I will report my two last days because I forgot to post every day.
My last update was about trying to initialise the LCD controler. It’s finally check. Now I can display two messages on the first line at one frequency and two other messages on the second line at another frequency.
I can also use the push button to change the intensity of the LCD screen.
Then I had to initialise xbee module. I had a stupid problem during about 1h. I finally found it, that juste was a bad pin configuration.
I can play music with frequency values from xbee messages.