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By Pryankster
I've got an Arduino (on a Modern Devices' BBB) hooked up to the Nokia knock-off display and break-out board from SF.

I've been able to get the ARduino to talk to the LCD, but only very slowly. I have to insert 72 NOP instructions between bit twiddling or the display does not respond. With the NOP instructions, the writes seem reliable, but slow (takes about 5 seconds to fill the screen with a solid color)

As far as physical connections, I've got it wired up on a solderless breadboard, I'm feeding the BBB through a 3.3v regulator (vs. the 5v that it's normally rated at). The wires between the BBB and the LCD are not excessively long (about 3.5"). The only other hardware attached is an LED on Arduino pin 13 to watch code uploads.

I wonder if the problem could be too low of a voltage on the ATMega? I've also read that the LCD is pretty susceptible to noise ..

Disclaimer: I'm a software guy ... be gentle :-)

-- pryankster
By koolatron
Your problem could very well be reflections. My guess is that the first write is getting done just fine, but all the subsequent writes are corrupted by reflections from the previous ones. Slowing down the writes of course clears things up, but... makes things slow.

Try terminating with a couple of 50-ohm resistors.