// ============================================
// ESP32 + ADS1115 + MCP41010 Virtual Project
// ADS1115: 16-bit ADC via I2C (SDA=D21, SCL=D22)
// MCP41010: Digital Potentiometer via SPI
// ============================================

#include <Wire.h>
#include <SPI.h>

#define ADS1115_ADDR   0x48
#define ADS_REG_CONV   0x00
#define ADS_REG_CFG    0x01

// MCP41010 SPI Pins
#define MCP_CS    5
#define MCP_MOSI  23
#define MCP_SCK   18

byte mcp_wiper = 0;

void mcp41010_set(byte value) {
  SPI.beginTransaction(SPISettings(1000000, MSBFIRST, SPI_MODE0));
  digitalWrite(MCP_CS, LOW);
  SPI.transfer(0x11);
  SPI.transfer(value);
  digitalWrite(MCP_CS, HIGH);
  SPI.endTransaction();
}

int16_t ads1115_readSingleEnded(uint8_t channel) {
  uint16_t mux;
  switch (channel) {
    case 0: mux = 0x4000; break;
    case 1: mux = 0x5000; break;
    case 2: mux = 0x6000; break;
    case 3: mux = 0x7000; break;
    default: mux = 0x4000;
  }
  // Config: OS=1, MUX, PGA=+/-4.096V, MODE=single, DR=128SPS
  uint16_t config = 0x8000 | mux | 0x0200 | 0x0100 | 0x0080;
  Wire.beginTransmission(ADS1115_ADDR);
  Wire.write(ADS_REG_CFG);
  Wire.write((config >> 8) & 0xFF);
  Wire.write(config & 0xFF);
  Wire.endTransmission();

  delay(9); // wait for conversion

  Wire.beginTransmission(ADS1115_ADDR);
  Wire.write(ADS_REG_CONV);
  Wire.endTransmission();

  Wire.requestFrom((uint8_t)ADS1115_ADDR, (uint8_t)2);
  int16_t raw = 0;
  if (Wire.available() >= 2) {
    raw = (Wire.read() << 8) | Wire.read();
  }
  return raw;
}

void setup() {
  Serial.begin(115200);
  delay(500);
  Serial.println();
  Serial.println("==========================================");
  Serial.println(" ESP32 + ADS1115 + MCP41010 Virtual Proj");
  Serial.println("==========================================");

  Wire.begin(21, 22);

  // SPI for MCP41010
  SPI.begin(MCP_SCK, -1, MCP_MOSI, MCP_CS);
  pinMode(MCP_CS, OUTPUT);
  digitalWrite(MCP_CS, HIGH);

  Serial.println("[OK] ADS1115 + MCP41010 initialized!");
  Serial.println();
  Serial.println("DAC% | MCP Val | ADC Raw | Voltage");
  Serial.println("-----|---------|---------|--------");
}

void loop() {
  // Sweep MCP41010 wiper 0-255
  for (int step = 0; step <= 255; step += 32) {
    mcp_wiper = step;
    mcp41010_set(mcp_wiper);

    delay(50);

    int16_t raw = ads1115_readSingleEnded(0);
    float voltage = raw * 4.096f / 32767.0f;

    Serial.print(step * 100 / 255);
    Serial.print("% | ");
    Serial.print(step);
    Serial.print("  | ");
    Serial.print(raw);
    Serial.print("  | ");
    Serial.print(voltage, 4);
    Serial.println(" V");
  }
  Serial.println("--- Sweep done ---");
  delay(2000);
}