// Basic demo for configuring the MCP4728 4-Channel 12-bit I2C DAC
#include <Adafruit_MCP4728.h>
#include <Wire.h>

Adafruit_MCP4728 mcp;

float xlog = 0.5;
float r = 3.783423;

void setup(void) {
  Serial.begin(115200);
  while (!Serial)
    delay(10); // will pause Zero, Leonardo, etc until serial console opens

  Serial.println("Adafruit MCP4728 test!");

  // Try to initialize!
  if (!mcp.begin(0x64)) {
    Serial.println("Failed to find MCP4728 chip");
    while (1) {
      delay(10);
    }
  }

  mcp.setChannelValue(MCP4728_CHANNEL_A, 4095);
  mcp.setChannelValue(MCP4728_CHANNEL_B, 2048);
  mcp.setChannelValue(MCP4728_CHANNEL_C, 1024);
  mcp.setChannelValue(MCP4728_CHANNEL_D, 0);


}


void loop() {
  int pot = analogRead(A0);
  r = (float)pot / 1024.0 + 3.0;
  xlog = r * xlog * (1 - xlog);
  int cv = round(xlog * 4095.0);  
  mcp.setChannelValue(MCP4728_CHANNEL_A, cv);
}