Most displays have adapter circuitry, however.

While the display itself may be output only, the adapter circuitry seldom is. I realize that there are numerous devices on the market that partially emulate the "conventional" LCD, those devices that don't allow reads, generally, to apply your license, aren't really LCD's.

The typical LCD works pretty much like the HD44780, and many VFD's and others, pretty closely emulate that. However, the O/P, who's lost interest because of all the argument over nothing germane to the discussion, did, after all, indicate he was using an LCD, and not a VFD, LED, or whatever.

What's sad here is that if the O/P had been just a bit more specific, including the manufacturer and conntrol IC of his LCD, he'd probably have gotten his requirement met right away. As it stands, he got nothing.

RE