Added G61 exact path support.

- G61 exact path is the Grbl default path control mode, so it’s now
added as a supported g-code.

grbl/gcode.c

@@ -259,6 +259,11 @@ uint8_t gc_execute_line(char *line)
             word_bit = MODAL_GROUP_G12;
             gc_block.modal.coord_select = int_value-54; // Shift to array indexing.
             break;
+          case 61:
+            word_bit = MODAL_GROUP_G13;
+            if (mantissa != 0) { FAIL(STATUS_GCODE_UNSUPPORTED_COMMAND); } // [G61.1 not supported]
+            // gc_block.modal.control = CONTROL_MODE_EXACT_PATH; // G61
+            break;
           default: FAIL(STATUS_GCODE_UNSUPPORTED_COMMAND); // [Unsupported G command]
         }      
         if (mantissa > 0) { FAIL(STATUS_GCODE_COMMAND_VALUE_NOT_INTEGER); } // [Unsupported or invalid Gxx.x command]
@@ -519,8 +524,8 @@ uint8_t gc_execute_line(char *line)
     }
   }
   
-  // [16. Set path control mode ]: NOT SUPPORTED.
-  // [17. Set distance mode ]: N/A. G90.1 and G91.1 NOT SUPPORTED.
+  // [16. Set path control mode ]: N/A. Only G61. G61.1 and G64 NOT SUPPORTED.
+  // [17. Set distance mode ]: N/A. Only G91.1. G90.1 NOT SUPPORTED.
   // [18. Set retract mode ]: NOT SUPPORTED.
   
   // [19. Remaining non-modal actions ]: Check go to predefined position, set G10, or set axis offsets.
@@ -900,7 +905,8 @@ uint8_t gc_execute_line(char *line)
     memcpy(gc_state.coord_system,coordinate_data,sizeof(coordinate_data));
   }
   
-  // [16. Set path control mode ]: NOT SUPPORTED
+  // [16. Set path control mode ]: G61.1/G64 NOT SUPPORTED
+  // gc_state.modal.control = gc_block.modal.control; // NOTE: Always default.
   
   // [17. Set distance mode ]:
   gc_state.modal.distance = gc_block.modal.distance;
@@ -1089,5 +1095,5 @@ uint8_t gc_execute_line(char *line)
    group 8 = {*M7} enable mist coolant (* Compile-option)
    group 9 = {M48, M49} enable/disable feed and speed override switches
    group 10 = {G98, G99} return mode canned cycles
-   group 13 = {G61, G61.1, G64} path control mode
+   group 13 = {G61.1, G64} path control mode (G61 is supported)
 */

grbl/gcode.h

@@ -39,14 +39,15 @@
 #define MODAL_GROUP_G7 7 // [G40] Cutter radius compensation mode. G41/42 NOT SUPPORTED.
 #define MODAL_GROUP_G8 8 // [G43.1,G49] Tool length offset
 #define MODAL_GROUP_G12 9 // [G54,G55,G56,G57,G58,G59] Coordinate system selection
+#define MODAL_GROUP_G13 10 // [G61] Control mode
 
-#define MODAL_GROUP_M4 10  // [M0,M1,M2,M30] Stopping
-#define MODAL_GROUP_M7 11 // [M3,M4,M5] Spindle turning
-#define MODAL_GROUP_M8 12 // [M7,M8,M9] Coolant control
+#define MODAL_GROUP_M4 11  // [M0,M1,M2,M30] Stopping
+#define MODAL_GROUP_M7 12 // [M3,M4,M5] Spindle turning
+#define MODAL_GROUP_M8 13 // [M7,M8,M9] Coolant control
 
-#define OTHER_INPUT_F 12
-#define OTHER_INPUT_S 13
-#define OTHER_INPUT_T 14
+// #define OTHER_INPUT_F 14
+// #define OTHER_INPUT_S 15
+// #define OTHER_INPUT_T 16
 
 // Define command actions for within execution-type modal groups (motion, stopping, non-modal). Used
 // internally by the parser to know which command to execute.
@@ -102,6 +103,9 @@
 // Modal Group G7: Cutter radius compensation mode
 #define CUTTER_COMP_DISABLE 0 // G40 (Default: Must be zero)
 
+// Modal Group G13: Control mode
+#define CONTROL_MODE_EXACT_PATH 0 // G61 (Default: Must be zero)
+
 // Modal Group M7: Spindle control
 #define SPINDLE_DISABLE 0 // M5 (Default: Must be zero)
 #define SPINDLE_ENABLE_CW 1 // M3
@@ -119,6 +123,8 @@
 // Modal Group G12: Active work coordinate system
 // N/A: Stores coordinate system value (54-59) to change to.
 
+
+// Define parameter word mapping.
 #define WORD_F  0
 #define WORD_I  1
 #define WORD_J  2
@@ -134,19 +140,18 @@
 #define WORD_Z  12
 
 
-
-
 // NOTE: When this struct is zeroed, the above defines set the defaults for the system.
 typedef struct {
   uint8_t motion;          // {G0,G1,G2,G3,G38.2,G80}
   uint8_t feed_rate;       // {G93,G94}
   uint8_t units;           // {G20,G21}
   uint8_t distance;        // {G90,G91}
-  // uint8_t distance_arc; // {G91.1} NOTE: Don't track. Only one supported.
+  // uint8_t distance_arc; // {G91.1} NOTE: Don't track. Only default supported.
   uint8_t plane_select;    // {G17,G18,G19}
-  // uint8_t cutter_comp;  // {G40} NOTE: Don't track. Only one supported.
+  // uint8_t cutter_comp;  // {G40} NOTE: Don't track. Only default supported.
   uint8_t tool_length;     // {G43.1,G49}
   uint8_t coord_select;    // {G54,G55,G56,G57,G58,G59}
+  // uint8_t control;      // {G61} NOTE: Don't track. Only default supported.
   uint8_t program_flow;    // {M0,M1,M2,M30}
   uint8_t coolant;         // {M7,M8,M9}
   uint8_t spindle;         // {M3,M4,M5}

grbl/grbl.h

@@ -23,7 +23,7 @@
 
 // Grbl versioning system
 #define GRBL_VERSION "0.9i"
-#define GRBL_VERSION_BUILD "20150523"
+#define GRBL_VERSION_BUILD "20150529"
 
 // Define standard libraries used by Grbl.
 #include <avr/io.h>