Arduino 328 || Mega 2560 + I2C =?

Community General Discussions
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1

 

As you can see in following 1st photo; connecting LCD to arduino 328 and 2560 by using I2C. 2560 works fine but 328 doesn't work. Both board has exact same code. I have tried to swap the LCD, or not using the I/O shield or switch A4,A5 pin. Either way the LCD doesn't work. Thanks in advance if anyone has any ideas~~

IMAG0880.jpg

Mega 2560 on top left and 328 on lower right.

 

IMAG0881.jpg

The connection in between UNO and I2C/LCD. Only showing cubes...

 

IMAG0882.jpg

MEGA with LCD work fine!

 

2

Pull ups?

Are there pull up resistors on one board but not the other? If using internal pull-ups, are they turned on?

3

I don’t really see any pull

I don’t really see any pull up resistors but some jumpers for RS485 only.