#include <Adafruit_SSD1306.h>                         //OLED
#include <Wire.h>                                     //SPI

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
#define OLED_RESET     -1 // Reset pin # (or -1 if sharing Arduino reset pin)
#define SCREEN_ADDRESS 0x3C ///< See datasheet for Address; 0x3D for 128x64, 0x3C for 128x32
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

#define BTN_PIN 4                       //define pino do botão
#define LED_PIN 14                      //define pino do led
#define POT_PIN 34

int i = 0;                              //variavel de controle uso geral
boolean state_LED;                      //variavel de status do led
int potenc;
float potenc_v;
int serial_read = 0;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");


  pinMode(BTN_PIN, INPUT_PULLUP);
  pinMode(LED_PIN, OUTPUT);
  pinMode(POT_PIN, INPUT);

  if (!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {

    for (;;); // Don't proceed, loop forever
  }

  display.clearDisplay();
  display.setTextSize(2);           
  display.setTextColor(SSD1306_WHITE);      
  
}

void loop() {

      if (!digitalRead(BTN_PIN)){
      potenc = (analogRead(POT_PIN));
      potenc_v = (potenc*(3.3/4095));
      display.setCursor(35,10); 
      display.print("BLOCK");
      display.setCursor(30,30);
      display.print(potenc_v); 
      display.print(" V");
      display.display();
      Serial.print(potenc_v);
      Serial.println (" V");
      while (!digitalRead(BTN_PIN)){
      state_LED = digitalRead(LED_PIN);
      digitalWrite(LED_PIN,!state_LED);
      delay(250);
      }
      }
    state_LED = digitalRead(LED_PIN);
    digitalWrite(LED_PIN,!state_LED);
    display.display();
    display.clearDisplay();
    delay(1000);
    if (Serial.available() > 0) {
    serial_read = Serial.read();
    Serial.print (serial_read);
    }
}