Thys may give you a direction


//Programa: Medidor de corrente com sensor ACS712
//Autor: Arduino e Cia

#include <Wire.h>
#include <U8glib.h>

//Definicoes do display Oled
U8GLIB_SSD1306_128X64 u8g(U8G_I2C_OPT_NONE);

//int valor = 0;
String str;
int tamanho;

const int analogIn = A0;
int ...

Try change Arduino IDE tool flash frequency to 40 Mhz

I noted that have several variants for pins_arduino.h

What is the correct way of code, to set Arduino IDE to use a specific variant?