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