✨ M3426 to read i2c MCP3426 ADC (#23184)

Marlin/src/feature/adc/adc_mcp3426.cpp

@@ -0,0 +1,104 @@
+/**
+ * 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/>.
+ *
+ */
+
+/**
+ * adc_mcp3426.cpp -  library for MicroChip MCP3426 I2C A/D converter
+ *
+ * For implementation details, please take a look at the datasheet:
+ * https://www.microchip.com/en-us/product/MCP3426
+ */
+
+#include "../../inc/MarlinConfig.h"
+
+#if ENABLED(HAS_MCP3426_ADC)
+
+#include "adc_mcp3426.h"
+
+// Read the ADC value from MCP342X on a specific channel
+int16_t MCP3426::ReadValue(uint8_t channel, uint8_t gain) {
+  Error = false;
+
+  #if PINS_EXIST(I2C_SCL, I2C_SDA) && DISABLED(SOFT_I2C_EEPROM)
+    Wire.setSDA(pin_t(I2C_SDA_PIN));
+    Wire.setSCL(pin_t(I2C_SCL_PIN));
+  #endif
+
+  Wire.begin(); // No address joins the BUS as the master
+
+  Wire.beginTransmission(I2C_ADDRESS(MCP342X_ADC_I2C_ADDRESS));
+
+  // Continuous Conversion Mode, 16 bit, Channel 1, Gain x4
+  // 26 = 0b00011000
+  //        RXXCSSGG
+  //  R = Ready Bit
+  // XX = Channel (00=1, 01=2, 10=3 (MCP3428), 11=4 (MCP3428))
+  //  C = Conversion Mode Bit (1=  Continuous Conversion Mode (Default))
+  // SS = Sample rate, 10=15 samples per second @ 16 bits
+  // GG = Gain 00 =x1
+  uint8_t controlRegister = 0b00011000;
+
+  if (channel == 2) controlRegister |= 0b00100000; // Select channel 2
+
+  if (gain == 2)
+    controlRegister |= 0b00000001;
+  else if (gain == 4)
+    controlRegister |= 0b00000010;
+  else if (gain == 8)
+    controlRegister |= 0b00000011;
+
+  Wire.write(controlRegister);
+  if (Wire.endTransmission() != 0) {
+    Error = true;
+    return 0;
+  }
+
+  const uint8_t len = 3;
+  uint8_t buffer[len] = {};
+
+  do {
+    Wire.requestFrom(I2C_ADDRESS(MCP342X_ADC_I2C_ADDRESS), len);
+    if (Wire.available() != len) {
+      Error = true;
+      return 0;
+    }
+
+    for (uint8_t i = 0; i < len; ++i)
+      buffer[i] = Wire.read();
+
+    // Is conversion ready, if not loop around again
+  } while ((buffer[2] & 0x80) != 0);
+
+  union TwoBytesToInt16 {
+    uint8_t bytes[2];
+    int16_t integervalue;
+  };
+  TwoBytesToInt16 ConversionUnion;
+
+  ConversionUnion.bytes[1] = buffer[0];
+  ConversionUnion.bytes[0] = buffer[1];
+
+  return ConversionUnion.integervalue;
+}
+
+MCP3426 mcp3426;
+
+#endif // HAS_MCP3426_ADC

Marlin/src/feature/adc/adc_mcp3426.h

@@ -0,0 +1,41 @@
+/**
+ * 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
+
+/**
+ * Arduino library for MicroChip MCP3426 I2C A/D converter.
+ * https://www.microchip.com/en-us/product/MCP3426
+ */
+
+#include <stdint.h>
+#include <Wire.h>
+
+// Address of MCP342X chip
+#define MCP342X_ADC_I2C_ADDRESS 104
+
+class MCP3426 {
+  public:
+    int16_t ReadValue(uint8_t channel, uint8_t gain);
+    bool Error;
+};
+
+extern MCP3426 mcp3426;

Marlin/src/feature/twibus.cpp

@@ -34,13 +34,18 @@ TWIBus i2c;
 
 TWIBus::TWIBus() {
   #if I2C_SLAVE_ADDRESS == 0
-    Wire.begin(                    // No address joins the BUS as the master
-      #if PINS_EXIST(I2C_SCL, I2C_SDA) && DISABLED(SOFT_I2C_EEPROM)
-        pin_t(I2C_SDA_PIN), pin_t(I2C_SCL_PIN)
-      #endif
-    );
+
+    #if PINS_EXIST(I2C_SCL, I2C_SDA) && DISABLED(SOFT_I2C_EEPROM)
+      Wire.setSDA(pin_t(I2C_SDA_PIN));
+      Wire.setSCL(pin_t(I2C_SCL_PIN));
+    #endif
+
+    Wire.begin();                    // No address joins the BUS as the master
+
   #else
+
     Wire.begin(I2C_SLAVE_ADDRESS); // Join the bus as a slave
+
   #endif
   reset();
 }