#include <Wire.h>
#include <LiquidCrystal_I2C.h>

/* ===== PIN CONFIG ===== */
#define DIP1 D3
#define DIP2 D4
#define DIP3 D5
#define DIP4 D6
#define DIP5 D7

#define ANALOG_IN A0
#define PULSE_OUT D9

#define I2C_SDA D2
#define I2C_SCL D8

LiquidCrystal_I2C lcd(0x27, 20, 4);

/* ===== MODE ===== */
int getMode() {
  if (digitalRead(DIP1)) return 1;
  if (digitalRead(DIP2)) return 2;
  if (digitalRead(DIP3)) return 3;
  if (digitalRead(DIP4)) return 4;
  if (digitalRead(DIP5)) return 5;
  return 0;
}

/* ===== ADC ===== */
float adcToVoltage(int adc) {
  return (adc * 3.3f) / 4095.0f;
}

/* ===== CONVERT ===== */
float convertToHz(float v, int mode) {
  switch (mode) {
    case 1: return constrain(v / 10.0 * 1000.0, 0, 1000);                 // 0-10V
    case 2: return constrain((v - 1.0) / 4.0 * 1000.0, 0, 1000);          // 4-20mA
    case 3: return constrain(v / 5.0 * 1000.0, 0, 1000);                 // 0-20mA
    case 4: return constrain((v - 1.65) / 3.3 * 1000.0 + 500, 0, 1000);   // +-10V
    case 5: return constrain((v - 1.65) / 3.3 * 1000.0 + 500, 0, 1000);   // +-20mA
  }
  return 0;
}

/* ===== PULSE ===== */
void setPulse(float hz) {
  if (hz < 1) {
    analogWrite(PULSE_OUT, 0);
    return;
  }
  analogWriteFrequency((uint32_t)hz);
  analogWrite(PULSE_OUT, 128); // 50%
}

/* ===== MODE NAME ===== */
const char* modeName(int mode) {
  switch (mode) {
    case 1: return "MODE 1 : 0-10V";
    case 2: return "MODE 2 : 4-20mA";
    case 3: return "MODE 3 : 0-20mA";
    case 4: return "MODE 4 : +-10V";
    case 5: return "MODE 5 : +-20mA";
  }
  return "NO MODE";
}

/* ===== SETUP ===== */
void setup() {
  pinMode(DIP1, INPUT);
  pinMode(DIP2, INPUT);
  pinMode(DIP3, INPUT);
  pinMode(DIP4, INPUT);
  pinMode(DIP5, INPUT);

  pinMode(PULSE_OUT, OUTPUT);

  Wire.setSDA(I2C_SDA);
  Wire.setSCL(I2C_SCL);
  Wire.begin();

  lcd.init();
  lcd.backlight();
}

/* ===== LOOP ===== */
void loop() {
  int mode = getMode();
  int adc = analogRead(ANALOG_IN);
  float v = adcToVoltage(adc);
  float hz = convertToHz(v, mode);

  setPulse(hz);

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(modeName(mode));

  lcd.setCursor(0, 1);
  lcd.print("ADC: ");
  lcd.print(adc);

  lcd.setCursor(0, 2);
  lcd.print("FREQ: ");
  lcd.print(hz, 1);
  lcd.print(" Hz");

  lcd.setCursor(0, 3);
  if (hz > 0) {
    lcd.print("PERIOD: ");
    lcd.print(1000.0 / hz, 2);
    lcd.print(" ms");
  } else {
    lcd.print("PERIOD: ---");
  }

  delay(300);
}