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LCD 16x2 not working
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Please be positive and constructive with your questions and comments.

Re: LCD 16x2 not working

by adafruit on Wed Sep 09, 2009 2:22 pm

do some tests on the pot using a multimeter. it may be faulty...

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Re: LCD 16x2 not working

by cclaver on Sun Sep 13, 2009 4:11 pm

Success!!!

I ordered a replacement display from adafruit and all is well. Simply swapped the suspected bad display for the new and...
Presto! it works.

The 10k pot measured out OK. I suspect that the display unit doesn't want see anything close to a short between Vo and VDD. This is the state with my wiring when the pot is fully counter clockwise. This basically puts VDD on the Vo pin, which I don't think the display module appreciates.

Now, on to other Arduino adventures...

CC
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Re: LCD 16x2 not working

by yosup on Sun Jan 10, 2010 6:16 am

Hi All,
I'm strugle with LCD 16*2, same situation with CClaver. CClaver found solution with replacing display module.
But, My case is not working with 4 different display same. IDE version 0017, LCD library is updated.
Just upper rail 16 box shown with potentiometer control.

Code is below.

Code: Select all | TOGGLE FULL SIZE
#include <LiquidCrystal.h>

LiquidCrystal lcd(7, 8, 9, 10, 11, 12);

void setup()
{
lcd.begin(2, 16);
lcd.setCursor(0,0);
lcd.print("hello, world!");
}

void loop()
{
}
Re_SDC10210.JPG
LCD wiring
Re_SDC10210.JPG (344.79 KiB) Viewed 2277 times


Multimeter check result are below.

Arduino side
Pin 12, 0V
11, 4.86V
10, 0V,
9, 4.96V
8, 0V
7, 4.96V



any comments welcome!
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Re: LCD 16x2 not working

by floresta on Sun Jan 10, 2010 1:29 pm

Yosup:
lcd.begin(2, 16);
This is backwards.
lcd.setCursor(0,0);
This is not required.

Try using the Hello World example that comes with Arduino v0017. Cut and paste it so you don't introduce any typos. The example code in the playground is FUBAR.

The multimeter readings don't mean much on varying digital signals except that you could check that you get the same reading at the other end of the wire, at the LCD module. You might want to verify that RW (pin 5) is at 0 volts. Your wiring looks OK but there could be a bad connection somewhere. I have some nearly new but inexpensive breadboards that give me problems sometimes.

Don

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Re: LCD 16x2 not working

by thomsirveaux on Wed Jan 20, 2010 4:47 pm

I'm having a similar problem.

I can get the backlight and contrast control to work, but nothing will output on the screen.

I've checked and rechecked the wiring, had friends check the wiring, etc. The only thing I can think of that would cause this problem is it's not outputting, or if it is, it's not initializing the display properly.

Or am I just crazy?

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Re: LCD 16x2 not working

by adafruit on Wed Jan 20, 2010 6:08 pm

you could try posting a nice clean photo and what code you're trying to use

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Location: nyc

Re: LCD 16x2 not working

by thomsirveaux on Thu Jan 21, 2010 4:45 pm

Wait! Got it working!

Forgot to pull the R/W pin to ground . . . but for some reason, I thought it would do it automatically.

*Durp, durp, durp!*

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Please be positive and constructive with your questions and comments.