connect LCD to Mini-Pro

Projects General Guidance
1

I'm trying to connect my LCD to the Mini-Pro using SCL and SCA
but I can't see the LCD.
if I take it to my Arduino Ethernet (with the same cables) it's work. - so the LCD and cables are O.K
how do I know if I need to add a pullup ?(when I work with the Ethernet I don't use any)
from what I have found online - if the LCD work on the Arduino Ethernet without any resistors it should work on the Mini-Pro without it.

when I run the I2C_scanner.ino
it get stuck - I have check the wires and there isn't short circuit , or something .
what could be the problem ?

Thanks,

2

You did not mix SCL and SCA?

And how do you mean, get stuck??

3

I didn't mix (I have look many times)
and as you can see on the last line - this is what I mean "stuck"

Found 0 device(s).
Found 0 device(s).
Done.
Found 0 device(s).
Done.
Found 0 device(s).

Done.
Found 0 devi

I made the code run in loop ,
and when I connect the LCD (SCL+SDA) it's stuck

4

And did you connect the power en GND to Vcc and GND of the pro Mini?

And it's not by any change a 3,3V Pro Mini?

5

it's 5V for sure
and just to be clear -
A4 -SCl
A5-SDA
Right?

because when I search examples on google I see the other way around

6

I have A4 = SDA and A5 = SCL, same as the Uno... So that is the wrong way around :wink:

7

now it's working

Thanks ,