I'm approaching the end of my wisdom and I hope you can help me! I have a 16/2 display, controlled via I2C. With the libraries of fm it works perfectly on my Arduino Duemilanove. If I upload the exact same sketch to my Nano, wire everything exact the same way (believe me, 10 times doublechecked), the display is lighened, but no chance that there would appear any letters.
I'm using 10k pull-up resistors, the display is some no name product with a I2C adaptor from YwRobot (LCM1602).
As I said, exactly the same way wired, exact the same sketch.
Stop, there's one difference: On the Duemilanove, I power the display via the 5V and GND pin, on the Nano i take 2 digital pins for this, so in the sketch for the Nano there's this bit of code which gives power to those two pins.
Thanks for your response! Actually I don't have other pull-ups around, but I can try, probably I'll find some in a shop. Could this make the difference, since it does work with the Duemilanove? (I actually tried it without on both Arduinos, same result)
Yes, the power is supplied directly from the Arduino. There's nothing else connected.
Do you know how much power the display consumes? Can you measure it?
The pull-ups can make the difference although it's unusual that such a setup works with one Arduino but not the other. That's why I'm asking for the power consumption. A description of the consequences of different pull-ups can be found here:
I measured it, it says about 16mA. Anyways, I tried it with the 5V and GND pin on the Nano, the displeay seems a bit brighter to me, but nothing changed so far.
I'm looking for lower values in the internet, but actually I cant find anything around 3.3k
I'm sure I'm using the right pins I power the Arduino via USB, but also tried 9V via the VIN pin, again, the display seems a bit brighter but no change. Unfortunately I don't have an oscilloscope.
I have a problem with your bit of code, I tried to insert it and get a bunch of errors, "expected unqualified-id before 'volatile'". I tried google it but didn't find anything out. Since I'm not using a Wire.begin(), I'm not sure where to put it.
It's probably time to show us your whole code, because if you don't use the Wire library it may be possible that you don't use the hardware I2C at all.
Post the code with the code tags (the hash # sign in the editor). Also include links in the post to all the libraries you use which are not part of the main IDE distribution.
Yes, I'll do that later, it's not possible at the moment.
Well, I AM using the WIre library, but I'm not calling any function with it. The LiquidCrystal_I2C (actually all such libraries) manage this by themselves, but the Wire library needs to be attached to the sketch.
I think i have tested every freaking code and library out there. Im using the FM 1.2.1 library for now. SDA is connected to A4 and SCL to A5. Im all ears people...
Edit: Forgot, the display lights up and displays only blobs on row 0 and row 2.
I bought the same adapter from emall-foryou but the hello world example from the LiquidCrystal_I2C library only flashes my display once during setup.
No characters are displayed.
1602 display, Arduino Nano v3.0 using A4/A5 and 0x20 as the I2C address.