1 files changed, 45 insertions, 0 deletions
diff --git a/Marlin/src/gcode/control/M999.cpp b/Marlin/src/gcode/control/M999.cpp
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+++ b/Marlin/src/gcode/control/M999.cpp
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+/**
+ * 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 "../gcode.h"
+
+#include "../../lcd/marlinui.h" // for lcd_reset_alert_level
+#include "../../MarlinCore.h"   // for marlin_state
+#include "../queue.h"           // for flush_and_request_resend
+
+/**
+ * M999: Restart after being stopped
+ *
+ * Default behavior is to flush the serial buffer and request
+ * a resend to the host starting on the last N line received.
+ *
+ * Sending "M999 S1" will resume printing without flushing the
+ * existing command buffer.
+ */
+void GcodeSuite::M999() {
+  marlin_state = MF_RUNNING;
+  ui.reset_alert_level();
+
+  if (parser.boolval('S')) return;
+
+  queue.flush_and_request_resend();
+}