VMA450 display 20x4 doesn't work

I have got a 20x4 VMA450 display but whatever I try, the display won’t work. Only thing I see is the second line and the 4th line is showing blocks. Do I need some special connection?
I already added the driver to my project but nothing will work…


@A.r.c ,

Maybe lowering the contrast might help.

Normally the connections are, see manual §6

then use the correct library: Can be downloaded from here: https://www.velleman.eu/downloads/29/vma450_liquidcrystal_i2c_library.zip

Best Regards
Velleman Support

After looking and trying, I finally found it. The VMA450 library has the same name as another LiquidCrystal_I2C.h.
So, I went to my laptop which hasn’t Arduino installed. Installed it and, yep… The same error. This was because the LiquidCrystal_I2C library was already added by default. I changed the LiquidCrystal_I2C.cpp and the LiquidCrystal_I2C.h to LiquidCrystalVma.cpp and LiquidCrystalVma.h.
Internally in both files, I changed all functions and classes from LiquidCrystal_xx to LiquidCrystalVma_xx and changed the names from both files to LiquidCrystalVma…
After that, I added all files to a folder (vma450) and imported it to Arduino (or, in my case visual studio 2022 with vMicro). Close all apps like Arduino ide or visual studio and start them again and you will see a new library LiquidCrystalVma.

On Arduino Mega, just connect the sda and sdl to to sda and sdl outputs and it should work!

Thanks for your support!