#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
/*user functions*/
char readDHT(int pin,float *h,float *t);
int readByte(int pin);
int checkSum(int pin);
void initDisplay(void);

Adafruit_SSD1306 display = Adafruit_SSD1306(128, 64, &Wire);

void setup() {
  Serial.begin(9600);
  initDisplay();
  float t,h;
  readDHT(2,&h,&t);
  // put your setup code here, to run once:
}

void loop() {
  float t,h;
  readDHT(2,&h,&t);
  display.setCursor(30, 10);
  display.print(h);
  display.setCursor(30, 35);
  display.print(t);
  display.display();
  delay(1000);
  display.clearDisplay();
  display.display();

  // put your main code here, to run repeatedly:
}
/*
@fn char readDHT(int pin)
@brief función que obiene los valores de temperatura y humedad
@param[in] pin: valor de pin para envio y recepcion de datos
@param[out] t: temperatura 
@param[out] h: humedad
@return 0: ok | 1: fallo
*/
char readDHT(int pin,float *h,float *t){
  pinMode(pin,OUTPUT);
  digitalWrite(pin,LOW);
  delay(2);
  digitalWrite(pin,HIGH);
  delayMicroseconds(30);
  pinMode(pin,INPUT);

  while(digitalRead(pin));
  while(!digitalRead(pin));
  while(digitalRead(pin));


  short data[3] = {0};
  data[0] = readByte(pin);
  data[1] = readByte(pin);
  data[2] = checkSum(pin);
  
  unsigned char A = ((data[0] & 0xFF00)>>8);
  unsigned char B = (data[0] & 0xFF);
  unsigned char C = ((data[1] & 0xFF00)>>8);
  unsigned char D = (data[1] & 0xFF);

  unsigned char checkSum = (A+B+C+D);
  if(checkSum == data[2]){
    *t = data[1];
    *t /= 10;
    *h = data[0];
    *h /= 10;
  }
  else 
    return 1;
}
/*
@fn 
@brief 
@param[in] 
@param[out]  
@param[out] 
@return 
*/
int readByte(int pin){
  int data = 0;
  for(int i= 0; i < 16; i++){
    while(!digitalRead(pin));//hasta que se vuelva 1
    delayMicroseconds(30);
    if(digitalRead(pin)){
      //data = ((data<<1) | 1);
      Serial.print("1");
    }else{
      //data = (data<<1);
      Serial.print("0");
    }
    while(digitalRead(pin));//hasta que se vuelva 0
  }
  return data;
}
/*
@fn 
@brief 
@param[in] 
@param[out]  
@param[out] 
@return 
*/
int checkSum(int pin){
  int data = 0;
  for(int i= 0; i < 8; i++){
    while(!digitalRead(pin));//hasta que se vuelva 1
    delayMicroseconds(30);
    if(digitalRead(pin)){
      data = ((data<<1) | 1);
    }else{
      data = (data<<1);
    }
    while(digitalRead(pin));//hasta que se vuelva 0
  }
  return data;
}

void initDisplay(void){
  display.begin(SSD1306_SWITCHCAPVCC,0x3c );
  display.clearDisplay();
  display.setTextColor(SSD1306_WHITE);
  display.clearDisplay();
  display.setTextSize(2); // x2 pixel
  display.setCursor(30, 20);//3 renglones, depende el tamaño 
  display.print("Hello!");
  display.display();
  delay(2000);
  display.clearDisplay();
  display.display();
}