16 x 2 display starts only after reset

Forum 2005-2010 (read only) Hardware Troubleshooting
1

Hi, I have the following problem that repeats itself on different boards.
The problem exists regardless of the power source (USB, external).
When the power is on the LCD doesn't start before I depress the
re-set button a couple of times.

The setup is simple - I tried to minimize the number of wires so
I used 4 data wires and I grounded the 5-th pin of LCD as
suggested in some manual.

The LCD related strings of code look like follows:

#include <LiquidCrystal.h>
LiquidCrystal lcd(12, 0, 13, 4, 7, 8, 9);

void setup()
{
...
lcd.clear();
...
}

void loop()
{
lcd.setCursor(aaa,bbb);
lcd.print("ccc");
}

"LCD doesn't start" means that the code and the board are definitely running (there are sound and light indicators that behave exactly like
they are supposed to do) but there's no sign of anything on the display.
(The LED is on, the contrast is set by the potentiometer.)
After the LCD has finally started to operate it doesn't go back
to blank screen regardless of the resets or code uploading.

Thanks for the ideas.

2

OK, it goes without saying that the rest of the "regular" wires like power and ground are soldered to LCD :slight_smile:

3

Try updating your LiquidCrystal library. I found I had the same problem - the LCD would not init properly until I reset the Arduino. The update solved it.

The updated version is here:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1246900100

4

OK, thanks a lot - most probably, it's the case.

5

you were right - updating the library has solved the problem.
Thanks again.