Hi all!
i bought a nice Raystar LCD modul for my minimalSID synth.
http://www.tme.eu/en/Document/8edbea480ac602455d604e39dfe07a51/RC2002A-BIG-ESV.pdf
///Interface Pin Function at page 6
can i use this with a PIC based core if the LCD Vdd is 3.3V and the pin 16 is NC/not connected?
Not by default no as the PIC Core operates on 5V. You will need to build a level conversion circuit with for example a 74HCT541.
Yes!
If you don´t want to use an IC, and have a few resistors lying around, that might work, too:
As the data lines on the LCD end are only receiving data, you don´t need bi-directional level shifting and also as no high currents flow, it is possible to also build that with voltage dividers (two resistors per data line). You can get 3.3V supply voltage for the display by using a LDO voltage regulator (fed by 5V, outputting 3.3V).
Many greets!
Peter
PS: Great avatar, PickNick! Good old times! 
thanks!
i have a few 3.3V regulator…of course:)
…but i still don’t know what about the pin16 on the LCD
which is NC on the datasheet…
cheers!
Peter
Looking at the datasheet, i´d say no need to connect pins 15 and 16.
These are normally the supply pins for the display backlight. I think this special model has an inverter or something like that onboard, especially as pin 15 is described as “negative voltage output”.
The worst thing that can happen when you don´t connect the pins, is that you have no backlight (but should see characters).
The worst thing that can happen, if you connect them (especially as pin 15 is described as negative voltage output) is the release of some awesome amount of magic smoke! 
Many greets,
Peter