$140, $141, $142 current control

README.md

@@ -21,6 +21,11 @@ Usage notes:
 * Hard limits not yet ported
 * Control inputs not yet ported (e.g. Cycle Start and Safety Door switches)
 
+New configuration settings
+* $140, $141, $142 are X, Y, Z current (amps)
+* Default to 0.0 A to avoid burning out your motors
+* Your motors will likely stall if you don't set these!
+
 Build notes:
 * Include ```make``` and the ```arm-none-eabi-*``` tools in your path.
 * Make produces 2 files:

grbl-lpc/current_control.cpp

@@ -24,6 +24,10 @@
 #include "grbl.h"
 #include "Driver_I2C.h"
 
+#undef min
+#undef max
+#include <algorithm>
+
 #ifdef CURRENT_I2C
 extern ARM_DRIVER_I2C CURRENT_I2C;
 static const uint8_t wiperRegs[] = CURRENT_WIPERS;
@@ -48,9 +52,9 @@ void current_init()
         ;
 #endif
 
-    set_current(0, DEFAULT_X_CURRENT);
-    set_current(1, DEFAULT_Y_CURRENT);
-    set_current(2, DEFAULT_Z_CURRENT);
+    set_current(0, settings.current[0]);
+    set_current(1, settings.current[1]);
+    set_current(2, settings.current[2]);
     set_current(3, DEFAULT_A_CURRENT);
 #endif
 }
@@ -60,7 +64,7 @@ void set_current(uint8_t motor, float amps)
 #if defined(CURRENT_I2C) && defined(CURRENT_MCP44XX_ADDR)
     uint8_t command[] = {
         uint8_t(wiperRegs[motor] << 4),
-        uint8_t(std::round(amps * CURRENT_FACTOR)),
+        uint8_t(std::min(255.0, std::max(0.0, std::round(amps * CURRENT_FACTOR)))),
     };
     CURRENT_I2C.MasterTransmit(CURRENT_MCP44XX_ADDR, command, sizeof(command), false);
     while (CURRENT_I2C.GetStatus().busy)

grbl/config.h

@@ -731,8 +731,8 @@
 #define DEFAULT_X_ACCELERATION (5000.0*60*60) // 5000*60*60 mm/min^2 = 5000 mm/sec^2
 #define DEFAULT_Y_ACCELERATION (5000.0*60*60) // 5000*60*60 mm/min^2 = 5000 mm/sec^2
 #define DEFAULT_Z_ACCELERATION (5000.0*60*60) // 5000*60*60 mm/min^2 = 5000 mm/sec^2
-#define DEFAULT_X_CURRENT 0.4 // amps
-#define DEFAULT_Y_CURRENT 1.5 // amps
+#define DEFAULT_X_CURRENT 0.0 // amps
+#define DEFAULT_Y_CURRENT 0.0 // amps
 #define DEFAULT_Z_CURRENT 0.0 // amps
 #define DEFAULT_A_CURRENT 0.0  // amps
 #define DEFAULT_X_MAX_TRAVEL 200.0 // mm

grbl/grbl.h

@@ -62,6 +62,7 @@
 #include "spindle_control.h"
 #include "stepper.h"
 #include "jog.h"
+#include "current_control.h"
 
 // ---------------------------------------------------------------------------------------
 // COMPILE-TIME ERROR CHECKING OF DEFINE VALUES:

grbl/main.c

@@ -20,7 +20,6 @@
 */
 
 #include "grbl.h"
-#include "current_control.h"
 
 void isr_init();
 

grbl/report.c

@@ -218,6 +218,7 @@ void report_grbl_settings() {
         case 1: report_util_float_setting(val+idx,settings.max_rate[idx],N_DECIMAL_SETTINGVALUE); break;
         case 2: report_util_float_setting(val+idx,settings.acceleration[idx]/(60*60),N_DECIMAL_SETTINGVALUE); break;
         case 3: report_util_float_setting(val+idx,-settings.max_travel[idx],N_DECIMAL_SETTINGVALUE); break;
+        case 4: report_util_float_setting(val+idx,settings.current[idx],N_DECIMAL_SETTINGVALUE); break;
       }
     }
     val += AXIS_SETTINGS_INCREMENT;

grbl/settings.c

@@ -117,6 +117,9 @@ void settings_restore(uint8_t restore_flag) {
     settings.max_travel[X_AXIS] = (-DEFAULT_X_MAX_TRAVEL);
     settings.max_travel[Y_AXIS] = (-DEFAULT_Y_MAX_TRAVEL);
     settings.max_travel[Z_AXIS] = (-DEFAULT_Z_MAX_TRAVEL);
+    settings.current[X_AXIS] = DEFAULT_X_CURRENT;
+    settings.current[Y_AXIS] = DEFAULT_Y_CURRENT;
+    settings.current[Z_AXIS] = DEFAULT_Z_CURRENT;
 
     write_global_settings(false);
   }
@@ -231,6 +234,10 @@ uint8_t settings_store_global_setting(uint8_t parameter, float value) {
             break;
           case 2: settings.acceleration[parameter] = value*60*60; break; // Convert to mm/min^2 for grbl internal use.
           case 3: settings.max_travel[parameter] = -value; break;  // Store as negative for grbl internal use.
+          case 4:
+            settings.current[parameter] = value;
+            set_current(parameter, settings.current[parameter]);
+            break;
         }
         break; // Exit while-loop after setting has been configured and proceed to the EEPROM write call.
       } else {

grbl/settings.h

@@ -70,7 +70,7 @@
 // #define SETTING_INDEX_G92    N_COORDINATE_SYSTEM+2  // Coordinate offset (G92.2,G92.3 not supported)
 
 // Define Grbl axis settings numbering scheme. Starts at START_VAL, every INCREMENT, over N_SETTINGS.
-#define AXIS_N_SETTINGS          4
+#define AXIS_N_SETTINGS          5
 #define AXIS_SETTINGS_START_VAL  100 // NOTE: Reserving settings values >= 100 for axis settings. Up to 255.
 #define AXIS_SETTINGS_INCREMENT  10  // Must be greater than the number of axis settings
 
@@ -81,6 +81,7 @@ typedef struct {
   float max_rate[N_AXIS];
   float acceleration[N_AXIS];
   float max_travel[N_AXIS];
+  float current[N_AXIS];
 
   // Remaining Grbl settings
   uint8_t pulse_microseconds;