Hi.

I've been using a VFD with a micro interface like many LCDs.
We learnt several things:
1. Takes a few 100 ms to get ready to read
2. Most actions are a few us but it was quicker to write a screen full of spaces
 than to
use the Clear Display command.
3. The display will flicker if you repeatedly write characters to the screen.
        Dots that are off have no problem, but when they are on they do.
        Even if the characters stay the same, the intensity dips.
        Probably not noticed on LCDs though.
4. It was a real pig to ensure getting into the right mode (4-bit).
        You can't guarantee which mode it starts up in, so you need a procedure
        that gets to the mode you want from either mode.
5. I really wish the original designer had used 8-bit interface.
        This speeds up data transfer, and opens doors for optimisation.
        You could always have the high-nibble bits doing double duty.
        Keep the bit order clean. Saves many code bytes!