Heu ... I'm only working with isis .... I'll try with my arduino later.
I agree with you for the pull-up from the lcd. So I suppose I have to modify the value of the ds pull-up. But wich value ?
I tried some values but nothing works.
Perhaps for making it more simple, if I disconnect the lcd and connect the led (in place of pin d13). It's also not working.
ps : for the led connected on d13, there is no problem. The lcd works fine. In fact I make like this because it is the way the arduino uno is made (see http://arduino.cc/en/uploads/Main/Arduino_Uno_Rev3-schematic.pdf).