Simple class to use Analog Device's AD5243 - 256-Position Dual Channel I2C Compatible Digital Potentiometer

AD5243.h

/* MIT License
Copyright (c) 2017 Justin Decker
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
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The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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SOFTWARE.

Datasheet: https://www.analog.com/en/products/ad5243.html
Resistance set is measured between B1 and W1 for channel 0, and B2 and W2 for channel 1

Simple example
---
#include "AD5243.h"
AD5243 variable_pot(100000);
void setup() {
  Wire.begin();
  variable_pot.begin();
  variable_pot.setResistance(0, 12700);  // channel (0 or 1), and resistance in ohms
  variable_pot.setResistance(1, 47000);
}
void loop() {}
---
*/
#pragma once
#include "Arduino.h"
#include <Wire.h>

#define AD5243_I2C_ADDRESS 0x2f

class AD5243
{
  public:
    uint32_t channel1Resistance;
    uint32_t channel2Resistance;
    AD5243(long total_resistance)
    {
      _total_resistance = total_resistance;
    }

    bool begin(TwoWire &wirePort=Wire, uint8_t address=AD5243_I2C_ADDRESS)
    {
      _address = address;
      _i2cPort = &wirePort;

      return connected();
    }

    bool connected()
    {
      _i2cPort->beginTransmission(_address);
      uint8_t retval = _i2cPort->endTransmission();

      if (retval)
      {
        return false;
      }
      else
      {
        return true;
      }
    }

    bool setResistance(uint8_t channel, long resistance)
    {
      uint8_t b[5];
      byte step = (255.0 * ((float)resistance / (float)_total_resistance));
      byte _channel = 0;

      if (channel == 1)
      {
        _channel = 128;
        channel2Resistance = resistance;
      }
      else
      {
        channel1Resistance = resistance;
      }

      b[0] = _channel;
      b[1] = step;
      _i2cPort->beginTransmission(_address);
      _i2cPort->write(b, 2);
      uint8_t retval = _i2cPort->endTransmission();

      if (retval)
      {
        return false;
      }
      else
      {
        return true;
      }
    }
  private:
    uint8_t _address;
    TwoWire *_i2cPort;
    long _resistance;
    long _total_resistance;
};