Hello Marcolino,
Have a look at Application Note AN2940, "LCD Driver for the HC08/HCS08 Family", and the associated software file. It covers both 4-bit and 8-bit interface modes for LCD displays based on the HD44780 device.
Regards,
Mac
I wouldn't be surprised.
3. Contrast Level (you will amaze with how many people have a perfectly working LCD and Software, but fail to put the correct contrast level to see the characters).