gcode_process.c

#include	"gcode_process.h"

/** \file
	\brief Work out what to do with received G-Code commands
*/

#include	<string.h>
#include	<avr/interrupt.h>

#include	"gcode_parse.h"

#include	"dda.h"
#include	"dda_queue.h"
#include	"watchdog.h"
#include	"delay.h"
#include	"serial.h"
#include	"sermsg.h"
#include	"temp.h"
#include	"heater.h"
#include	"timer.h"
#include	"sersendf.h"
#include	"pinio.h"
#include	"debug.h"
#include	"clock.h"
#include	"config.h"
#include	"home.h"

/// the current tool
uint8_t tool;

/// the tool to be changed when we get an M6
uint8_t next_tool;


/*
	private functions

	this is where we construct a move without a gcode command, useful for gcodes which require multiple moves eg; homing
*/

#if E_STARTSTOP_STEPS > 0
/// move E by a certain amount at a certain speed
static void SpecialMoveE(int32_t e, uint32_t f) {
	TARGET t = { 0L, 0L, 0L, e, f, 1 };
	enqueue(&t);
}
#endif /* E_STARTSTOP_STEPS > 0 */

/************************************************************************//**

  \brief Processes command stored in global \ref next_target.
  This is where we work out what to actually do with each command we
    receive. All data has already been scaled to integers in gcode_process.
    If you want to add support for a new G or M code, this is the place.


*//*************************************************************************/

void process_gcode_command() {
	uint32_t	backup_f;

	// convert relative to absolute
	if (next_target.option_all_relative) {
		next_target.target.X += startpoint.X;
		next_target.target.Y += startpoint.Y;
		next_target.target.Z += startpoint.Z;
	}

	// E relative movement.
	// Matches Sprinter's behaviour as of March 2012.
	if (next_target.option_all_relative || next_target.option_e_relative)
		next_target.target.e_relative = 1;
	else
		next_target.target.e_relative = 0;

	// implement axis limits
	#ifdef	X_MIN
		if (next_target.target.X < X_MIN * 1000.)
			next_target.target.X = X_MIN * 1000.;
	#endif
	#ifdef	X_MAX
		if (next_target.target.X > X_MAX * 1000.)
			next_target.target.X = X_MAX * 1000.;
	#endif
	#ifdef	Y_MIN
		if (next_target.target.Y < Y_MIN * 1000.)
			next_target.target.Y = Y_MIN * 1000.;
	#endif
	#ifdef	Y_MAX
		if (next_target.target.Y > Y_MAX * 1000.)
			next_target.target.Y = Y_MAX * 1000.;
	#endif
	#ifdef	Z_MIN
		if (next_target.target.Z < Z_MIN * 1000.)
			next_target.target.Z = Z_MIN * 1000.;
	#endif
	#ifdef	Z_MAX
		if (next_target.target.Z > Z_MAX * 1000.)
			next_target.target.Z = Z_MAX * 1000.;
	#endif


	// The GCode documentation was taken from http://reprap.org/wiki/Gcode .

	if (next_target.seen_T) {
	    //? --- T: Select Tool ---
	    //?
	    //? Example: T1
	    //?
	    //? Select extruder number 1 to build with.  Extruder numbering starts at 0.

	    next_tool = next_target.T;
	}

	if (next_target.seen_G) {
		uint8_t axisSelected = 0;
		switch (next_target.G) {
			case 0:
				//? G0: Rapid Linear Motion
				//?
				//? Example: G0 X12
				//?
				//? In this case move rapidly to X = 12 mm.  In fact, the RepRap firmware uses exactly the same code for rapid as it uses for controlled moves (see G1 below), as - for the RepRap machine - this is just as efficient as not doing so.  (The distinction comes from some old machine tools that used to move faster if the axes were not driven in a straight line.  For them G0 allowed any movement in space to get to the destination as fast as possible.)
				//?
				backup_f = next_target.target.F;
				next_target.target.F = MAXIMUM_FEEDRATE_X * 2L;
				enqueue(&next_target.target);
				next_target.target.F = backup_f;
				break;

			case 1:
				//? --- G1: Linear Motion at Feed Rate ---
				//?
				//? Example: G1 X90.6 Y13.8 E22.4
				//?
				//? Go in a straight line from the current (X, Y) point to the point (90.6, 13.8), extruding material as the move happens from the current extruded length to a length of 22.4 mm.
				//?
				enqueue(&next_target.target);
				break;

				//	G2 - Arc Clockwise
				// unimplemented

				//	G3 - Arc Counter-clockwise
				// unimplemented

			case 4:
				//? --- G4: Dwell ---
				//?
				//? Example: G4 P200
				//?
				//? In this case sit still doing nothing for 200 milliseconds.  During delays the state of the machine (for example the temperatures of its extruders) will still be preserved and controlled.
				//?
				queue_wait();
				// delay
				if (next_target.seen_P) {
					for (;next_target.P > 0;next_target.P--) {
						ifclock(clock_flag_10ms) {
							clock_10ms();
						}
						delay_ms(1);
					}
				}
				break;

			case 20:
				//? --- G20: Set Units to Inches ---
				//?
				//? Example: G20
				//?
				//? Units from now on are in inches.
				//?
				next_target.option_inches = 1;
				break;

			case 21:
				//? --- G21: Set Units to Millimeters ---
				//?
				//? Example: G21
				//?
				//? Units from now on are in millimeters.  (This is the RepRap default.)
				//?
				next_target.option_inches = 0;
				break;

			case 30:
				//? --- G30: Go home via point ---
				//?
				//? Undocumented.
				enqueue(&next_target.target);
				// no break here, G30 is move and then go home

			case 28:
				//? --- G28: Home ---
				//?
				//? Example: G28
				//?
				//? This causes the RepRap machine to move back to its X, Y and Z zero endstops.  It does so accelerating, so as to get there fast.  But when it arrives it backs off by 1 mm in each direction slowly, then moves back slowly to the stop.  This ensures more accurate positioning.
				//?
				//? If you add coordinates, then just the axes with coordinates specified will be zeroed.  Thus
				//?
				//? G28 X0 Y72.3
				//?
				//? will zero the X and Y axes, but not Z.  The actual coordinate values are ignored.
				//?

				queue_wait();

				if (next_target.seen_X) {
					#if defined	X_MIN_PIN
						home_x_negative();
					#elif defined X_MAX_PIN
						home_x_positive();
					#endif
					axisSelected = 1;
				}
				if (next_target.seen_Y) {
					#if defined	Y_MIN_PIN
						home_y_negative();
					#elif defined Y_MAX_PIN
						home_y_positive();
					#endif
					axisSelected = 1;
				}
				if (next_target.seen_Z) {
					#if defined Z_MAX_PIN
						home_z_positive();
					#elif defined	Z_MIN_PIN
						home_z_negative();
					#endif
					axisSelected = 1;
				}
				// there's no point in moving E, as E has no endstops

				if (!axisSelected) {
					home();
				}
				break;

			case 90:
				//? --- G90: Set to Absolute Positioning ---
				//?
				//? Example: G90
				//?
				//? All coordinates from now on are absolute relative to the origin
				//? of the machine. This is the RepRap default.
				//?
				//? If you ever want to switch back and forth between relative and
				//? absolute movement keep in mind, X, Y and Z follow the machine's
				//? coordinate system while E doesn't change it's position in the
				//? coordinate system on relative movements.
				//?

				// No wait_queue() needed.
				next_target.option_all_relative = 0;
				break;

			case 91:
				//? --- G91: Set to Relative Positioning ---
				//?
				//? Example: G91
				//?
				//? All coordinates from now on are relative to the last position.
				//?

				// No wait_queue() needed.
				next_target.option_all_relative = 1;
				break;

			case 92:
				//? --- G92: Set Position ---
				//?
				//? Example: G92 X10 E90
				//?
				//? Allows programming of absolute zero point, by reseting the current position to the values specified.  This would set the machine's X coordinate to 10, and the extrude coordinate to 90. No physical motion will occur.
				//?

				queue_wait();

				if (next_target.seen_X) {
					startpoint.X = next_target.target.X;
					axisSelected = 1;
				}
				if (next_target.seen_Y) {
					startpoint.Y = next_target.target.Y;
					axisSelected = 1;
				}
				if (next_target.seen_Z) {
					startpoint.Z = next_target.target.Z;
					axisSelected = 1;
				}
				if (next_target.seen_E) {
					startpoint.E = next_target.target.E;
					axisSelected = 1;
				}

				if (axisSelected == 0) {
					startpoint.X = next_target.target.X =
					startpoint.Y = next_target.target.Y =
					startpoint.Z = next_target.target.Z =
					startpoint.E = next_target.target.E = 0;
				}

				dda_new_startpoint();
				break;

			case 161:
				//? --- G161: Home negative ---
				//?
				//? Find the minimum limit of the specified axes by searching for the limit switch.
				//?
				if (next_target.seen_X)
					home_x_negative();
				if (next_target.seen_Y)
					home_y_negative();
				if (next_target.seen_Z)
					home_z_negative();
				break;

			case 162:
				//? --- G162: Home positive ---
				//?
				//? Find the maximum limit of the specified axes by searching for the limit switch.
				//?
				if (next_target.seen_X)
					home_x_positive();
				if (next_target.seen_Y)
					home_y_positive();
				if (next_target.seen_Z)
					home_z_positive();
				break;

				// unknown gcode: spit an error
			default:
				sersendf_P(PSTR("E: Bad G-code %d"), next_target.G);
				// newline is sent from gcode_parse after we return
				return;
		}
		#ifdef	DEBUG
			if (DEBUG_POSITION && (debug_flags & DEBUG_POSITION))
				print_queue();
		#endif
	}
	else if (next_target.seen_M) {
		uint8_t i;

		switch (next_target.M) {
			case 0:
				//? --- M0: machine stop ---
				//?
				//? Example: M0
				//?
				//? http://linuxcnc.org/handbook/RS274NGC_3/RS274NGC_33a.html#1002379
				//? Unimplemented, especially the restart after the stop. Fall trough to M2.
				//?

			case 2:
				//? --- M2: program end ---
				//?
				//? Example: M2
				//?
				//? http://linuxcnc.org/handbook/RS274NGC_3/RS274NGC_33a.html#1002379
				//?
				queue_wait();
				for (i = 0; i < NUM_HEATERS; i++)
					temp_set(i, 0);
				power_off();
				break;

			case 112:
				//? --- M112: Emergency Stop ---
				//?
				//? Example: M112
				//?
				//? Any moves in progress are immediately terminated, then RepRap shuts down.  All motors and heaters are turned off.
				//? It can be started again by pressing the reset button on the master microcontroller.  See also M0.
				//?

				timer_stop();
				queue_flush();
				power_off();
				cli();
				for (;;)
					wd_reset();
				break;

			case 6:
				//? --- M6: tool change ---
				//?
				//? Undocumented.
				tool = next_tool;
				break;

			case 82:
				//? --- M82 - Set E codes absolute ---
				//?
				//? This is the default and overrides G90/G91.
				//? M82/M83 is not documented in the RepRap wiki, behaviour
				//? was taken from Sprinter as of March 2012.
				//?
				//? While E does relative movements, it doesn't change its
				//? position in the coordinate system. See also comment on G90.
				//?

				// No wait_queue() needed.
				next_target.option_e_relative = 0;
				break;

			case 83:
				//? --- M83 - Set E codes relative ---
				//?
				//? Counterpart to M82.
				//?

				// No wait_queue() needed.
				next_target.option_e_relative = 1;
				break;

			// M84- stop idle hold
			case 84:
				stepper_disable();
				x_disable();
				y_disable();
				z_disable();
				e_disable();
				break;

			// M3/M101- extruder on
			case 3:
			case 101:
				//? --- M101: extruder on ---
				//?
				//? Undocumented.
				if (temp_achieved() == 0) {
					enqueue(NULL);
				}
				#ifdef DC_EXTRUDER
					heater_set(DC_EXTRUDER, DC_EXTRUDER_PWM);
				#elif E_STARTSTOP_STEPS > 0
					do {
						// backup feedrate, move E very quickly then restore feedrate
						backup_f = startpoint.F;
						startpoint.F = MAXIMUM_FEEDRATE_E;
						SpecialMoveE(E_STARTSTOP_STEPS, MAXIMUM_FEEDRATE_E);
						startpoint.F = backup_f;
					} while (0);
				#endif
				break;

			// M102- extruder reverse

			// M5/M103- extruder off
			case 5:
			case 103:
				//? --- M103: extruder off ---
				//?
				//? Undocumented.
				#ifdef DC_EXTRUDER
					heater_set(DC_EXTRUDER, 0);
				#elif E_STARTSTOP_STEPS > 0
					do {
						// backup feedrate, move E very quickly then restore feedrate
						backup_f = startpoint.F;
						startpoint.F = MAXIMUM_FEEDRATE_E;
						SpecialMoveE(-E_STARTSTOP_STEPS, MAXIMUM_FEEDRATE_E);
						startpoint.F = backup_f;
					} while (0);
				#endif
				break;

			case 104:
				//? --- M104: Set Extruder Temperature (Fast) ---
				//?
				//? Example: M104 S190
				//?
				//? Set the temperature of the current extruder to 190<sup>o</sup>C and return control to the host immediately (''i.e.'' before that temperature has been reached by the extruder).  See also M109.
				//? Teacup supports an optional P parameter as a sensor index to address (eg M104 P1 S100 will set the bed temperature rather than the extruder temperature).
				//?
				if ( ! next_target.seen_S)
					break;
				if ( ! next_target.seen_P)
					next_target.P = HEATER_EXTRUDER;
				temp_set(next_target.P, next_target.S);
				if (next_target.S)
					power_on();
				break;

			case 105:
				//? --- M105: Get Extruder Temperature ---
				//?
				//? Example: M105
				//?
				//? Request the temperature of the current extruder and the build base in degrees Celsius.  The temperatures are returned to the host computer.  For example, the line sent to the host in response to this command looks like
				//?
				//? <tt>ok T:201 B:117</tt>
				//?
				//? Teacup supports an optional P parameter as a sensor index to address.
				//?
				#ifdef ENFORCE_ORDER
					queue_wait();
				#endif
				if ( ! next_target.seen_P)
					next_target.P = TEMP_SENSOR_none;
				temp_print(next_target.P);
				break;

			case 7:
			case 106:
				//? --- M106: Fan On ---
				//?
				//? Example: M106
				//?
				//? Turn on the cooling fan (if any).
				//?

				#ifdef ENFORCE_ORDER
					// wait for all moves to complete
					queue_wait();
				#endif
				#ifdef HEATER_FAN
					heater_set(HEATER_FAN, 255);
				#endif
				break;

			case 9:
			case 107:
				//? --- M107: Fan Off ---
				//?
				//? Example: M107
				//?
				//? Turn off the cooling fan (if any).
				//?

				#ifdef ENFORCE_ORDER
					// wait for all moves to complete
					queue_wait();
				#endif
				#ifdef HEATER_FAN
					heater_set(HEATER_FAN, 0);
				#endif
				break;

			case 109:
				//? --- M109: Set Extruder Temperature ---
				//?
				//? Example: M109 S190
				//?
				//? Set the temperature of the current extruder to 190<sup>o</sup>C and wait for it to reach that value before sending an acknowledgment to the host.  In fact the RepRap firmware waits a while after the temperature has been reached for the extruder to stabilise - typically about 40 seconds.  This can be changed by a parameter in the firmware configuration file when the firmware is compiled.  See also M104 and M116.
				//?
				//? Teacup supports an optional P parameter as a sensor index to address.
				//?
				if ( ! next_target.seen_S)
					break;
				if ( ! next_target.seen_P)
					next_target.P = HEATER_EXTRUDER;
				temp_set(next_target.P, next_target.S);
				if (next_target.S) {
					power_on();
					enable_heater();
				}
				else {
					disable_heater();
				}
				enqueue(NULL);
				break;

			case 110:
				//? --- M110: Set Current Line Number ---
				//?
				//? Example: N123 M110
				//?
				//? Set the current line number to 123.  Thus the expected next line after this command will be 124.
				//? This is a no-op in Teacup.
				//?
				break;

			#ifdef	DEBUG
			case 111:
				//? --- M111: Set Debug Level ---
				//?
				//? Example: M111 S6
				//?
				//? Set the level of debugging information transmitted back to the host to level 6.  The level is the OR of three bits:
				//?
				//? <Pre>
				//? #define         DEBUG_PID       1
				//? #define         DEBUG_DDA       2
				//? #define         DEBUG_POSITION  4
				//? </pre>
				//?
				//? This command is only available in DEBUG builds of Teacup.

				if ( ! next_target.seen_S)
					break;
				debug_flags = next_target.S;
				break;
			#endif

			// M113- extruder PWM

			case 114:
				//? --- M114: Get Current Position ---
				//?
				//? Example: M114
				//?
				//? This causes the RepRap machine to report its current X, Y, Z and E coordinates to the host.
				//?
				//? For example, the machine returns a string such as:
				//?
				//? <tt>ok C: X:0.00 Y:0.00 Z:0.00 E:0.00</tt>
				//?
				#ifdef ENFORCE_ORDER
					// wait for all moves to complete
					queue_wait();
				#endif
				update_current_position();
				sersendf_P(PSTR("X:%lq,Y:%lq,Z:%lq,E:%lq,F:%ld"), current_position.X, current_position.Y, current_position.Z, current_position.E, current_position.F);
				// newline is sent from gcode_parse after we return
				break;

			case 115:
				//? --- M115: Get Firmware Version and Capabilities ---
				//?
				//? Example: M115
				//?
				//? Request the Firmware Version and Capabilities of the current microcontroller
				//? The details are returned to the host computer as key:value pairs separated by spaces and terminated with a linefeed.
				//?
				//? sample data from firmware:
				//?  FIRMWARE_NAME:Teacup FIRMWARE_URL:http%%3A//github.com/triffid/Teacup_Firmware/ PROTOCOL_VERSION:1.0 MACHINE_TYPE:Mendel EXTRUDER_COUNT:1 TEMP_SENSOR_COUNT:1 HEATER_COUNT:1
				//?

				sersendf_P(PSTR("FIRMWARE_NAME:Teacup FIRMWARE_URL:http%%3A//github.com/triffid/Teacup_Firmware/ PROTOCOL_VERSION:1.0 MACHINE_TYPE:Mendel EXTRUDER_COUNT:%d TEMP_SENSOR_COUNT:%d HEATER_COUNT:%d"), 1, NUM_TEMP_SENSORS, NUM_HEATERS);
				// newline is sent from gcode_parse after we return
				break;

			case 116:
				//? --- M116: Wait ---
				//?
				//? Example: M116
				//?
				//? Wait for ''all'' temperatures and other slowly-changing variables to arrive at their set values.  See also M109.

				enqueue(NULL);
				break;

			case 130:
				//? --- M130: heater P factor ---
				//? Undocumented.
				if ( ! next_target.seen_P)
					next_target.P = HEATER_EXTRUDER;
				if (next_target.seen_S)
					pid_set_p(next_target.P, next_target.S);
				break;

			case 131:
				//? --- M131: heater I factor ---
				//? Undocumented.
				if ( ! next_target.seen_P)
					next_target.P = HEATER_EXTRUDER;
				if (next_target.seen_S)
					pid_set_i(next_target.P, next_target.S);
				break;

			case 132:
				//? --- M132: heater D factor ---
				//? Undocumented.
				if ( ! next_target.seen_P)
					next_target.P = HEATER_EXTRUDER;
				if (next_target.seen_S)
					pid_set_d(next_target.P, next_target.S);
				break;

			case 133:
				//? --- M133: heater I limit ---
				//? Undocumented.
				if ( ! next_target.seen_P)
					next_target.P = HEATER_EXTRUDER;
				if (next_target.seen_S)
					pid_set_i_limit(next_target.P, next_target.S);
				break;

			case 134:
				//? --- M134: save PID settings to eeprom ---
				//? Undocumented.
				heater_save_settings();
				break;

			case 135:
				//? --- M135: set heater output ---
				//? Undocumented.
				if ( ! next_target.seen_P)
					next_target.P = HEATER_EXTRUDER;
				if (next_target.seen_S) {
					heater_set(next_target.P, next_target.S);
					power_on();
				}
				break;

			#ifdef	DEBUG
			case 136:
				//? --- M136: PRINT PID settings to host ---
				//? Undocumented.
				//? This comand is only available in DEBUG builds.
				if ( ! next_target.seen_P)
					next_target.P = HEATER_EXTRUDER;
				heater_print(next_target.P);
				break;
			#endif

			case 140:
				//? --- M140: Set heated bed temperature ---
				//? Undocumented.
				#ifdef	HEATER_BED
					if ( ! next_target.seen_S)
						break;
					temp_set(HEATER_BED, next_target.S);
					if (next_target.S)
						power_on();
				#endif
				break;

			case 190:
				//? --- M190: Power On ---
				//? Undocumented.
				//? This one is pointless in Teacup. Implemented to calm the RepRap gurus.
				//?
				power_on();
				stepper_enable();
				x_enable();
				y_enable();
				z_enable();
				e_enable();
				break;

			case 191:
				//? --- M191: Power Off ---
				//? Undocumented.
				//? Same as M2. RepRap obviously prefers to invent new numbers instead of looking into standards. 
				#ifdef ENFORCE_ORDER
					// wait for all moves to complete
					queue_wait();
				#endif
				power_off();
				break;

			case 200:
				//? --- M200: report endstop status ---
				//? Report the current status of the endstops configured in the firmware to the host.
				power_on();
				#if defined(X_MIN_PIN)
					sersendf_P(PSTR("x_min:%d "), x_min());
				#endif
				#if defined(X_MAX_PIN)
					sersendf_P(PSTR("x_max:%d "), x_max());
				#endif
				#if defined(Y_MIN_PIN)
					sersendf_P(PSTR("y_min:%d "), y_min());
				#endif
				#if defined(Y_MAX_PIN)
					sersendf_P(PSTR("y_max:%d "), y_max());
				#endif
				#if defined(Z_MIN_PIN)
					sersendf_P(PSTR("z_min:%d "), z_min());
				#endif
				#if defined(Z_MAX_PIN)
					sersendf_P(PSTR("z_max:%d "), z_max());
				#endif
				#if !(defined(X_MIN_PIN) || defined(X_MAX_PIN) || defined(Y_MIN_PIN) || defined(Y_MAX_PIN) || defined(Z_MIN_PIN) || defined(Z_MAX_PIN))
					sersendf_P(PSTR("no endstops defined"));
				#endif
				break;

			#ifdef	DEBUG
			case 240:
				//? --- M240: echo off ---
				//? Disable echo.
				//? This command is only available in DEBUG builds.
				debug_flags &= ~DEBUG_ECHO;
				serial_writestr_P(PSTR("Echo off"));
				// newline is sent from gcode_parse after we return
				break;

			case 241:
				//? --- M241: echo on ---
				//? Enable echo.
				//? This command is only available in DEBUG builds.
				debug_flags |= DEBUG_ECHO;
				serial_writestr_P(PSTR("Echo on"));
				// newline is sent from gcode_parse after we return
				break;

			case 250:
				//? --- M250: return current position, end position, queue ---
				//? Undocumented
				//? This command is only available in DEBUG builds.
				update_current_position();
				sersendf_P(PSTR("{X:%ld,Y:%ld,Z:%ld,E:%ld,F:%lu,c:%lu}\t{X:%ld,Y:%ld,Z:%ld,E:%ld,F:%lu,c:%lu}\t"), current_position.X, current_position.Y, current_position.Z, current_position.E, current_position.F, movebuffer[mb_tail].c, movebuffer[mb_tail].endpoint.X, movebuffer[mb_tail].endpoint.Y, movebuffer[mb_tail].endpoint.Z, movebuffer[mb_tail].endpoint.E, movebuffer[mb_tail].endpoint.F,
					#ifdef ACCELERATION_REPRAP
						movebuffer[mb_tail].end_c
					#else
						movebuffer[mb_tail].c
					#endif
					);

				print_queue();
				break;

			case 253:
				//? --- M253: read arbitrary memory location ---
				//? Undocumented
				//? This command is only available in DEBUG builds.
				if ( ! next_target.seen_S)
					break;
				if ( ! next_target.seen_P)
					next_target.P = 1;
				for (; next_target.P; next_target.P--) {
					serwrite_hex8(*(volatile uint8_t *)(next_target.S));
					next_target.S++;
				}
				// newline is sent from gcode_parse after we return
				break;

			case 254:
				//? --- M254: write arbitrary memory location ---
				//? Undocumented
				//? This command is only available in DEBUG builds.
				if ( ! next_target.seen_S || ! next_target.seen_P)
					break;
				sersendf_P(PSTR("%x:%x->%x"), next_target.S, *(volatile uint8_t *)(next_target.S), next_target.P);
				(*(volatile uint8_t *)(next_target.S)) = next_target.P;
				// newline is sent from gcode_parse after we return
				break;
			#endif /* DEBUG */

				// unknown mcode: spit an error
			default:
				sersendf_P(PSTR("E: Bad M-code %d"), next_target.M);
				// newline is sent from gcode_parse after we return
		} // switch (next_target.M)
	} // else if (next_target.seen_M)
} // process_gcode_command()