I need some advice as I have tried everything I know to no avail. I connect 1 1602a lcd as per instructions on web site and it works perfectly. I connect the 2nd lcd and only partial data shows. Now some of the data on the first lcd is incorrect. When I remove the second lcd the first is again correct. I have switched lcds and the same thing happens.

I have a 2 amp power supply for the Arduino 2560 and powering the backlits with a separate USB power.

I don't know what else to do and have been trying different things for weeks. I need some ideas.

in SimVimCockpit by

1 Answer

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Hi Joey,
on which pins do you have LCD1 and LCD2 (LCD control pin) connected to the Arduino2560?


Frank, It's absolutely  doesn't matter what pin you use for signal line.
It can be pin #3, 12.. as well as 60.. 69  (A..A15), there is no any difference for the program code.


Please read the reworked powering/ground page again, maybe it will help. Take a note below about grounds.


By the way, find the paragraph with " ...  it's pointless to use a high-power source to feed the Mega2560 board through the power jack ... "