#include <Arduino.h>
#include <Arduino.h>
#include <U8g2lib.h>
#include <SPI.h>
#include <Wire.h>

U8G2_SH1106_128X64_NONAME_1_HW_I2C u8g2(U8G2_R2);

int boostPressure;

unsigned long startMillis;
unsigned long currentMillis;
const unsigned long period = 50;

void readSensorData(void) 
{
  float absolutePressure = analogRead(A3);
  boostPressure = map(absolutePressure, 102, 921, 0, 3000) - 1000;
}


void setup(void) 
{
  u8g2.begin();
  startMillis = millis();
}


void loop(void) 
{
  // Only read from the sensors every 50 ms
  currentMillis = millis();
  if (currentMillis - startMillis >= period) 
  {
    readSensorData();
    startMillis = currentMillis;
  }

  u8g2.firstPage();
  do 
  {
    // Draw current pressure
    u8g2.setFont(u8g2_font_fub25_tf);
    char cstr[6];
    dtostrf((float)boostPressure / 1000, 1, 3, cstr);
    u8g2.drawStr(0, 50, cstr);
  } 
  while ( u8g2.nextPage() );
}