Add Laser Based I2C Ammeter Feature (#21835)

Marlin/src/feature/ammeter.cpp

@@ -0,0 +1,49 @@
+  /**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program 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.
+ *
+ * This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "../inc/MarlinConfig.h"
+
+#if ENABLED(I2C_AMMETER)
+  #include "ammeter.h"
+
+  INA226 ina;
+
+  Ammeter ammeter;
+
+  float Ammeter::scale;
+  float Ammeter::current;
+
+  void Ammeter::init() {
+    ina.begin();
+    ina.configure(INA226_AVERAGES_16, INA226_BUS_CONV_TIME_1100US, INA226_SHUNT_CONV_TIME_1100US, INA226_MODE_SHUNT_BUS_CONT);
+    ina.calibrate(I2C_AMMETER_SHUNT_RESISTOR,I2C_AMMETER_IMAX);
+  }
+
+  float Ammeter::read() {
+      scale = 1;
+      current = ina.readShuntCurrent();
+      if (current <= .0001) current = 0;  // Cleanup lsb bit amplification errors
+      if (current < .1) scale = 1000; 
+      return current * scale;
+  }
+
+#endif //I2C_AMMETER

Marlin/src/feature/ammeter.h

@@ -0,0 +1,44 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program 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.
+ *
+ * This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#pragma once
+
+#include "../inc/MarlinConfigPre.h"
+
+#include <Wire.h>
+#include <INA226.h>
+
+#ifndef I2C_AMMETER_IMAX    
+  #define I2C_AMMETER_IMAX      .500 // Calibration range 500 Milli Amps
+#endif
+
+class Ammeter {
+private:
+    static float scale;
+
+public:
+    static float current;
+    static void init();
+    static float read();
+ 
+};
+
+extern Ammeter ammeter;

Marlin/src/feature/spindle_laser.cpp

@@ -34,6 +34,10 @@
   #include "../module/servo.h"
 #endif
 
+#if ENABLED(I2C_AMMETER)
+  #include "../feature/ammeter.h"
+#endif
+
 SpindleLaser cutter;
 uint8_t SpindleLaser::power;
 #if ENABLED(LASER_FEATURE)
@@ -74,6 +78,10 @@ void SpindleLaser::init() {
   #if ENABLED(AIR_ASSIST)
     OUT_WRITE(AIR_ASSIST_PIN, !AIR_ASSIST_ACTIVE);                    // Init Air Assist OFF
   #endif
+  #if ENABLED(I2C_AMMETER)
+    ammeter.init();                    // Init I2C Ammeter
+  #endif
+  
 }
 
 #if ENABLED(SPINDLE_LASER_PWM)