+
+static constexpr E_Step
+    ramming_sequence[] PROGMEM = { MMU2_RAMMING_SEQUENCE }
+  , load_to_nozzle_sequence[] PROGMEM = { MMU2_LOAD_TO_NOZZLE_SEQUENCE }
+  #if HAS_PRUSA_MMU2S
+    , can_load_sequence[] PROGMEM = { MMU2_CAN_LOAD_SEQUENCE }
+    , can_load_increment_sequence[] PROGMEM = { MMU2_CAN_LOAD_INCREMENT_SEQUENCE }
+  #endif
+;
+
+MMU2::MMU2() {
+  rx_buffer[0] = '\0';
+}
+
+void MMU2::init() {
+
+  set_runout_valid(false);
+
+  #if PIN_EXISTS(MMU2_RST)
+    WRITE(MMU2_RST_PIN, HIGH);
+    SET_OUTPUT(MMU2_RST_PIN);
+  #endif
+
+  MMU2_SERIAL.begin(MMU_BAUD);
+  extruder = MMU2_NO_TOOL;
+
+  safe_delay(10);
+  reset();
+  rx_buffer[0] = '\0';
+  state = -1;
+}
+
+void MMU2::reset() {
+  DEBUG_ECHOLNPGM("MMU <= reset");
+
+  #if PIN_EXISTS(MMU2_RST)
+    WRITE(MMU2_RST_PIN, LOW);
+    safe_delay(20);
+    WRITE(MMU2_RST_PIN, HIGH);
+  #else
+    MMU2_COMMAND("X0"); // Send soft reset
+  #endif
+}
+
+uint8_t MMU2::get_current_tool() {
+  return extruder == MMU2_NO_TOOL ? -1 : extruder;
+}
+
+#if EITHER(HAS_PRUSA_MMU2S, MMU_EXTRUDER_SENSOR)
+  #define FILAMENT_PRESENT() (READ(FIL_RUNOUT1_PIN) != FIL_RUNOUT1_STATE)
+#endif
+
+void MMU2::mmu_loop() {
+
+  switch (state) {
+
+    case 0: break;
+
+    case -1:
+      if (rx_start()) {
+        prev_P0_request = millis();   // Initialize finda sensor timeout
+
+        DEBUG_ECHOLNPGM("MMU => 'start'");
+        DEBUG_ECHOLNPGM("MMU <= 'S1'");
+
+        MMU2_COMMAND("S1");   // Read Version
+        state = -2;
+      }
+      else if (millis() > 3000000) {
+        SERIAL_ECHOLNPGM("MMU not responding - DISABLED");
+        state = 0;
+      }
+      break;
+
+    case -2:
+      if (rx_ok()) {
+        sscanf(rx_buffer, "%huok\n", &version);
+
+        DEBUG_ECHOLNPAIR("MMU => ", version, "\nMMU <= 'S2'");
+
+        MMU2_COMMAND("S2");   // Read Build Number
+        state = -3;
+      }
+      break;
+
+    case -3:
+      if (rx_ok()) {
+        sscanf(rx_buffer, "%huok\n", &buildnr);
+
+        DEBUG_ECHOLNPAIR("MMU => ", buildnr);
+
+        check_version();
+
+        #if ENABLED(MMU2_MODE_12V)
+          DEBUG_ECHOLNPGM("MMU <= 'M1'");
+
+          MMU2_COMMAND("M1");   // Stealth Mode
+          state = -5;
+
+        #else
+          DEBUG_ECHOLNPGM("MMU <= 'P0'");
+
+          MMU2_COMMAND("P0");   // Read FINDA
+          state = -4;
+        #endif
+      }
+      break;
+
+    #if ENABLED(MMU2_MODE_12V)
+    case -5:
+      // response to M1
+      if (rx_ok()) {
+        DEBUG_ECHOLNPGM("MMU => ok");
+
+        DEBUG_ECHOLNPGM("MMU <= 'P0'");
+
+        MMU2_COMMAND("P0");   // Read FINDA
+        state = -4;
+      }
+      break;
+    #endif
+
+    case -4:
+      if (rx_ok()) {
+        sscanf(rx_buffer, "%hhuok\n", &finda);
+
+        DEBUG_ECHOLNPAIR("MMU => ", finda, "\nMMU - ENABLED");
+
+        enabled = true;
+        state = 1;
+        TERN_(HAS_PRUSA_MMU2S, mmu2s_triggered = false);
+      }
+      break;
+
+    case 1:
+      if (cmd) {
+        if (WITHIN(cmd, MMU_CMD_T0, MMU_CMD_T4)) {
+          // tool change
+          int filament = cmd - MMU_CMD_T0;
+          DEBUG_ECHOLNPAIR("MMU <= T", filament);
+          tx_printf_P(PSTR("T%d\n"), filament);
+          TERN_(MMU_EXTRUDER_SENSOR, mmu_idl_sens = 1); // enable idler sensor, if any
+          state = 3; // wait for response
+        }
+        else if (WITHIN(cmd, MMU_CMD_L0, MMU_CMD_L4)) {
+          // load
+          int filament = cmd - MMU_CMD_L0;
+          DEBUG_ECHOLNPAIR("MMU <= L", filament);
+          tx_printf_P(PSTR("L%d\n"), filament);
+          state = 3; // wait for response
+        }
+        else if (cmd == MMU_CMD_C0) {
+          // continue loading
+          DEBUG_ECHOLNPGM("MMU <= 'C0'");
+          MMU2_COMMAND("C0");
+          state = 3; // wait for response
+        }
+        else if (cmd == MMU_CMD_U0) {
+          // unload current
+          DEBUG_ECHOLNPGM("MMU <= 'U0'");
+
+          MMU2_COMMAND("U0");
+          state = 3; // wait for response
+        }
+        else if (WITHIN(cmd, MMU_CMD_E0, MMU_CMD_E4)) {
+          // eject filament
+          int filament = cmd - MMU_CMD_E0;
+          DEBUG_ECHOLNPAIR("MMU <= E", filament);
+          tx_printf_P(PSTR("E%d\n"), filament);
+          state = 3; // wait for response
+        }
+        else if (cmd == MMU_CMD_R0) {
+          // recover after eject
+          DEBUG_ECHOLNPGM("MMU <= 'R0'");
+          MMU2_COMMAND("R0");
+          state = 3; // wait for response
+        }
+        else if (WITHIN(cmd, MMU_CMD_F0, MMU_CMD_F4)) {
+          // filament type
+          int filament = cmd - MMU_CMD_F0;
+          DEBUG_ECHOPAIR("MMU <= F", filament, " ");
+          DEBUG_ECHO_F(cmd_arg, DEC);
+          DEBUG_EOL();
+          tx_printf_P(PSTR("F%d %d\n"), filament, cmd_arg);
+          state = 3; // wait for response
+        }
+
+        last_cmd = cmd;
+        cmd = MMU_CMD_NONE;
+      }
+      else if (ELAPSED(millis(), prev_P0_request + 300)) {
+        MMU2_COMMAND("P0"); // Read FINDA
+        state = 2; // wait for response
+      }
+
+      TERN_(HAS_PRUSA_MMU2S, check_filament());
+      break;
+
+    case 2:   // response to command P0
+      if (rx_ok()) {
+        sscanf(rx_buffer, "%hhuok\n", &finda);
+
+        // This is super annoying. Only activate if necessary
+        // if (finda_runout_valid) DEBUG_ECHOLNPAIR_F("MMU <= 'P0'\nMMU => ", finda, 6);
+
+        if (!finda && finda_runout_valid) filament_runout();
+        if (cmd == MMU_CMD_NONE) ready = true;
+        state = 1;
+      }
+      else if (ELAPSED(millis(), prev_request + MMU_P0_TIMEOUT)) // Resend request after timeout (3s)
+        state = 1;
+
+      TERN_(HAS_PRUSA_MMU2S, check_filament());
+      break;
+
+    case 3:   // response to mmu commands
+      #if ENABLED(MMU_EXTRUDER_SENSOR)
+        if (mmu_idl_sens) {
+          if (FILAMENT_PRESENT() && mmu_loading_flag) {
+            DEBUG_ECHOLNPGM("MMU <= 'A'");
+            MMU2_COMMAND("A"); // send 'abort' request
+            mmu_idl_sens = 0;
+            DEBUG_ECHOLNPGM("MMU IDLER_SENSOR = 0 - ABORT");
+          }
+        }
+      #endif
+
+      if (rx_ok()) {
+        #if HAS_PRUSA_MMU2S
+          // Respond to C0 MMU command in MMU2S model
+          const bool keep_trying = !mmu2s_triggered && last_cmd == MMU_CMD_C0;
+          if (keep_trying) {
+            // MMU ok received but filament sensor not triggered, retrying...
+            DEBUG_ECHOLNPGM("MMU => 'ok' (filament not present in gears)");
+            DEBUG_ECHOLNPGM("MMU <= 'C0' (keep trying)");
+            MMU2_COMMAND("C0");
+          }
+        #else
+          constexpr bool keep_trying = false;
+        #endif
+
+        if (!keep_trying) {
+          DEBUG_ECHOLNPGM("MMU => 'ok'");
+          ready = true;
+          state = 1;
+          last_cmd = MMU_CMD_NONE;
+        }
+      }
+      else if (ELAPSED(millis(), prev_request + MMU_CMD_TIMEOUT)) {
+        // resend request after timeout
+        if (last_cmd) {
+          DEBUG_ECHOLNPGM("MMU retry");
+          cmd = last_cmd;
+          last_cmd = MMU_CMD_NONE;
+        }
+        state = 1;
+      }
+      TERN_(HAS_PRUSA_MMU2S, check_filament());
+      break;
+  }
+}
+
+/**
+ * Check if MMU was started
+ */
+bool MMU2::rx_start() {
+  // check for start message
+  return rx_str_P(PSTR("start\n"));
+}
+
+/**
+ * Check if the data received ends with the given string.
+ */
+bool MMU2::rx_str_P(const char* str) {
+  uint8_t i = strlen(rx_buffer);
+
+  while (MMU2_SERIAL.available()) {
+    rx_buffer[i++] = MMU2_SERIAL.read();
+
+    if (i == sizeof(rx_buffer) - 1) {
+      DEBUG_ECHOLNPGM("rx buffer overrun");
+      break;
+    }
+  }
+  rx_buffer[i] = '\0';
+
+  uint8_t len = strlen_P(str);
+
+  if (i < len) return false;
+
+  str += len;
+
+  while (len--) {
+    char c0 = pgm_read_byte(str--), c1 = rx_buffer[i--];
+    if (c0 == c1) continue;
+    if (c0 == '\r' && c1 == '\n') continue;  // match cr as lf
+    if (c0 == '\n' && c1 == '\r') continue;  // match lf as cr
+    return false;
+  }
+  return true;
+}
+
+/**
+ * Transfer data to MMU, no argument
+ */
+void MMU2::tx_str_P(const char* str) {
+  clear_rx_buffer();
+  uint8_t len = strlen_P(str);
+  LOOP_L_N(i, len) MMU2_SERIAL.write(pgm_read_byte(str++));
+  prev_request = millis();
+}
+
+/**
+ * Transfer data to MMU, single argument
+ */
+void MMU2::tx_printf_P(const char* format, int argument = -1) {
+  clear_rx_buffer();
+  uint8_t len = sprintf_P(tx_buffer, format, argument);
+  LOOP_L_N(i, len) MMU2_SERIAL.write(tx_buffer[i]);
+  prev_request = millis();
+}
+
+/**
+ * Transfer data to MMU, two arguments
+ */
+void MMU2::tx_printf_P(const char* format, int argument1, int argument2) {
+  clear_rx_buffer();
+  uint8_t len = sprintf_P(tx_buffer, format, argument1, argument2);
+  LOOP_L_N(i, len) MMU2_SERIAL.write(tx_buffer[i]);
+  prev_request = millis();
+}
+
+/**
+ * Empty the rx buffer
+ */
+void MMU2::clear_rx_buffer() {
+  while (MMU2_SERIAL.available()) MMU2_SERIAL.read();
+  rx_buffer[0] = '\0';
+}
+
+/**
+ * Check if we received 'ok' from MMU
+ */
+bool MMU2::rx_ok() {
+  if (rx_str_P(PSTR("ok\n"))) {
+    prev_P0_request = millis();
+    return true;
+  }
+  return false;
+}
+
+/**
+ * Check if MMU has compatible firmware
+ */
+void MMU2::check_version() {
+  if (buildnr < MMU_REQUIRED_FW_BUILDNR) {
+    SERIAL_ERROR_MSG("Invalid MMU2 firmware. Version >= " STRINGIFY(MMU_REQUIRED_FW_BUILDNR) " required.");
+    kill(GET_TEXT(MSG_KILL_MMU2_FIRMWARE));
+  }
+}
+
+static void mmu2_not_responding() {
+  LCD_MESSAGEPGM(MSG_MMU2_NOT_RESPONDING);
+  BUZZ(100, 659);
+  BUZZ(200, 698);
+  BUZZ(100, 659);
+  BUZZ(300, 440);
+  BUZZ(100, 659);
+}
+
+#if HAS_PRUSA_MMU2S
+
+  bool MMU2::load_to_gears() {
+    command(MMU_CMD_C0);
+    manage_response(true, true);
+    LOOP_L_N(i, MMU2_C0_RETRY) {  // Keep loading until filament reaches gears
+      if (mmu2s_triggered) break;
+      command(MMU_CMD_C0);
+      manage_response(true, true);
+      check_filament();
+    }
+    const bool success = mmu2s_triggered && can_load();
+    if (!success) mmu2_not_responding();
+    return success;
+  }
+
+  /**
+   * Handle tool change
+   */
+  void MMU2::tool_change(const uint8_t index) {
+
+    if (!enabled) return;
+
+    set_runout_valid(false);
+
+    if (index != extruder) {
+
+      DISABLE_AXIS_E0();
+      ui.status_printf_P(0, GET_TEXT(MSG_MMU2_LOADING_FILAMENT), int(index + 1));
+
+      command(MMU_CMD_T0 + index);
+      manage_response(true, true);
+
+      if (load_to_gears()) {
+        extruder = index; // filament change is finished
+        active_extruder = 0;
+        ENABLE_AXIS_E0();
+        SERIAL_ECHO_START();
+        SERIAL_ECHOLNPAIR(STR_ACTIVE_EXTRUDER, int(extruder));
+      }
+      ui.reset_status();
+    }
+
+    set_runout_valid(true);
+  }
+
+  /**
+   * Handle special T?/Tx/Tc commands
+   *
+   * T? Gcode to extrude shouldn't have to follow, load to extruder wheels is done automatically
+   * Tx Same as T?, except nozzle doesn't have to be preheated. Tc must be placed after extruder nozzle is preheated to finish filament load.
+   * Tc Load to nozzle after filament was prepared by Tx and extruder nozzle is already heated.
+   */
+  void MMU2::tool_change(const char* special) {
+      if (!enabled) return;
+
+      set_runout_valid(false);
+
+      switch (*special) {
+        case '?': {
+          #if ENABLED(MMU2_MENUS)
+            const uint8_t index = mmu2_choose_filament();
+            while (!thermalManager.wait_for_hotend(active_extruder, false)) safe_delay(100);
+            load_filament_to_nozzle(index);
+          #else
+            BUZZ(400, 40);
+          #endif
+        } break;
+
+        case 'x': {
+          #if ENABLED(MMU2_MENUS)
+            planner.synchronize();
+            const uint8_t index = mmu2_choose_filament();
+            DISABLE_AXIS_E0();
+            command(MMU_CMD_T0 + index);
+            manage_response(true, true);
+
+            if (load_to_gears()) {
+              mmu_loop();
+              ENABLE_AXIS_E0();
+              extruder = index;
+              active_extruder = 0;
+            }
+          #else
+            BUZZ(400, 40);
+          #endif
+        } break;
+
+        case 'c': {
+          while (!thermalManager.wait_for_hotend(active_extruder, false)) safe_delay(100);
+          load_to_nozzle();
+        } break;
+      }
+
+      set_runout_valid(true);
+  }
+
+#elif ENABLED(MMU_EXTRUDER_SENSOR)
+
+  /**
+   * Handle tool change
+   */
+  void MMU2::tool_change(const uint8_t index) {
+    if (!enabled) return;
+
+    set_runout_valid(false);
+
+    if (index != extruder) {
+      DISABLE_AXIS_E0();
+      if (FILAMENT_PRESENT()) {
+        DEBUG_ECHOLNPGM("Unloading\n");
+        mmu_loading_flag = false;
+        command(MMU_CMD_U0);
+        manage_response(true, true);
+      }
+      ui.status_printf_P(0, GET_TEXT(MSG_MMU2_LOADING_FILAMENT), int(index + 1));
+      mmu_loading_flag = true;
+      command(MMU_CMD_T0 + index);
+      manage_response(true, true);
+      mmu_continue_loading();
+      command(MMU_CMD_C0);
+      extruder = index;
+      active_extruder = 0;
+
+      ENABLE_AXIS_E0();
+      SERIAL_ECHO_START();
+      SERIAL_ECHOLNPAIR(STR_ACTIVE_EXTRUDER, int(extruder));
+
+      ui.reset_status();
+    }
+
+    set_runout_valid(true);
+  }
+
+  /**
+   * Handle special T?/Tx/Tc commands
+   *
+   * T? Gcode to extrude shouldn't have to follow, load to extruder wheels is done automatically
+   * Tx Same as T?, except nozzle doesn't have to be preheated. Tc must be placed after extruder nozzle is preheated to finish filament load.
+   * Tc Load to nozzle after filament was prepared by Tx and extruder nozzle is already heated.
+   */
+  void MMU2::tool_change(const char* special) {
+    if (!enabled) return;
+
+    set_runout_valid(false);
+
+    switch (*special) {
+      case '?': {
+        DEBUG_ECHOLNPGM("case ?\n");
+        #if ENABLED(MMU2_MENUS)
+          uint8_t index = mmu2_choose_filament();
+          while (!thermalManager.wait_for_hotend(active_extruder, false)) safe_delay(100);
+          load_filament_to_nozzle(index);
+        #else
+          BUZZ(400, 40);
+        #endif
+      } break;
+
+      case 'x': {
+        DEBUG_ECHOLNPGM("case x\n");
+        #if ENABLED(MMU2_MENUS)
+          planner.synchronize();
+          uint8_t index = mmu2_choose_filament();
+          DISABLE_AXIS_E0();
+          command(MMU_CMD_T0 + index);
+          manage_response(true, true);
+          mmu_continue_loading();
+          command(MMU_CMD_C0);
+          mmu_loop();
+
+          ENABLE_AXIS_E0();
+          extruder = index;
+          active_extruder = 0;
+        #else
+          BUZZ(400, 40);
+        #endif
+      } break;
+
+      case 'c': {
+        DEBUG_ECHOLNPGM("case c\n");
+        while (!thermalManager.wait_for_hotend(active_extruder, false)) safe_delay(100);
+        execute_extruder_sequence((const E_Step *)load_to_nozzle_sequence, COUNT(load_to_nozzle_sequence));
+      } break;
+    }
+
+    set_runout_valid(true);
+  }
+
+  void MMU2::mmu_continue_loading() {
+    for (uint8_t i = 0; i < MMU_LOADING_ATTEMPTS_NR; i++) {
+      DEBUG_ECHOLNPAIR("Additional load attempt #", i);
+      if (FILAMENT_PRESENT()) break;
+      command(MMU_CMD_C0);
+      manage_response(true, true);
+    }
+    if (!FILAMENT_PRESENT()) {
+      DEBUG_ECHOLNPGM("Filament never reached sensor, runout");
+      filament_runout();
+    }
+    mmu_idl_sens = 0;
+  }
+
+#else // !HAS_PRUSA_MMU2S && !MMU_EXTRUDER_SENSOR
+
+  /**
+   * Handle tool change
+   */
+  void MMU2::tool_change(const uint8_t index) {
+    if (!enabled) return;
+
+    set_runout_valid(false);
+
+    if (index != extruder) {
+      DISABLE_AXIS_E0();
+      ui.status_printf_P(0, GET_TEXT(MSG_MMU2_LOADING_FILAMENT), int(index + 1));
+      command(MMU_CMD_T0 + index);
+      manage_response(true, true);
+      command(MMU_CMD_C0);
+      extruder = index; //filament change is finished
+      active_extruder = 0;
+      ENABLE_AXIS_E0();
+      SERIAL_ECHO_START();
+      SERIAL_ECHOLNPAIR(STR_ACTIVE_EXTRUDER, int(extruder));
+      ui.reset_status();
+    }
+
+    set_runout_valid(true);
+  }
+
+  /**
+   * Handle special T?/Tx/Tc commands
+   *
+   * T? Gcode to extrude shouldn't have to follow, load to extruder wheels is done automatically
+   * Tx Same as T?, except nozzle doesn't have to be preheated. Tc must be placed after extruder nozzle is preheated to finish filament load.
+   * Tc Load to nozzle after filament was prepared by Tx and extruder nozzle is already heated.
+   */
+  void MMU2::tool_change(const char* special) {
+    if (!enabled) return;
+
+    set_runout_valid(false);
+
+    switch (*special) {
+      case '?': {
+        DEBUG_ECHOLNPGM("case ?\n");
+        #if ENABLED(MMU2_MENUS)
+          uint8_t index = mmu2_choose_filament();
+          while (!thermalManager.wait_for_hotend(active_extruder, false)) safe_delay(100);
+          load_filament_to_nozzle(index);
+        #else
+          BUZZ(400, 40);
+        #endif
+      } break;
+
+      case 'x': {
+        DEBUG_ECHOLNPGM("case x\n");
+        #if ENABLED(MMU2_MENUS)
+          planner.synchronize();
+          uint8_t index = mmu2_choose_filament();
+          DISABLE_AXIS_E0();
+          command(MMU_CMD_T0 + index);
+          manage_response(true, true);
+          command(MMU_CMD_C0);
+          mmu_loop();
+
+          ENABLE_AXIS_E0();
+          extruder = index;
+          active_extruder = 0;
+        #else
+          BUZZ(400, 40);
+        #endif
+      } break;
+
+      case 'c': {
+        DEBUG_ECHOLNPGM("case c\n");
+        while (!thermalManager.wait_for_hotend(active_extruder, false)) safe_delay(100);
+        execute_extruder_sequence((const E_Step *)load_to_nozzle_sequence, COUNT(load_to_nozzle_sequence));
+      } break;
+    }
+
+    set_runout_valid(true);
+  }
+
+#endif // HAS_PRUSA_MMU2S
+
+/**
+ * Set next command
+ */
+void MMU2::command(const uint8_t mmu_cmd) {
+  if (!enabled) return;
+  cmd = mmu_cmd;
+  ready = false;
+}
+
+/**
+ * Wait for response from MMU
+ */
+bool MMU2::get_response() {
+  while (cmd != MMU_CMD_NONE) idle();
+
+  while (!ready) {
+    idle();
+    if (state != 3) break;
+  }
+
+  const bool ret = ready;
+  ready = false;
+
+  return ret;
+}
+
+/**
+ * Wait for response and deal with timeout if necessary
+ */
+void MMU2::manage_response(const bool move_axes, const bool turn_off_nozzle) {
+
+  constexpr xyz_pos_t park_point = NOZZLE_PARK_POINT;
+  bool response = false;
+  mmu_print_saved = false;
+  xyz_pos_t resume_position;
+  int16_t resume_hotend_temp = thermalManager.degTargetHotend(active_extruder);
+
+  KEEPALIVE_STATE(PAUSED_FOR_USER);
+
+  while (!response) {
+
+    response = get_response(); // wait for "ok" from mmu
+
+    if (!response) {          // No "ok" was received in reserved time frame, user will fix the issue on mmu unit
+      if (!mmu_print_saved) { // First occurrence. Save current position, park print head, disable nozzle heater.
+
+        planner.synchronize();
+
+        mmu_print_saved = true;
+
+        SERIAL_ECHOLNPGM("MMU not responding");
+
+        resume_hotend_temp = thermalManager.degTargetHotend(active_extruder);
+        resume_position = current_position;
+
+        if (move_axes && all_axes_homed())
+          nozzle.park(0, park_point /*= NOZZLE_PARK_POINT*/);
+
+        if (turn_off_nozzle) thermalManager.setTargetHotend(0, active_extruder);
+
+        mmu2_not_responding();
+      }
+    }
+    else if (mmu_print_saved) {
+      SERIAL_ECHOLNPGM("MMU starts responding\n");
+
+      if (turn_off_nozzle && resume_hotend_temp) {
+        thermalManager.setTargetHotend(resume_hotend_temp, active_extruder);
+        LCD_MESSAGEPGM(MSG_HEATING);
+        BUZZ(200, 40);
+
+        while (!thermalManager.wait_for_hotend(active_extruder, false)) safe_delay(1000);
+      }
+
+      if (move_axes && all_axes_homed()) {
+        LCD_MESSAGEPGM(MSG_MMU2_RESUMING);
+        BUZZ(198, 404); BUZZ(4, 0); BUZZ(198, 404);
+
+        // Move XY to starting position, then Z
+        do_blocking_move_to_xy(resume_position, feedRate_t(NOZZLE_PARK_XY_FEEDRATE));
+
+        // Move Z_AXIS to saved position
+        do_blocking_move_to_z(resume_position.z, feedRate_t(NOZZLE_PARK_Z_FEEDRATE));
+      }
+      else {
+        BUZZ(198, 404); BUZZ(4, 0); BUZZ(198, 404);
+        LCD_MESSAGEPGM(MSG_MMU2_RESUMING);
+      }
+    }
+  }
+}
+
+void MMU2::set_filament_type(const uint8_t index, const uint8_t filamentType) {
+  if (!enabled) return;
+
+  cmd_arg = filamentType;
+  command(MMU_CMD_F0 + index);
+
+  manage_response(true, true);
+}
+
+void MMU2::filament_runout() {
+  queue.inject_P(PSTR(MMU2_FILAMENT_RUNOUT_SCRIPT));
+  planner.synchronize();
+}
+
+#if HAS_PRUSA_MMU2S
+
+  void MMU2::check_filament() {
+    const bool present = FILAMENT_PRESENT();
+    if (cmd == MMU_CMD_NONE && last_cmd == MMU_CMD_C0) {
+      if (present && !mmu2s_triggered) {
+        DEBUG_ECHOLNPGM("MMU <= 'A'");
+        tx_str_P(PSTR("A\n"));
+      }
+      // Slowly spin the extruder during C0
+      else {
+        while (planner.movesplanned() < 3) {
+          current_position.e += 0.25;
+          line_to_current_position(MMM_TO_MMS(120));
+        }
+      }
+    }
+    mmu2s_triggered = present;
+  }
+
+  bool MMU2::can_load() {
+    execute_extruder_sequence((const E_Step *)can_load_sequence, COUNT(can_load_sequence));
+
+    int filament_detected_count = 0;
+    const int steps = (MMU2_CAN_LOAD_RETRACT) / (MMU2_CAN_LOAD_INCREMENT);
+    DEBUG_ECHOLNPGM("MMU can_load:");
+    LOOP_L_N(i, steps) {
+      execute_extruder_sequence((const E_Step *)can_load_increment_sequence, COUNT(can_load_increment_sequence));
+      check_filament(); // Don't trust the idle function
+      DEBUG_CHAR(mmu2s_triggered ? 'O' : 'o');
+      if (mmu2s_triggered) ++filament_detected_count;
+    }
+
+    if (filament_detected_count <= steps - (MMU2_CAN_LOAD_DEVIATION) / (MMU2_CAN_LOAD_INCREMENT)) {
+      DEBUG_ECHOLNPGM(" failed.");
+      return false;
+    }
+
+    DEBUG_ECHOLNPGM(" succeeded.");
+    return true;
+  }
+
+#endif
+
+// Load filament into MMU2
+void MMU2::load_filament(const uint8_t index) {
+  if (!enabled) return;
+
+  command(MMU_CMD_L0 + index);
+  manage_response(false, false);
+  BUZZ(200, 404);
+}
+
+/**
+ * Switch material and load to nozzle
+ */
+bool MMU2::load_filament_to_nozzle(const uint8_t index) {
+
+  if (!enabled) return false;
+
+  if (thermalManager.tooColdToExtrude(active_extruder)) {
+    BUZZ(200, 404);
+    LCD_ALERTMESSAGEPGM(MSG_HOTEND_TOO_COLD);
+    return false;
+  }
+
+  DISABLE_AXIS_E0();
+  command(MMU_CMD_T0 + index);
+  manage_response(true, true);
+
+  const bool success = load_to_gears();
+  if (success) {
+    mmu_loop();
+    extruder = index;
+    active_extruder = 0;
+    load_to_nozzle();
+    BUZZ(200, 404);
+  }
+  return success;
+}
+
+/**
+ * Load filament to nozzle of multimaterial printer
+ *
+ * This function is used only after T? (user select filament) and M600 (change filament).
+ * It is not used after T0 .. T4 command (select filament), in such case, gcode is responsible for loading
+ * filament to nozzle.
+ */
+void MMU2::load_to_nozzle() {
+  execute_extruder_sequence((const E_Step *)load_to_nozzle_sequence, COUNT(load_to_nozzle_sequence));
+}
+
+bool MMU2::eject_filament(const uint8_t index, const bool recover) {
+
+  if (!enabled) return false;
+
+  if (thermalManager.tooColdToExtrude(active_extruder)) {
+    BUZZ(200, 404);
+    LCD_ALERTMESSAGEPGM(MSG_HOTEND_TOO_COLD);
+    return false;
+  }
+
+  LCD_MESSAGEPGM(MSG_MMU2_EJECTING_FILAMENT);
+
+  ENABLE_AXIS_E0();
+  current_position.e -= MMU2_FILAMENTCHANGE_EJECT_FEED;
+  line_to_current_position(MMM_TO_MMS(2500));
+  planner.synchronize();
+  command(MMU_CMD_E0 + index);
+  manage_response(false, false);
+
+  if (recover)  {
+    LCD_MESSAGEPGM(MSG_MMU2_EJECT_RECOVER);
+    BUZZ(200, 404);
+    TERN_(HOST_PROMPT_SUPPORT, host_prompt_do(PROMPT_USER_CONTINUE, PSTR("MMU2 Eject Recover"), CONTINUE_STR));
+    TERN_(EXTENSIBLE_UI, ExtUI::onUserConfirmRequired_P(PSTR("MMU2 Eject Recover")));
+    wait_for_user_response();
+    BUZZ(200, 404);
+    BUZZ(200, 404);
+
+    command(MMU_CMD_R0);
+    manage_response(false, false);
+  }
+
+  ui.reset_status();
+
+  // no active tool
+  extruder = MMU2_NO_TOOL;
+
+  set_runout_valid(false);
+
+  BUZZ(200, 404);
+
+  DISABLE_AXIS_E0();
+
+  return true;
+}
+
+/**
+ * Unload from hotend and retract to MMU
+ */
+bool MMU2::unload() {
+
+  if (!enabled) return false;
+
+  if (thermalManager.tooColdToExtrude(active_extruder)) {
+    BUZZ(200, 404);
+    LCD_ALERTMESSAGEPGM(MSG_HOTEND_TOO_COLD);
+    return false;
+  }
+
+  // Unload sequence to optimize shape of the tip of the unloaded filament
+  execute_extruder_sequence((const E_Step *)ramming_sequence, sizeof(ramming_sequence) / sizeof(E_Step));
+
+  command(MMU_CMD_U0);
+  manage_response(false, true);
+
+  BUZZ(200, 404);
+
+  // no active tool
+  extruder = MMU2_NO_TOOL;
+
+  set_runout_valid(false);
+
+  return true;
+}
+
+void MMU2::execute_extruder_sequence(const E_Step * sequence, int steps) {
+
+  planner.synchronize();
+  ENABLE_AXIS_E0();
+
+  const E_Step* step = sequence;
+
+  LOOP_L_N(i, steps) {
+    const float es = pgm_read_float(&(step->extrude));
+    const feedRate_t fr_mm_m = pgm_read_float(&(step->feedRate));
+
+    DEBUG_ECHO_START();
+    DEBUG_ECHOLNPAIR("E step ", es, "/", fr_mm_m);
+
+    current_position.e += es;
+    line_to_current_position(MMM_TO_MMS(fr_mm_m));
+    planner.synchronize();
+
+    step++;
+  }
+
+  DISABLE_AXIS_E0();
+}
+
+#endif // HAS_PRUSA_MMU2
diff --git a/Marlin/src/feature/mmu/mmu2.h b/Marlin/src/feature/mmu/mmu2.h
new file mode 100644
index 0000000..4326989
--- /dev/null
+++ b/Marlin/src/feature/mmu/mmu2.h
@@ -0,0 +1,110 @@
+/**
+ * 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/>.
+ *
+ */
+#pragma once
+
+#include "../../inc/MarlinConfig.h"
+
+#if HAS_FILAMENT_SENSOR
+  #include "../runout.h"
+#endif
+
+#if SERIAL_USB
+  #define MMU_RX_SIZE 256
+  #define MMU_TX_SIZE 256
+#else
+  #define MMU_RX_SIZE  16
+  #define MMU_TX_SIZE  16
+#endif
+
+struct E_Step;
+
+class MMU2 {
+public:
+  MMU2();
+
+  static void init();
+  static void reset();
+  static void mmu_loop();
+  static void tool_change(const uint8_t index);
+  static void tool_change(const char* special);
+  static uint8_t get_current_tool();
+  static void set_filament_type(const uint8_t index, const uint8_t type);
+
+  static bool unload();
+  static void load_filament(uint8_t);
+  static void load_all();
+  static bool load_filament_to_nozzle(const uint8_t index);
+  static bool eject_filament(const uint8_t index, const bool recover);
+
+private:
+  static bool rx_str_P(const char* str);
+  static void tx_str_P(const char* str);
+  static void tx_printf_P(const char* format, const int argument);
+  static void tx_printf_P(const char* format, const int argument1, const int argument2);
+  static void clear_rx_buffer();
+
+  static bool rx_ok();
+  static bool rx_start();
+  static void check_version();
+
+  static void command(const uint8_t cmd);
+  static bool get_response();
+  static void manage_response(const bool move_axes, const bool turn_off_nozzle);
+
+  static void load_to_nozzle();
+  static void execute_extruder_sequence(const E_Step * sequence, int steps);
+
+  static void filament_runout();
+
+  #if HAS_PRUSA_MMU2S
+    static bool mmu2s_triggered;
+    static void check_filament();
+    static bool can_load();
+    static bool load_to_gears();
+  #else
+    FORCE_INLINE static bool load_to_gears() { return true; }
+  #endif
+
+  #if ENABLED(MMU_EXTRUDER_SENSOR)
+    static void mmu_continue_loading();
+  #endif
+
+  static bool enabled, ready, mmu_print_saved;
+
+  static uint8_t cmd, cmd_arg, last_cmd, extruder;
+  static int8_t state;
+  static volatile int8_t finda;
+  static volatile bool finda_runout_valid;
+  static int16_t version, buildnr;
+  static millis_t prev_request, prev_P0_request;
+  static char rx_buffer[MMU_RX_SIZE], tx_buffer[MMU_TX_SIZE];
+
+  static inline void set_runout_valid(const bool valid) {
+    finda_runout_valid = valid;
+    #if HAS_FILAMENT_SENSOR
+      if (valid) runout.reset();
+    #endif
+  }
+
+};
+
+extern MMU2 mmu2;