✨ M3426 to read i2c MCP3426 ADC (MarlinFirmware#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();
 }

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

Marlin/src/gcode/gcode.cpp

@@ -1054,6 +1054,10 @@ void GcodeSuite::process_parsed_command(const bool no_ok/*=false*/) {
         case 7219: M7219(); break;                                // M7219: Set LEDs, columns, and rows
       #endif
 
+      #if ENABLED(HAS_MCP3426_ADC)
+        case 3426: M3426(); break;                                // M3426: Read MCP3426 ADC (over i2c)
+      #endif
+
       default: parser.unknown_command_warning(); break;
     }
     break;

Marlin/src/gcode/gcode.h

@@ -297,6 +297,7 @@
  * M917 - L6470 tuning: Find minimum current thresholds. (Requires at least one _DRIVER_TYPE L6470)
  * M918 - L6470 tuning: Increase speed until max or error. (Requires at least one _DRIVER_TYPE L6470)
  * M951 - Set Magnetic Parking Extruder parameters. (Requires MAGNETIC_PARKING_EXTRUDER)
+ * M3426 - Read MCP3426 ADC over I2C. (Requires HAS_MCP3426_ADC)
  * M7219 - Control Max7219 Matrix LEDs. (Requires MAX7219_GCODE)
  *
  *** SCARA ***
@@ -1204,6 +1205,10 @@ class GcodeSuite {
     static void M1004();
   #endif
 
+  #if ENABLED(HAS_MCP3426_ADC)
+    static void M3426();
+  #endif
+
   #if ENABLED(MAX7219_GCODE)
     static void M7219();
   #endif

Marlin/src/pins/stm32f4/pins_INDEX_REV03.h

@@ -42,6 +42,9 @@
 #define SRAM_EEPROM_EMULATION
 #define MARLIN_EEPROM_SIZE                0x2000  // 8KB
 
+// I2C MCP3426 (16-Bit, 240SPS, dual-channel ADC)
+#define HAS_MCP3426_ADC
+
 //
 // Servos
 //
@@ -116,6 +119,8 @@
 #define FAN2_PIN                            PE4
 #define FAN3_PIN                            PE5
 
+#define FAN_SOFT_PWM
+
 // Neopixel Rings
 #define NEOPIXEL_PIN                        PC7
 #define NEOPIXEL2_PIN                       PC8

ini/features.ini

@@ -94,6 +94,7 @@ NEXTION_TFT                            = src_filter=+<src/lcd/extui/nextion>
 USE_UHS2_USB                           = src_filter=+<src/sd/usb_flashdrive/lib-uhs2>
 USE_UHS3_USB                           = src_filter=+<src/sd/usb_flashdrive/lib-uhs3>
 USB_FLASH_DRIVE_SUPPORT                = src_filter=+<src/sd/usb_flashdrive/Sd2Card_FlashDrive.cpp>
+HAS_MCP3426_ADC                        = src_filter=+<src/feature/adc> +<src/gcode/feature/adc>
 AUTO_BED_LEVELING_BILINEAR             = src_filter=+<src/feature/bedlevel/abl>
 AUTO_BED_LEVELING_(3POINT|(BI)?LINEAR) = src_filter=+<src/gcode/bedlevel/abl>
 MESH_BED_LEVELING                      = src_filter=+<src/feature/bedlevel/mbl> +<src/gcode/bedlevel/mbl>

platformio.ini

@@ -92,6 +92,7 @@ default_src_filter = +<src/*> -<src/config> -<src/HAL> +<src/HAL/shared>
   -<src/HAL/shared/cpu_exception>
   -<src/HAL/shared/eeprom_if_i2c.cpp>
   -<src/HAL/shared/eeprom_if_spi.cpp>
+  -<src/feature/adc> -<src/gcode/feature/adc>
   -<src/feature/babystep.cpp>
   -<src/feature/backlash.cpp>
   -<src/feature/baricuda.cpp> -<src/gcode/feature/baricuda>