I just got done building my second prototype with a 44780 driver, and I
swear the first one tri-states only when E and R/W are BOTH low (I tested
this by measuring the pins as I switched R/W) and the second one doesn't
tri-state even when they are both low.  The boards and the chips on them
are exactly the same, except one has a Phillips 22V10 and the other an
AMD.

Anyone have an explanation?  I'll be working on these boards for the next
few days, so I'll keep you posted on my efforts.  I'm hoping to find I've
gone brain dead somewhere, but right now it seems unlikely.

                        Don