Hey Guys,
I don’t understand life anymore since I tried everything to make this work:
The Atmega328P running on a breadboard as an 8mhz internal configuration and it is bootloaded/programmed by an Arduino Uno as ISP. Programming for Blink Sketch works fine.
Now the situation is as follows:
-I try to connect the AtMega to an I2C LCD
5V – Vcc
GND – GND
Pin 20 (A5 ) – SCL
Pin 19 (A4) – SDA
-Using the ‘Hello World Example’, text should appear when uploaded and connected.
-Using an I2C scanner sketch, an LED on D13 should light up when it detects an I2C device.
All of the above works using an Arduino Uno but does not when using the Breadboard AtMega
Thanks in advance
Florian
PS: Code
“Hello World example”
Arduino Uno: LCD shows the the text that is sent to it
AtMega Standalone: LCD does nothing
//YWROBOT
//Compatible with the Arduino IDE 1.0
//Library version:1.1
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,20,4); // set the LCD address to 0x27 for a 16 chars and 2 line display
void setup()
{
lcd.init(); // initialize the lcd
lcd.init();
// Print a message to the LCD.
lcd.backlight();
lcd.setCursor(3,0);
lcd.print("Hello, world!");
lcd.setCursor(2,1);
lcd.print("Ywrobot Arduino!");
lcd.setCursor(0,2);
lcd.print("Arduino LCM IIC 2004");
lcd.setCursor(2,3);
lcd.print("Power By Ec-yuan!");
}
void loop()
{
}
I2C Scanner from Arduino Website:
Arduino Uno: writes to Serial Monitor that a device is found at adress 0x27, LED lights up when LCD is connected, goes out when disconnected.
AtMega Standalone: (Cannot check serial monitor); LED does not light up when LCD is connected.
// --------------------------------------
// i2c_scanner
//
// Version 1
// This program (or code that looks like it)
// can be found in many places.
// For example on the Arduino.cc forum.
// The original author is not know.
// Version 2, Juni 2012, Using Arduino 1.0.1
// Adapted to be as simple as possible by Arduino.cc user Krodal
// Version 3, Feb 26 2013
// V3 by louarnold
// Version 4, March 3, 2013, Using Arduino 1.0.3
// by Arduino.cc user Krodal.
// Changes by louarnold removed.
// Scanning addresses changed from 0...127 to 1...119,
// according to the i2c scanner by Nick Gammon
// http://www.gammon.com.au/forum/?id=10896
// Version 5, March 28, 2013
// As version 4, but address scans now to 127.
// A sensor seems to use address 120.
// Version 6, November 27, 2015.
// Added waiting for the Leonardo serial communication.
//
//
// This sketch tests the standard 7-bit addresses
// Devices with higher bit address might not be seen properly.
//
#include <Wire.h>
void setup()
{
Wire.begin();
Serial.begin(9600);
while (!Serial); // Leonardo: wait for serial monitor
Serial.println("\nI2C Scanner");
pinMode(13,OUTPUT);
digitalWrite(13,LOW);
}
void loop()
{
byte error, address;
int nDevices;
Serial.println("Scanning...");
nDevices = 0;
for(address = 1; address < 127; address++ )
{
// The i2c_scanner uses the return value of
// the Write.endTransmisstion to see if
// a device did acknowledge to the address.
Wire.beginTransmission(address);
error = Wire.endTransmission();
if (error == 0)
{
Serial.print("I2C device found at address 0x");
digitalWrite(13,HIGH);
if (address<16)
Serial.print("0");
Serial.print(address,HEX);
Serial.println(" !");
nDevices++;
}
else if (error==4)
{
Serial.print("Unknown error at address 0x");
if (address<16)
Serial.print("0");
Serial.println(address,HEX);
}
}
if (nDevices == 0){
Serial.println("No I2C devices found\n");
digitalWrite(13,LOW);
}
else
Serial.println("done\n");
delay(5000); // wait 5 seconds for next scan
}
But yeah, motors are very good at generating that 
Stupid mechanics...