From 85b0c7a8b48e68fe0c4a5e8b2d8cb24a0789a231 Mon Sep 17 00:00:00 2001
From: Sonny Jeon <chamnit@gmail.com>
Date: Wed, 25 Feb 2015 08:29:56 -0700
Subject: [PATCH] G91.1 support. Fixed a config.h option.
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- G91.1 support added. This g-code sets the arc IJK distance mode to
incremental, which is the default already. This simply  helps reduce
parsing errors with certain CAM programs that output this command.

- Max step rate checks weren’t being compiled in if the option was
enabled. Fixed now.

- Alarm codes were not displaying correctly when GUI reporting mode was
enabled. Due to unsigned int problem. Changed codes to positive values
since they aren’t shared with other codes.
---
 README.md       |  1 +
 grbl/gcode.c    | 13 ++++++++++---
 grbl/gcode.h    | 20 ++++++++++++--------
 grbl/report.c   |  9 +++++----
 grbl/report.h   | 14 +++++++-------
 grbl/settings.c |  8 ++++++--
 6 files changed, 41 insertions(+), 24 deletions(-)

diff --git a/README.md b/README.md
index 3e69e23..962d932 100644
--- a/README.md
+++ b/README.md
@@ -69,6 +69,7 @@ List of Supported G-Codes in Grbl v0.9
   - Feed Rate Modes: G93, G94
   - Unit Modes: G20, G21
   - Distance Modes: G90, G91
+  - Arc IJK Distance Modes: G91.1
   - Plane Select Modes: G17, G18, G19
   - Tool Length Offset Modes: G43.1, G49
   - Cutter Compensation Modes: G40
diff --git a/grbl/gcode.c b/grbl/gcode.c
index b915e48..37f9ff9 100644
--- a/grbl/gcode.c
+++ b/grbl/gcode.c
@@ -213,9 +213,16 @@ uint8_t gc_execute_line(char *line)
             }
             break;
           case 90: case 91: 
-            word_bit = MODAL_GROUP_G3; 
-            if (int_value == 90) { gc_block.modal.distance = DISTANCE_MODE_ABSOLUTE; } // G90
-            else { gc_block.modal.distance = DISTANCE_MODE_INCREMENTAL; } // G91            
+            if (mantissa == 0) {
+              word_bit = MODAL_GROUP_G3; 
+              if (int_value == 90) { gc_block.modal.distance = DISTANCE_MODE_ABSOLUTE; } // G90
+              else { gc_block.modal.distance = DISTANCE_MODE_INCREMENTAL; } // G91
+            } else {
+              word_bit = MODAL_GROUP_G4;
+              if (mantissa != 10) { FAIL(STATUS_GCODE_UNSUPPORTED_COMMAND); } // [G90.1 not supported]
+              mantissa = 0; // Set to zero to indicate valid non-integer G command.
+              // Otherwise, arc IJK incremental mode is default. G91.1 does nothing.
+            }
             break;
           case 93: case 94: 
             word_bit = MODAL_GROUP_G5; 
diff --git a/grbl/gcode.h b/grbl/gcode.h
index 0b478d0..46df351 100644
--- a/grbl/gcode.h
+++ b/grbl/gcode.h
@@ -33,15 +33,16 @@
 #define MODAL_GROUP_G1 1 // [G0,G1,G2,G3,G38.2,G80] Motion
 #define MODAL_GROUP_G2 2 // [G17,G18,G19] Plane selection
 #define MODAL_GROUP_G3 3 // [G90,G91] Distance mode
-#define MODAL_GROUP_G5 4 // [G93,G94] Feed rate mode
-#define MODAL_GROUP_G6 5 // [G20,G21] Units
-#define MODAL_GROUP_G7 6 // [G40] Cutter radius compensation mode. G41/42 NOT SUPPORTED.
-#define MODAL_GROUP_G8 7 // [G43,G43.1,G49] Tool length offset
-#define MODAL_GROUP_G12 8 // [G54,G55,G56,G57,G58,G59] Coordinate system selection
+#define MODAL_GROUP_G4 4 // [G90.1,G91.1] Arc IJK distance mode
+#define MODAL_GROUP_G5 5 // [G93,G94] Feed rate mode
+#define MODAL_GROUP_G6 6 // [G20,G21] Units
+#define MODAL_GROUP_G7 7 // [G40] Cutter radius compensation mode. G41/42 NOT SUPPORTED.
+#define MODAL_GROUP_G8 8 // [G43,G43.1,G49] Tool length offset
+#define MODAL_GROUP_G12 9 // [G54,G55,G56,G57,G58,G59] Coordinate system selection
 
-#define MODAL_GROUP_M4 9  // [M0,M1,M2,M30] Stopping
-#define MODAL_GROUP_M7 10 // [M3,M4,M5] Spindle turning
-#define MODAL_GROUP_M8 11 // [M7,M8,M9] Coolant control
+#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 OTHER_INPUT_F 12
 #define OTHER_INPUT_S 13
@@ -82,6 +83,9 @@
 #define DISTANCE_MODE_ABSOLUTE 0 // G90 (Default: Must be zero)
 #define DISTANCE_MODE_INCREMENTAL 1 // G91
 
+// Modal Group G4: Arc IJK distance mode
+#define DISTANCE_ARC_MODE_INCREMENTAL 0 // G91.1 (Default: Must be zero)
+
 // Modal Group M4: Program flow
 #define PROGRAM_FLOW_RUNNING 0 // (Default: Must be zero)
 #define PROGRAM_FLOW_PAUSED 1 // M0, M1
diff --git a/grbl/report.c b/grbl/report.c
index eae6995..9460f6a 100644
--- a/grbl/report.c
+++ b/grbl/report.c
@@ -68,10 +68,11 @@ void report_status_message(uint8_t status_code)
         case STATUS_SOFT_LIMIT_ERROR:
         printPgmString(PSTR("Homing not enabled")); break;
         case STATUS_OVERFLOW:
-        printPgmString(PSTR("Line overflow")); break; 
-        // case STATUS_MAX_STEP_RATE_EXCEEDED: 
-        // printPgmString(PSTR("Step rate > 30kHz")); break;
-      
+        printPgmString(PSTR("Line overflow")); break;
+        #ifdef MAX_STEP_RATE_HZ
+          case STATUS_MAX_STEP_RATE_EXCEEDED: 
+          printPgmString(PSTR("Step rate > 30kHz")); break;
+        #endif      
         // Common g-code parser errors.
         case STATUS_GCODE_MODAL_GROUP_VIOLATION:
         printPgmString(PSTR("Modal group violation")); break;
diff --git a/grbl/report.h b/grbl/report.h
index cfd0d8b..e21df42 100644
--- a/grbl/report.h
+++ b/grbl/report.h
@@ -33,7 +33,7 @@
 #define STATUS_ALARM_LOCK 9
 #define STATUS_SOFT_LIMIT_ERROR 10
 #define STATUS_OVERFLOW 11
-// #define STATUS_MAX_STEP_RATE_EXCEEDED 12
+#define STATUS_MAX_STEP_RATE_EXCEEDED 12
 
 #define STATUS_GCODE_UNSUPPORTED_COMMAND 20
 #define STATUS_GCODE_MODAL_GROUP_VIOLATION 21
@@ -54,12 +54,12 @@
 #define STATUS_GCODE_UNUSED_WORDS 36
 #define STATUS_GCODE_G43_DYNAMIC_AXIS_ERROR 37
 
-// Define Grbl alarm codes. Less than zero to distinguish alarm error from status error.
-#define ALARM_HARD_LIMIT_ERROR -1
-#define ALARM_SOFT_LIMIT_ERROR -2
-#define ALARM_ABORT_CYCLE -3
-#define ALARM_PROBE_FAIL -4
-#define ALARM_HOMING_FAIL -5
+// Define Grbl alarm codes.
+#define ALARM_HARD_LIMIT_ERROR 1
+#define ALARM_SOFT_LIMIT_ERROR 2
+#define ALARM_ABORT_CYCLE 3
+#define ALARM_PROBE_FAIL 4
+#define ALARM_HOMING_FAIL 5
 
 // Define Grbl feedback message codes.
 #define MESSAGE_CRITICAL_EVENT 1
diff --git a/grbl/settings.c b/grbl/settings.c
index 956cb02..87535d5 100644
--- a/grbl/settings.c
+++ b/grbl/settings.c
@@ -189,11 +189,15 @@ uint8_t settings_store_global_setting(uint8_t parameter, float value) {
         // Valid axis setting found.
         switch (set_idx) {
           case 0:
-            // if (value*settings.max_rate[parameter] > (MAX_STEP_RATE_HZ*60.0)) { return(STATUS_MAX_STEP_RATE_EXCEEDED); }
+            #ifdef MAX_STEP_RATE_HZ
+              if (value*settings.max_rate[parameter] > (MAX_STEP_RATE_HZ*60.0)) { return(STATUS_MAX_STEP_RATE_EXCEEDED); }
+            #endif
             settings.steps_per_mm[parameter] = value;
             break;
           case 1:
-            // if (value*settings.steps_per_mm[parameter] > (MAX_STEP_RATE_HZ*60.0)) {  return(STATUS_MAX_STEP_RATE_EXCEEDED); }
+            #ifdef MAX_STEP_RATE_HZ
+              if (value*settings.steps_per_mm[parameter] > (MAX_STEP_RATE_HZ*60.0)) {  return(STATUS_MAX_STEP_RATE_EXCEEDED); }
+            #endif
             settings.max_rate[parameter] = value;
             break;
           case 2: settings.acceleration[parameter] = value*60*60; break; // Convert to mm/min^2 for grbl internal use.