✨ Add M3426 A<addr> parameter (#24130)

Co-authored-by: Scott Lahteine <github@thinkyhead.com>

Marlin/src/feature/adc/adc_mcp3426.cpp

 #include "adc_mcp3426.h"
 
 // Read the ADC value from MCP342X on a specific channel
-int16_t MCP3426::ReadValue(uint8_t channel, uint8_t gain) {
+int16_t MCP3426::ReadValue(uint8_t channel, uint8_t gain, uint8_t address) {
   Error = false;
 
   #if PINS_EXIST(I2C_SCL, I2C_SDA) && DISABLED(SOFT_I2C_EEPROM)
 
   Wire.begin(); // No address joins the BUS as the master
 
-  Wire.beginTransmission(I2C_ADDRESS(MCP342X_ADC_I2C_ADDRESS));
+  Wire.beginTransmission(I2C_ADDRESS(address));
 
   // Continuous Conversion Mode, 16 bit, Channel 1, Gain x4
   // 26 = 0b00011000
   uint8_t buffer[len] = {};
 
   do {
-    Wire.requestFrom(I2C_ADDRESS(MCP342X_ADC_I2C_ADDRESS), len);
+    Wire.requestFrom(I2C_ADDRESS(address), len);
     if (Wire.available() != len) {
       Error = true;
       return 0;

Marlin/src/feature/adc/adc_mcp3426.h

 #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);
+    int16_t ReadValue(uint8_t channel, uint8_t gain, uint8_t address);
     bool Error;
 };
 

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

 
 #include "../../../feature/adc/adc_mcp3426.h"
 
+#define MCP3426_BASE_ADDR (0b1101 << 3)
+
 /**
  * M3426: Read 16 bit (signed) value from I2C MCP3426 ADC device
  *
  *  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;
+  uint8_t channel = parser.byteval('C', 1), // Channel 1 or 2
+             gain = parser.byteval('G', 1), // Gain 1, 2, 4, or 8
+          address = parser.byteval('A', 3); // Address 0-7 (or 104-111)
+  const bool inverted = parser.boolval('I');
+
+  if (address <= 7) address += MCP3426_BASE_ADDR;
 
-  if (channel <= 2 && (gain == 1 || gain == 2 || gain == 4 || gain == 8)) {
-    int16_t result = mcp3426.ReadValue(channel, gain);
+  if (WITHIN(channel, 1, 2) && (gain == 1 || gain == 2 || gain == 4 || gain == 8) && WITHIN(address, MCP3426_BASE_ADDR, MCP3426_BASE_ADDR + 7)) {
+    int16_t result = mcp3426.ReadValue(channel, gain, address);
 
     if (mcp3426.Error == false) {
       if (inverted) {