Dual motor support for self-squaring gantry homing.

- New dual motor support feature for gantry CNC machines. An axis motor is  efficiently mirrored to a dedicated set of step and direction pins (D12/D13 or A3/A4) with no detectable loss of performance. Primarily used to independently home both sides of a dual-motor gantry with a pair of limit switches (second shared with Z-axis limit pin). When the limit switches are setup correctly, Grbl will self-square the gantry (and stay square if $1=255 is programmed). Beware use at your own risk! Grbl is not responsible for any damage to any machines.

- Dual axis motors is only supported on the X-axis or Y-axis. And deletes the spindle direction(D13) and optional coolant mist (A4) features to make room for the dual motor step and direction pins.

- Dual axis homing will automatically abort homing if one limit switch triggers and travels more than 5% (default) of the non-dual axis max travel setting. For example, if the X-axis has dual motors and one X-axis triggers during homing, Grbl will abort 5% of the Y-axis max travel and the other X-axis limit fails to trigger. This will help keep any misconfigurations or failed limit switches from damaging the machine, but not completely eliminate this risk. Please take all precautions and test thouroughly before using this.

- Dual axis motors supports two configurations:

- Support for Arduino CNC shield clones. For these, step/dir on pins D12/D13, and spindle enable is moved to A3 (old coolant enable), while coolant enable is moved to A4 (SDA pin). Variable spindle/laser mode option is NOT supported for this shield.

- Support for Protoneer CNC Shield v3.51. Step/dir on pins A3/A4, and  coolant enable is moved to D13 (old spindle direction pin). Variable spindle/laser mode option IS supported for this shield.

- Added Bob's CNC E3 and E4 CNC machine defaults.

doc/csv/alarm_codes_en_US.csv

@@ -8,3 +8,4 @@
 "7","Homing fail","Homing fail. Safety door was opened during homing cycle."
 "8","Homing fail","Homing fail. Pull off travel failed to clear limit switch. Try increasing pull-off setting or check wiring."
 "9","Homing fail","Homing fail. Could not find limit switch within search distances. Try increasing max travel, decreasing pull-off distance, or check wiring."
+"10","Homing fail","Homing fail. Second dual axis limit switch failed to trigger within configured search distance after first. Try increasing trigger fail distance or check wiring."

doc/csv/build_option_codes_en_US.csv

@@ -19,4 +19,5 @@ $,Restore EEPROM `$` settings command,Disabled
 I,Build info write user string command,Disabled
 E,Force sync upon EEPROM write,Disabled
 W,Force sync upon work coordinate offset change,Disabled
-L,Homing initialization auto-lock,Disabled
+L,Homing initialization auto-lock,Disabled
+2,Dual axis motors,Enabled

doc/log/commit_log_v1.1.txt

@@ -1,3 +1,40 @@
+----------------
+Date: 2018-11-12
+Author: Sonny Jeon
+Subject: Update grbl.h
+
+----------------
+Date: 2018-11-12
+Author: Sonny Jeon
+Subject: Update system.c
+
+Correct control pin state checking within pin change interrupt. Improper if-else statements could lead to missed signal.
+
+----------------
+Date: 2018-11-12
+Author: Sonny Jeon
+Subject: Update gcode.c
+
+If statement bug fix related to jog motion modal group error checking.
+
+----------------
+Date: 2018-06-14
+Author: Sonny Jeon
+Subject: Spindle/coolant rare bug fixes. Free more flash.
+
+[new] Altered the way default settings are stored and restored. Saved about 300 bytes(!) of flashed size. Should free up enough for certain configurations of CoreXY machines.
+
+[fix] When the optional M7 mist coolant IO was enabled, coolant overrides was not disabling correctly.
+
+[fix] Coolant override states was not restored correctly after a parking motion in certain situations. It would restore programmed state, rather than current overridden state.
+
+[fix] Now allow coolant overrides to operate during jogging motion.
+
+[fix] Invert control pin mask typo.
+
+[new] Added a new build info feedback mechanism for enabling the safety door input pin.
+
+
 ----------------
 Date: 2018-06-09
 Author: Jon

grbl/config.h

@@ -586,9 +586,11 @@
 // to ensure the laser doesn't inadvertently remain powered while at a stop and cause a fire.
 #define DISABLE_LASER_DURING_HOLD // Default enabled. Comment to disable.
 
-// Enables a piecewise linear model of the spindle PWM/speed output. Requires a solution by the
-// 'fit_nonlinear_spindle.py' script in the /doc/script folder of the repo. See file comments 
-// on how to gather spindle data and run the script to generate a solution.
+// This feature alters the spindle PWM/speed to a nonlinear output with a simple piecewise linear
+// curve. Useful for spindles that don't produce the right RPM from Grbl's standard spindle PWM 
+// linear model. Requires a solution by the 'fit_nonlinear_spindle.py' script in the /doc/script
+// folder of the repo. See file comments on how to gather spindle data and run the script to
+// generate a solution.
 // #define ENABLE_PIECEWISE_LINEAR_SPINDLE  // Default disabled. Uncomment to enable.
 
 // N_PIECES, RPM_MAX, RPM_MIN, RPM_POINTxx, and RPM_LINE_XX constants are all set and given by
@@ -610,6 +612,68 @@
 #define RPM_LINE_A4  1.203413e-01  // Used N_PIECES = 4. A and B constants of line 4.
 #define RPM_LINE_B4  1.151360e+03
 
+/* --------------------------------------------------------------------------------------- 
+  This optional dual axis feature is primarily for the homing cycle to locate two sides of 
+  a dual-motor gantry independently, i.e. self-squaring. This requires an additional limit
+  switch for the cloned motor. To self square, both limit switches on the cloned axis must
+  be physically positioned to trigger when the gantry is square. Highly recommend keeping  
+  the motors always enabled to ensure the gantry stays square with the $1=255 setting.
+
+  For Grbl on the Arduino Uno, the cloned axis limit switch must to be shared with and 
+  wired with z-axis limit pin due to the lack of available pins. The homing cycle must home
+  the z-axis and cloned axis in different cycles, which is already the default config.
+
+  The dual axis feature works by cloning an axis step output onto another pair of step
+  and direction pins. The step pulse and direction of the cloned motor can be set 
+  independently of the main axis motor. However to save precious flash and memory, this
+  dual axis feature must share the same settings (step/mm, max speed, acceleration) as the 
+  parent motor. This is NOT a feature for an independent fourth axis. Only a motor clone.
+
+  WARNING: Make sure to test the directions of your dual axis motors! They must be setup
+  to move the same direction BEFORE running your first homing cycle or any long motion!
+  Motors moving in opposite directions can cause serious damage to your machine! Use this 
+  dual axis feature at your own risk.
+*/
+// NOTE: This feature requires approximately 400 bytes of flash. Certain configurations can
+// run out of flash to fit on an Arduino 328p/Uno. Only X and Y axes are supported. Variable
+// spindle/laser mode IS supported, but only for one config option. Core XY, spindle direction
+// pin, and M7 mist coolant are disabled/not supported.
+// #define ENABLE_DUAL_AXIS	// Default disabled. Uncomment to enable.
+
+// Select the one axis to mirror another motor. Only X and Y axis is supported at this time.
+#define DUAL_AXIS_SELECT  X_AXIS  // Must be either X_AXIS or Y_AXIS
+
+// To prevent the homing cycle from racking the dual axis, when one limit triggers before the
+// other due to switch failure or noise, the homing cycle will automatically abort if the second 
+// motor's limit switch does not trigger within the three distance parameters defined below. 
+// Axis length percent will automatically compute a fail distance as a percentage of the max
+// travel of the other non-dual axis, i.e. if dual axis select is X_AXIS at 5.0%, then the fail 
+// distance will be computed as 5.0% of y-axis max travel. Fail distance max and min are the 
+// limits of how far or little a valid fail distance is.
+#define DUAL_AXIS_HOMING_FAIL_AXIS_LENGTH_PERCENT  5.0  // Float (percent)
+#define DUAL_AXIS_HOMING_FAIL_DISTANCE_MAX  25.0  // Float (mm)
+#define DUAL_AXIS_HOMING_FAIL_DISTANCE_MIN  2.5  // Float (mm)
+
+// Dual axis pin configuration currently supports two shields. Uncomment the shield you want,
+// and comment out the other one(s).
+// NOTE: Protoneer CNC Shield v3.51 has A.STP and A.DIR wired to pins A4 and A3 respectively.
+// The variable spindle (i.e. laser mode) build option works and may be enabled or disabled.
+// Coolant pin A3 is moved to D13, replacing spindle direction.
+#define DUAL_AXIS_CONFIG_PROTONEER_V3_51    // Uncomment to select. Comment other configs.
+
+// NOTE: Arduino CNC Shield Clone (Originally Protoneer v3.0) has A.STP and A.DIR wired to 
+// D12 and D13, respectively. With the limit pins and stepper enable pin on this same port,
+// the spindle enable pin had to be moved and spindle direction pin deleted. The spindle
+// enable pin now resides on A3, replacing coolant enable. Coolant enable is bumped over to
+// pin A4. Spindle enable is used far more and this pin setup helps facilitate users to 
+// integrate this feature without arguably too much work. 
+// Variable spindle (i.e. laser mode) does NOT work with this shield as configured. While
+// variable spindle technically can work with this shield, it requires too many changes for
+// most user setups to accomodate. It would best be implemented by sharing all limit switches
+// on pins D9/D10 (as [X1,Z]/[X2,Y] or [X,Y2]/[Y1,Z]), home each axis independently, and 
+// updating lots of code to ensure everything is running correctly.
+// #define DUAL_AXIS_CONFIG_CNC_SHIELD_CLONE  // Uncomment to select. Comment other configs.
+
 
 /* ---------------------------------------------------------------------------------------
    OEM Single File Configuration Option

grbl/cpu_map.h

@@ -67,39 +67,13 @@
   #else
     #define Z_LIMIT_BIT    3  // Uno Digital Pin 11
   #endif
-  #define LIMIT_MASK       ((1<<X_LIMIT_BIT)|(1<<Y_LIMIT_BIT)|(1<<Z_LIMIT_BIT)) // All limit bits
+  #if !defined(ENABLE_DUAL_AXIS)
+    #define LIMIT_MASK     ((1<<X_LIMIT_BIT)|(1<<Y_LIMIT_BIT)|(1<<Z_LIMIT_BIT)) // All limit bits
+  #endif
   #define LIMIT_INT        PCIE0  // Pin change interrupt enable pin
   #define LIMIT_INT_vect   PCINT0_vect
   #define LIMIT_PCMSK      PCMSK0 // Pin change interrupt register
 
-  // Define spindle enable and spindle direction output pins.
-  #define SPINDLE_ENABLE_DDR    DDRB
-  #define SPINDLE_ENABLE_PORT   PORTB
-  // Z Limit pin and spindle PWM/enable pin swapped to access hardware PWM on Pin 11.
-  #ifdef VARIABLE_SPINDLE
-    #ifdef USE_SPINDLE_DIR_AS_ENABLE_PIN
-      // If enabled, spindle direction pin now used as spindle enable, while PWM remains on D11.
-      #define SPINDLE_ENABLE_BIT    5  // Uno Digital Pin 13 (NOTE: D13 can't be pulled-high input due to LED.)
-    #else
-      #define SPINDLE_ENABLE_BIT    3  // Uno Digital Pin 11
-    #endif
-  #else
-    #define SPINDLE_ENABLE_BIT    4  // Uno Digital Pin 12
-  #endif
-  #ifndef USE_SPINDLE_DIR_AS_ENABLE_PIN
-    #define SPINDLE_DIRECTION_DDR   DDRB
-    #define SPINDLE_DIRECTION_PORT  PORTB
-    #define SPINDLE_DIRECTION_BIT   5  // Uno Digital Pin 13 (NOTE: D13 can't be pulled-high input due to LED.)
-  #endif
-
-  // Define flood and mist coolant enable output pins.
-  #define COOLANT_FLOOD_DDR   DDRC
-  #define COOLANT_FLOOD_PORT  PORTC
-  #define COOLANT_FLOOD_BIT   3  // Uno Analog Pin 3
-  #define COOLANT_MIST_DDR   DDRC
-  #define COOLANT_MIST_PORT  PORTC
-  #define COOLANT_MIST_BIT   4  // Uno Analog Pin 4
-
   // Define user-control controls (cycle start, reset, feed hold) input pins.
   // NOTE: All CONTROLs pins must be on the same port and not on a port with other input pins (limits).
   #define CONTROL_DDR       DDRC
@@ -122,30 +96,156 @@
   #define PROBE_BIT       5  // Uno Analog Pin 5
   #define PROBE_MASK      (1<<PROBE_BIT)
 
-  // Variable spindle configuration below. Do not change unless you know what you are doing.
-  // NOTE: Only used when variable spindle is enabled.
-  #define SPINDLE_PWM_MAX_VALUE     255 // Don't change. 328p fast PWM mode fixes top value as 255.
-  #ifndef SPINDLE_PWM_MIN_VALUE
-    #define SPINDLE_PWM_MIN_VALUE   1   // Must be greater than zero.
+  #if !defined(ENABLE_DUAL_AXIS)
+
+    // Define flood and mist coolant enable output pins.
+    #define COOLANT_FLOOD_DDR   DDRC
+    #define COOLANT_FLOOD_PORT  PORTC
+    #define COOLANT_FLOOD_BIT   3  // Uno Analog Pin 3
+    #define COOLANT_MIST_DDR   DDRC
+    #define COOLANT_MIST_PORT  PORTC
+    #define COOLANT_MIST_BIT   4  // Uno Analog Pin 4
+
+    // Define spindle enable and spindle direction output pins.
+    #define SPINDLE_ENABLE_DDR    DDRB
+    #define SPINDLE_ENABLE_PORT   PORTB
+    // Z Limit pin and spindle PWM/enable pin swapped to access hardware PWM on Pin 11.
+    #ifdef VARIABLE_SPINDLE
+      #ifdef USE_SPINDLE_DIR_AS_ENABLE_PIN
+        // If enabled, spindle direction pin now used as spindle enable, while PWM remains on D11.
+        #define SPINDLE_ENABLE_BIT    5  // Uno Digital Pin 13 (NOTE: D13 can't be pulled-high input due to LED.)
+      #else
+        #define SPINDLE_ENABLE_BIT    3  // Uno Digital Pin 11
+      #endif
+    #else
+      #define SPINDLE_ENABLE_BIT    4  // Uno Digital Pin 12
+    #endif
+    #ifndef USE_SPINDLE_DIR_AS_ENABLE_PIN
+      #define SPINDLE_DIRECTION_DDR   DDRB
+      #define SPINDLE_DIRECTION_PORT  PORTB
+      #define SPINDLE_DIRECTION_BIT   5  // Uno Digital Pin 13 (NOTE: D13 can't be pulled-high input due to LED.)
+    #endif
+
+    // Variable spindle configuration below. Do not change unless you know what you are doing.
+    // NOTE: Only used when variable spindle is enabled.
+    #define SPINDLE_PWM_MAX_VALUE     255 // Don't change. 328p fast PWM mode fixes top value as 255.
+    #ifndef SPINDLE_PWM_MIN_VALUE
+      #define SPINDLE_PWM_MIN_VALUE   1   // Must be greater than zero.
+    #endif
+    #define SPINDLE_PWM_OFF_VALUE     0
+    #define SPINDLE_PWM_RANGE         (SPINDLE_PWM_MAX_VALUE-SPINDLE_PWM_MIN_VALUE)
+    #define SPINDLE_TCCRA_REGISTER    TCCR2A
+    #define SPINDLE_TCCRB_REGISTER    TCCR2B
+    #define SPINDLE_OCR_REGISTER      OCR2A
+    #define SPINDLE_COMB_BIT          COM2A1
+
+    // Prescaled, 8-bit Fast PWM mode.
+    #define SPINDLE_TCCRA_INIT_MASK   ((1<<WGM20) | (1<<WGM21))  // Configures fast PWM mode.
+    // #define SPINDLE_TCCRB_INIT_MASK   (1<<CS20)               // Disable prescaler -> 62.5kHz
+    // #define SPINDLE_TCCRB_INIT_MASK   (1<<CS21)               // 1/8 prescaler -> 7.8kHz (Used in v0.9)
+    // #define SPINDLE_TCCRB_INIT_MASK   ((1<<CS21) | (1<<CS20)) // 1/32 prescaler -> 1.96kHz
+    #define SPINDLE_TCCRB_INIT_MASK      (1<<CS22)               // 1/64 prescaler -> 0.98kHz (J-tech laser)
+
+    // NOTE: On the 328p, these must be the same as the SPINDLE_ENABLE settings.
+    #define SPINDLE_PWM_DDR   DDRB
+    #define SPINDLE_PWM_PORT  PORTB
+    #define SPINDLE_PWM_BIT   3    // Uno Digital Pin 11
+
+  #else
+
+    // Dual axis feature requires an independent step pulse pin to operate. The independent direction pin is not 
+    // absolutely necessary but facilitates easy direction inverting with a Grbl $$ setting. These pins replace 
+    // the spindle direction and optional coolant mist pins.
+
+    #ifdef DUAL_AXIS_CONFIG_PROTONEER_V3_51
+      // NOTE: Step pulse and direction pins may be on any port and output pin.
+      #define STEP_DDR_DUAL       DDRC
+      #define STEP_PORT_DUAL      PORTC
+      #define DUAL_STEP_BIT       4  // Uno Analog Pin 4
+      #define STEP_MASK_DUAL      ((1<<DUAL_STEP_BIT))
+      #define DIRECTION_DDR_DUAL  DDRC
+      #define DIRECTION_PORT_DUAL PORTC
+      #define DUAL_DIRECTION_BIT  3  // Uno Analog Pin 3
+      #define DIRECTION_MASK_DUAL ((1<<DUAL_DIRECTION_BIT))
+
+      // NOTE: Dual axis limit is shared with the z-axis limit pin by default. Pin used must be on the same port
+      // as other limit pins.
+      #define DUAL_LIMIT_BIT    Z_LIMIT_BIT
+      #define LIMIT_MASK        ((1<<X_LIMIT_BIT)|(1<<Y_LIMIT_BIT)|(1<<Z_LIMIT_BIT)|(1<<DUAL_LIMIT_BIT))
+
+      // Define coolant enable output pins.
+      // NOTE: Coolant flood moved from A3 to A4. Coolant mist not supported with dual axis feature on Arduino Uno.
+      #define COOLANT_FLOOD_DDR   DDRB
+      #define COOLANT_FLOOD_PORT  PORTB
+      #define COOLANT_FLOOD_BIT   5  // Uno Digital Pin 13
+
+      // Define spindle enable output pin.
+      // NOTE: Spindle enable moved from D12 to A3 (old coolant flood enable pin). Spindle direction pin is removed.
+      #define SPINDLE_ENABLE_DDR    DDRB
+      #define SPINDLE_ENABLE_PORT   PORTB
+      #ifdef VARIABLE_SPINDLE
+        // NOTE: USE_SPINDLE_DIR_AS_ENABLE_PIN not supported with dual axis feature.
+        #define SPINDLE_ENABLE_BIT    3  // Uno Digital Pin 11
+      #else
+        #define SPINDLE_ENABLE_BIT    4  // Uno Digital Pin 12
+      #endif
+
+      // Variable spindle configuration below. Do not change unless you know what you are doing.
+      // NOTE: Only used when variable spindle is enabled.
+      #define SPINDLE_PWM_MAX_VALUE     255 // Don't change. 328p fast PWM mode fixes top value as 255.
+      #ifndef SPINDLE_PWM_MIN_VALUE
+        #define SPINDLE_PWM_MIN_VALUE   1   // Must be greater than zero.
+      #endif
+      #define SPINDLE_PWM_OFF_VALUE     0
+      #define SPINDLE_PWM_RANGE         (SPINDLE_PWM_MAX_VALUE-SPINDLE_PWM_MIN_VALUE)
+      #define SPINDLE_TCCRA_REGISTER    TCCR2A
+      #define SPINDLE_TCCRB_REGISTER    TCCR2B
+      #define SPINDLE_OCR_REGISTER      OCR2A
+      #define SPINDLE_COMB_BIT          COM2A1
+
+      // Prescaled, 8-bit Fast PWM mode.
+      #define SPINDLE_TCCRA_INIT_MASK   ((1<<WGM20) | (1<<WGM21))  // Configures fast PWM mode.
+      // #define SPINDLE_TCCRB_INIT_MASK   (1<<CS20)               // Disable prescaler -> 62.5kHz
+      // #define SPINDLE_TCCRB_INIT_MASK   (1<<CS21)               // 1/8 prescaler -> 7.8kHz (Used in v0.9)
+      // #define SPINDLE_TCCRB_INIT_MASK   ((1<<CS21) | (1<<CS20)) // 1/32 prescaler -> 1.96kHz
+      #define SPINDLE_TCCRB_INIT_MASK      (1<<CS22)               // 1/64 prescaler -> 0.98kHz (J-tech laser)
+
+      // NOTE: On the 328p, these must be the same as the SPINDLE_ENABLE settings.
+      #define SPINDLE_PWM_DDR   DDRB
+      #define SPINDLE_PWM_PORT  PORTB
+      #define SPINDLE_PWM_BIT   3    // Uno Digital Pin 11
+    #endif
+
+    // NOTE: Variable spindle not supported with this shield.
+    #ifdef DUAL_AXIS_CONFIG_CNC_SHIELD_CLONE
+      // NOTE: Step pulse and direction pins may be on any port and output pin.
+      #define STEP_DDR_DUAL       DDRB
+      #define STEP_PORT_DUAL      PORTB
+      #define DUAL_STEP_BIT       4  // Uno Digital Pin 12
+      #define STEP_MASK_DUAL      ((1<<DUAL_STEP_BIT))
+      #define DIRECTION_DDR_DUAL  DDRB
+      #define DIRECTION_PORT_DUAL PORTB
+      #define DUAL_DIRECTION_BIT  5  // Uno Digital Pin 13
+      #define DIRECTION_MASK_DUAL ((1<<DUAL_DIRECTION_BIT))
+
+      // NOTE: Dual axis limit is shared with the z-axis limit pin by default.
+      #define DUAL_LIMIT_BIT    Z_LIMIT_BIT
+      #define LIMIT_MASK        ((1<<X_LIMIT_BIT)|(1<<Y_LIMIT_BIT)|(1<<Z_LIMIT_BIT)|(1<<DUAL_LIMIT_BIT))
+
+      // Define coolant enable output pins.
+      // NOTE: Coolant flood moved from A3 to A4. Coolant mist not supported with dual axis feature on Arduino Uno.
+      #define COOLANT_FLOOD_DDR   DDRC
+      #define COOLANT_FLOOD_PORT  PORTC
+      #define COOLANT_FLOOD_BIT   4  // Uno Analog Pin 4
+
+      // Define spindle enable output pin.
+      // NOTE: Spindle enable moved from D12 to A3 (old coolant flood enable pin). Spindle direction pin is removed.
+      #define SPINDLE_ENABLE_DDR    DDRC
+      #define SPINDLE_ENABLE_PORT   PORTC
+      #define SPINDLE_ENABLE_BIT    3  // Uno Analog Pin 3
+    #endif
+
   #endif
-  #define SPINDLE_PWM_OFF_VALUE     0
-  #define SPINDLE_PWM_RANGE         (SPINDLE_PWM_MAX_VALUE-SPINDLE_PWM_MIN_VALUE)
-  #define SPINDLE_TCCRA_REGISTER	  TCCR2A
-  #define SPINDLE_TCCRB_REGISTER	  TCCR2B
-  #define SPINDLE_OCR_REGISTER      OCR2A
-  #define SPINDLE_COMB_BIT	        COM2A1
-
-  // Prescaled, 8-bit Fast PWM mode.
-  #define SPINDLE_TCCRA_INIT_MASK   ((1<<WGM20) | (1<<WGM21))  // Configures fast PWM mode.
-  // #define SPINDLE_TCCRB_INIT_MASK   (1<<CS20)               // Disable prescaler -> 62.5kHz
-  // #define SPINDLE_TCCRB_INIT_MASK   (1<<CS21)               // 1/8 prescaler -> 7.8kHz (Used in v0.9)
-  // #define SPINDLE_TCCRB_INIT_MASK   ((1<<CS21) | (1<<CS20)) // 1/32 prescaler -> 1.96kHz
-  #define SPINDLE_TCCRB_INIT_MASK      (1<<CS22)               // 1/64 prescaler -> 0.98kHz (J-tech laser)
-
-  // NOTE: On the 328p, these must be the same as the SPINDLE_ENABLE settings.
-  #define SPINDLE_PWM_DDR	  DDRB
-  #define SPINDLE_PWM_PORT  PORTB
-  #define SPINDLE_PWM_BIT	  3    // Uno Digital Pin 11
 
 #endif