✨ M3426 to read i2c MCP3426 ADC (#23184)

Marlin/src/gcode/feature/adc/M3426.cpp

@@ -0,0 +1,63 @@
+/**
+ * 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(HAS_MCP3426_ADC)
+
+#include "../../gcode.h"
+
+#include "../../../feature/adc/adc_mcp3426.h"
+
+/**
+ * M3426: Read 16 bit (signed) value from I2C MCP3426 ADC device
+ *
+ *  M3426 C<byte-1 value in base 10> channel 1 or 2
+ *  M3426 G<byte-1 value in base 10> gain 1, 2, 4 or 8
+ *  M3426 I<byte-2 value in base 10> 0 or 1, invert reply
+ */
+void GcodeSuite::M3426() {
+  uint8_t channel = parser.byteval('C', 1),       // Select the channel 1 or 2
+             gain = parser.byteval('G', 1);
+  const bool inverted = parser.byteval('I') == 1;
+
+  if (channel <= 2 && (gain == 1 || gain == 2 || gain == 4 || gain == 8)) {
+    int16_t result = mcp3426.ReadValue(channel, gain);
+
+    if (mcp3426.Error == false) {
+      if (inverted) {
+        // Should we invert the reading (32767 - ADC value) ?
+        // Caters to end devices that expect values to increase when in reality they decrease.
+        // e.g., A pressure sensor in a vacuum when the end device expects a positive pressure.
+        result = INT16_MAX - result;
+      }
+      //SERIAL_ECHOPGM(STR_OK);
+      SERIAL_ECHOLNPGM("V:", result, " C:", channel, " G:", gain, " I:", inverted ? 1 : 0);
+    }
+    else
+      SERIAL_ERROR_MSG("MCP342X i2c error");
+  }
+  else
+    SERIAL_ERROR_MSG("MCP342X Bad request");
+}
+
+#endif // HAS_MCP3426_ADC