Added coolant control (M7*, M8, M9). Mist control can be enabled via config.h.

- Added coolant control! Flood control (M8) functions on analog pin 0.
Mist control (M7) is compile-time optional and is on analog pin 1. (Use
only if you have multiple coolants on your system). Based on work by
@openpnp.

- Fixed some variable assignments in spindle control.

Makefile

@@ -30,8 +30,8 @@
 DEVICE     ?= atmega328p
 CLOCK      = 16000000
 PROGRAMMER ?= -c avrisp2 -P usb
-OBJECTS    = main.o motion_control.o gcode.o spindle_control.o serial.o protocol.o stepper.o \
-             eeprom.o settings.o planner.o nuts_bolts.o limits.o print.o
+OBJECTS    = main.o motion_control.o gcode.o spindle_control.o coolant_control.o serial.o \
+             protocol.o stepper.o eeprom.o settings.o planner.o nuts_bolts.o limits.o print.o
 # FUSES      = -U hfuse:w:0xd9:m -U lfuse:w:0x24:m
 FUSES      = -U hfuse:w:0xd2:m -U lfuse:w:0xff:m
 # update that line with this when programmer is back up:

config.h

@@ -54,6 +54,18 @@
 #define SPINDLE_DIRECTION_PORT PORTB
 #define SPINDLE_DIRECTION_BIT 5  // Uno Digital Pin 13
 
+#define COOLANT_FLOOD_DDR   DDRC
+#define COOLANT_FLOOD_PORT   PORTC
+#define COOLANT_FLOOD_BIT  0  // Uno Analog Pin 0
+
+#define ENABLE_M7 0 // DISABLED BY DEFAULT: To enable, change to '1' and recompile.
+#if ENABLE_M7
+  #define COOLANT_MIST_DDR   DDRC
+  #define COOLANT_MIST_PORT   PORTC
+  #define COOLANT_MIST_BIT  1 // Uno Analog Pin 1
+#endif  
+
+
 // Define runtime command special characters. These characters are 'picked-off' directly from the
 // serial read data stream and are not passed to the grbl line execution parser. Select characters
 // that do not and must not exist in the streamed g-code program. ASCII control characters may be 

coolant_control.c

@@ -0,0 +1,65 @@
+/*
+  coolant_control.c - coolant control methods
+  Part of Grbl
+
+  Copyright (c) 2012 Sungeun K. Jeon
+
+  Grbl 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.
+
+  Grbl 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 Grbl.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "coolant_control.h"
+#include "settings.h"
+#include "config.h"
+#include "planner.h"
+
+#include <avr/io.h>
+
+static uint8_t current_coolant_mode;
+
+void coolant_init()
+{
+  current_coolant_mode = COOLANT_DISABLE;
+  #if ENABLE_M7
+    COOLANT_MIST_DDR |= (1 << COOLANT_MIST_BIT);
+  #endif
+  COOLANT_FLOOD_DDR |= (1 << COOLANT_FLOOD_BIT);
+  coolant_stop();
+}
+
+void coolant_stop()
+{
+  #if ENABLE_M7
+    COOLANT_MIST_PORT &= ~(1 << COOLANT_MIST_BIT);
+  #endif
+  COOLANT_FLOOD_PORT &= ~(1 << COOLANT_FLOOD_BIT);
+}
+
+
+void coolant_run(uint8_t mode)
+{
+  if (mode != current_coolant_mode)
+  { 
+    plan_synchronize(); // Ensure coolant turns on when specified in program.
+    if (mode == COOLANT_FLOOD_ENABLE) { 
+      COOLANT_FLOOD_PORT |= (1 << COOLANT_FLOOD_BIT);
+    #if ENABLE_M7  
+      } else if (mode == COOLANT_MIST_ENABLE) {
+          COOLANT_MIST_PORT |= (1 << COOLANT_MIST_BIT);
+    #endif
+    } else {
+      coolant_stop();
+    }
+    current_coolant_mode = mode;
+  }
+}

coolant_control.h

@@ -0,0 +1,34 @@
+/*
+  coolant_control.h - spindle control methods
+  Part of Grbl
+
+  Copyright (c) 2012 Sungeun K. Jeon
+
+  Grbl 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.
+
+  Grbl 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 Grbl.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef coolant_control_h
+#define coolant_control_h 
+
+#include <avr/io.h>
+
+#define COOLANT_MIST_ENABLE 2
+#define COOLANT_FLOOD_ENABLE 1
+#define COOLANT_DISABLE 0 // Must be zero.
+
+void coolant_init();
+void coolant_stop();
+void coolant_run(uint8_t mode);
+
+#endif

gcode.c

@@ -29,6 +29,7 @@
 #include "settings.h"
 #include "motion_control.h"
 #include "spindle_control.h"
+#include "coolant_control.h"
 #include "errno.h"
 #include "protocol.h"
 
@@ -75,10 +76,11 @@ typedef struct {
   uint8_t absolute_mode;           // 0 = relative motion, 1 = absolute motion {G90, G91}
   uint8_t program_flow;            // {M0, M1, M2, M30}
   int8_t spindle_direction;        // 1 = CW, -1 = CCW, 0 = Stop {M3, M4, M5}
+  uint8_t coolant_mode;            // 0 = Disable, 1 = Flood Enable {M8, M9}
   double feed_rate, seek_rate;     // Millimeters/second
   double position[3];              // Where the interpreter considers the tool to be at this point in the code
   uint8_t tool;
-  int16_t spindle_speed;           // RPM/100
+  uint16_t spindle_speed;          // RPM/100
   uint8_t plane_axis_0, 
           plane_axis_1, 
           plane_axis_2;            // The axes of the selected plane  
@@ -214,6 +216,11 @@ uint8_t gc_execute_line(char *line)
           case 3: gc.spindle_direction = 1; break;
           case 4: gc.spindle_direction = -1; break;
           case 5: gc.spindle_direction = 0; break;
+          #if ENABLE_M7
+            case 7: gc.coolant_mode = COOLANT_MIST_ENABLE; break;
+          #endif
+          case 8: gc.coolant_mode = COOLANT_FLOOD_ENABLE; break;
+          case 9: gc.coolant_mode = COOLANT_DISABLE; break;
           default: FAIL(STATUS_UNSUPPORTED_STATEMENT);
         }            
         break;
@@ -279,7 +286,8 @@ uint8_t gc_execute_line(char *line)
   // [M3,M4,M5]: Update spindle state
   spindle_run(gc.spindle_direction, gc.spindle_speed);
   
-  //  ([M7,M8,M9]: Coolant state should be executed here.)
+  // [*M7,M8,M9]: Update coolant state
+  coolant_run(gc.coolant_mode);
   
   // [G4,G10,G28,G30,G92,G92.1]: Perform dwell, set coordinate system data, homing, or set axis offsets.
   // NOTE: These commands are in the same modal group, hence are mutually exclusive. G53 is in this
@@ -578,7 +586,7 @@ static int next_statement(char *letter, double *double_ptr, char *line, uint8_t
    group 0 = {G92.2, G92.3} (Non modal: Cancel and re-enable G92 offsets)
    group 1 = {G38.2, G81 - G89} (Motion modes: straight probe, canned cycles)
    group 6 = {M6} (Tool change)
-   group 8 = {M7, M8, M9} coolant (special case: M7 and M8 may be active at the same time)
+   group 8 = {M7} coolant (M7 mist may be enabled via config.h)
    group 9 = {M48, M49} enable/disable feed and speed override switches
    group 12 = {G55, G56, G57, G58, G59, G59.1, G59.2, G59.3} coordinate system selection
    group 13 = {G61, G61.1, G64} path control mode

main.c

@@ -26,6 +26,7 @@
 #include "nuts_bolts.h"
 #include "stepper.h"
 #include "spindle_control.h"
+#include "coolant_control.h"
 #include "motion_control.h"
 #include "gcode.h"
 #include "protocol.h"
@@ -73,6 +74,7 @@ int main(void)
       plan_init(); // Clear block buffer and planner variables
       gc_init(); // Set g-code parser to default state
       spindle_init();
+      coolant_init();
       limits_init();
       st_reset(); // Clear stepper subsystem variables.
       

spindle_control.c

@@ -43,7 +43,7 @@ void spindle_stop()
   SPINDLE_ENABLE_PORT &= ~(1<<SPINDLE_ENABLE_BIT);
 }
 
-void spindle_run(int direction, uint32_t rpm) 
+void spindle_run(int8_t direction, uint16_t rpm) 
 {
   if (direction != current_direction) {
     plan_synchronize();

spindle_control.h

@@ -24,7 +24,7 @@
 #include <avr/io.h>
 
 void spindle_init();
-void spindle_run(int direction, uint32_t rpm);
+void spindle_run(int8_t direction, uint16_t rpm);
 void spindle_stop();
 
 #endif