G38.2 probe feature rough draft installed. Working but needs testing.

- G38.2 straight probe now supported. Rough draft. May be tweaked more
as testing ramps up.

- G38.2 requires at least one axis word. Multiple axis words work too.
When commanded, the probe cycle will move at the last ‘F’ feed rate
specified in a straight line.

- During a probe cycle: If the probe pin goes low (normal high), Grbl
will record that immediate position and engage a feed hold. Meaning
that the CNC machine will move a little past the probe switch point, so
keep federates low to stop sooner. Once stopped, Grbl will issue a move
to go back to the recorded probe trigger point.

- During a probe cycle: If the probe switch does not engage by the time
the machine has traveled to its target coordinates, Grbl will issue an
ALARM and the user will be forced to reset Grbl. (Currently G38.3 probe
without error isn’t supported, but would be easy to implement later.)

- After a successful probe, Grbl will send a feedback message
containing the recorded probe coordinates in the machine coordinate
system. This is as the g-code standard on probe parameters specifies.

- The recorded probe parameters are retained in Grbl memory and can be
viewed with the ‘$#’ print parameters command. Upon a power-cycle, not
a soft-reset, Grbl will re-zero these values.

- Moved ‘$#’ command to require IDLE or ALARM mode, because it accesses
EEPROM to fetch the coordinate system offsets.

- Updated the Grbl version to v0.9d.

- The probe cycle is subject to change upon testing or user-feedback.

report.c

@@ -79,8 +79,6 @@ void report_status_message(uint8_t status_code)
       printPgmString(PSTR("Homing not enabled")); break;
       case STATUS_OVERFLOW:
       printPgmString(PSTR("Line overflow")); break; 
-      case STATUS_PROBE_ERROR:
-      printPgmString(PSTR("Probe error")); break; 
     }
     printPgmString(PSTR("\r\n"));
   }
@@ -95,8 +93,10 @@ void report_alarm_message(int8_t alarm_code)
     printPgmString(PSTR("Hard/soft limit")); break;
     case ALARM_ABORT_CYCLE: 
     printPgmString(PSTR("Abort during cycle")); break;
+    case ALARM_PROBE_FAIL:
+    printPgmString(PSTR("Probe fail")); break;
   }
-  printPgmString(PSTR(". MPos?\r\n"));
+  printPgmString(PSTR("\r\n"));
   delay_ms(500); // Force delay to ensure message clears serial write buffer.
 }
 
@@ -190,8 +190,28 @@ void report_grbl_settings() {
 }
 
 
-// Prints gcode coordinate offset parameters
-void report_gcode_parameters()
+// Prints current probe parameters. Upon a probe command, these parameters are updated upon a
+// successful probe or upon a failed probe with the G38.3 without errors command (if supported). 
+// These values are retained until Grbl is power-cycled, whereby they will be re-zeroed.
+void report_probe_parameters()
+{
+  uint8_t i;
+  float print_position[N_AXIS];
+ 
+  // Report in terms of machine position.
+  printPgmString(PSTR("[Probe:")); 
+  for (i=0; i< N_AXIS; i++) {
+    print_position[i] = sys.probe_position[i]/settings.steps_per_mm[i];
+    if (bit_istrue(settings.flags,BITFLAG_REPORT_INCHES)) { print_position[i] *= INCH_PER_MM; }
+    printFloat(print_position[i]);
+    if (i < (N_AXIS-1)) { printPgmString(PSTR(",")); }
+  }  
+  printPgmString(PSTR("]\r\n"));
+}
+
+
+// Prints Grbl NGC parameters (coordinate offsets, probing)
+void report_ngc_parameters()
 {
   float coord_data[N_AXIS];
   uint8_t coord_select, i;
@@ -226,6 +246,7 @@ void report_gcode_parameters()
     if (i < (N_AXIS-1)) { printPgmString(PSTR(",")); }
     else { printPgmString(PSTR("]\r\n")); }
   } 
+  report_probe_parameters(); // Print probe parameters. Not persistent in memory.
 }
 
 
@@ -353,7 +374,7 @@ void report_realtime_status()
     if (i < (N_AXIS-1)) { printPgmString(PSTR(",")); }
   }
     
-#ifdef USE_LINE_NUMBERS
+  #ifdef USE_LINE_NUMBERS
   // Report current line number
   printPgmString(PSTR(",Ln:")); 
   int32_t ln=0;
@@ -362,56 +383,7 @@ void report_realtime_status()
     ln = pb->line_number;
   } 
   printInteger(ln);
-#endif
-    
-  printPgmString(PSTR(">\r\n"));
-}
-
-// Prints real-time data. This function grabs a real-time snapshot of the stepper subprogram 
- // and the actual location of the CNC machine. Users may change the following function to their
- // specific needs.  It is kept separate from the "normal" report_realtime_status() to allow customization. 
-void report_realtime_status_probe()
-{
-  // **Under construction** Bare-bones status report. Provides real-time machine position relative to 
-  // the system power on location (0,0,0) and work coordinate position (G54 and G92 applied). 
-  uint8_t i;
-  int32_t current_position[N_AXIS]; // Copy current state of the system position variable
-  memcpy(current_position,sys.position,sizeof(sys.position));
-  float print_position[N_AXIS];
- 
-  printPgmString(PSTR("<Probe")); 
-
-  // Report machine position
-  printPgmString(PSTR(",MPos:")); 
-  for (i=0; i< N_AXIS; i++) {
-    print_position[i] = current_position[i]/settings.steps_per_mm[i];
-    if (bit_istrue(settings.flags,BITFLAG_REPORT_INCHES)) { print_position[i] *= INCH_PER_MM; }
-    printFloat(print_position[i]);
-    printPgmString(PSTR(","));
-  }
-  
-  // Report work position
-  printPgmString(PSTR("WPos:")); 
-  for (i=0; i< N_AXIS; i++) {
-    if (bit_istrue(settings.flags,BITFLAG_REPORT_INCHES)) {
-      print_position[i] -= (gc.coord_system[i]+gc.coord_offset[i])*INCH_PER_MM;
-    } else {
-      print_position[i] -= gc.coord_system[i]+gc.coord_offset[i];
-    }
-    printFloat(print_position[i]);
-    if (i < (N_AXIS-1)) { printPgmString(PSTR(",")); }
-  }
-    
-#ifdef USE_LINE_NUMBERS
-  // Report current line number
-  printPgmString(PSTR(",Ln:")); 
-  int32_t ln=0;
-  plan_block_t * pb = plan_get_current_block();
-  if(pb != NULL) {
-    ln = pb->line_number;
-  } 
-  printInteger(ln);
-#endif
+  #endif
     
   printPgmString(PSTR(">\r\n"));
 }