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Topic: 1602a 16X2 LCD is blank (Read 7 times) previous topic - next topic

afremont

It looks like Vss is not connected in the picture.  There doesn't appear to be a jumper in the hole above the pin on the display board.  Even before doing any initialization, the OP should be seeing rows of black squares if the power is ok and the the contrast is good.
Experience, it's what you get when you were expecting something else.

floresta

#16
Feb 02, 2013, 09:59 pm Last Edit: Feb 02, 2013, 10:05 pm by floresta Reason: 1
Quote
It looks like Vss is not connected in the picture.  There doesn't appear to be a jumper in the hole above the pin on the display board.

That's due to what I mentioned about parallax and the reason for the recommendation to use a long lens.

Quote
Even before doing any initialization, the OP should be seeing rows of black squares if the power is ok and the the contrast is good.

I wish I had thought of that.

Don

afremont


Quote
It looks like Vss is not connected in the picture.  There doesn't appear to be a jumper in the hole above the pin on the display board.

That's due to what I mentioned about parallax and the reason for the recommendation to use a long lens.

Quote
Even before doing any initialization, the OP should be seeing rows of black squares if the power is ok and the the contrast is good.

I wish I had thought of that.

Don


Ok, you caught me.  I didn't read it all carefully, I see now where you mentioned the boxes and contrast. 
Experience, it's what you get when you were expecting something else.

ttexan

I just read all of this thread and I am having the same problem.  I can get the squares and adjust them to very light.  However, I do not get any signals (words).

See attached picture.

floresta

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I just read all of this thread and I am having the same problem.

That looks like a unique display.  Can you give us more information about it?

We can't really verify that your connections are correct without being able to unambiguously follow each wire from one end to the other.
 

Don

ttexan

As far as I know it is a standard display.  I have attached a photo of the back as well as a better picture of the overall setup and a close up of the LCD wiring.

floresta

It looks like you may have now have pin 5 of the LCD (R/W) connected to +5 instead of GND.  It appeared to be correctly connected in your original photograph.

Don

ttexan

You are absolutely right.  I must have switched it when I cleaned it up for the last photos.

OK, I put 5 to GND, but nothing changed.  If I look really hard at the display I can almost see some movement where the letters should be.  This may just be my imagination as I cannot bring it out with any changes in contrast.

I know the last thing to suspect is always the hardware, but I am beginning to think that the LCD might have a problem. 

Dan

ttexan

My face is red!  I thought of one more thing so I checked my software and discovered I had it set up for Arduino Uno and not Arduino Mega.  I had switched to another project and forgot to change back.

LCD is now working.

A real NOVICE error but then again that's exactly what I am.

Thanks for the help.

Dan

AMPS-N

I am also having same Problem , any one solve issue for above
AMPS

floresta

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I am also having same Problem , any one solve issue for above

I thought he did solve his problem as reply #23 states "LCD is now working".

Start a new thread for your problem since this one is almost a year old and is solved.  Be sure to indicate exactly which display you are using, include your program code, and provide a photograph of your setup if possible and you will get all kinds of help.


Don


jmsl100

Hello, you are powering the circuit only with 3.3 Volts, try in 5 volts and it works fine.
Other problem was your solderings, try to appear bright and smooth like D5 pin in the LCD, do not permit the holes, you just need to use a small quantity of soldering paste at the tip of the iron. And try to mantain the iron tip clean.
And by the way the code was pretty good. Simple and efective...

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