Problems with lcd (tianma TM162AD)

Has anyone else tried to use this lcd? I've tried both LCD4Bit and LiquidCrystal examples, and nothing works. The only change is when the program starts (or I press the reset button) where the display changes from blocks to lines (bottom row of each block) briefly, and then changes back.

Here's the description:

Thanks in advance... Margrave

The datasheet says the controller is supposed to be HD44780-compatible. But (purely a wild guess) maybe there are some peculiarities (perhaps in the way it maps RAM addresses to screen cells?) that make it not exactly so.

Or maybe the unit you got is defective.

My suggestion: first, compare the datasheet to the one for the 44780 for peculiarities like differences in initialization sequence or memory mapping. Also double-check the module pinout to make sure it's not non-standard. If it's backlit, make sure you don't need to add an external current-limiting resistor: maybe it's screwing up the power supply.

If possible, set up the Arduino with a known-good 44780-based display, and make sure it's working, to eliminate the possibility of wiring errors. Then swap in the Tianma display, and check it against a setup you've tested good.

Hope this helps,