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Topic: Problem with allignment of LCD (Read 2109 times) previous topic - next topic

guyspronck

Hello there!

Got my arduino this weekend and started playing around with it and I enjoy it alot. Programming is not too hard as I am studying IT. I got a lcd aswell, it was not to hard to get setup (had to solder pins too it though).

But now I got this:
On the upper row of it starts too high placing the text (1 pixel), this is not a big deal as all text will fit onto it. But on the second row it pushes the pixels up one and pieces of the text fade/fall away. Most of the time with CAPS but some times with normal letters. It also looks like it doesn't use all the pixels it can use (could be wrong here).

To show what the problem is, here are some pictures:
https://www.dropbox.com/s/ag5do0mkytlkyqa/lcdPixels1.jpg
https://www.dropbox.com/s/1yipl0rratirmmt/lcdPixels2.jpg
https://www.dropbox.com/s/6il3z79j5vv1y4p/lcdPixels3.jpg

Hope you can help me out!

Thanks in advance,

Guy

floresta

Quote
Hope you can help me out!

You will have to help us out a bit first.

We have to know what type of LCD you are dealing with.

We have to know what program code you are using.

We have to know how your LCD is interfaced with your Arduino.


Don

dhenry

It is defective: the 2nd line should have shown its top row, as the 1st line did.

guyspronck


It is defective: the 2nd line should have shown its top row, as the 1st line did.


There are 2 lines missing then, on the bottom row. Could this be a bad connection on the pins? I soldered them myself so it could be.

dannable

See reply number one (post number two!). If anyone can sort it out for you Don can.
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guyspronck


Quote
Hope you can help me out!

You will have to help us out a bit first.

We have to know what type of LCD you are dealing with.

We have to know what program code you are using.

We have to know how your LCD is interfaced with your Arduino.


Don


It's a 1602a LCD, it doesn't say more on the lcd.

Here is my code:
Code: [Select]
/*
lcdSetup - Guy
Basic setup for a LiquidCrystal display


Connections:

RS = 12
RW = 11
E  = 10
D4 = 6
D5 = 7
D6 = 8
D7 = 9

A = 5V   (+)
K = GND  (-)

VDD = 5V  (+)
VSS = GND (-)
V0 = PotMeter Middle Pin

PotMeter:
Right Pin = 5V  (+)
Left Pin  = GND (-)

*/
#include <LiquidCrystal.h> //Include the LiquidCrystal library

LiquidCrystal lcd(12, 11, 10, 6, 7, 8, 9); //Setting a LiquidCrystal as 'lcd'
void setup()
{
  lcd.clear(); //Clear the display
  lcd.begin(16,2); //Define the Length and Rows
}

void loop()
{
  lcd.setCursor(0,0);
  lcd.print("Hello forums!");
  lcd.setCursor(0,1);
  lcd.print("Pixels MESS up");
  delay(100000);
}


Here is a pic of the setup:
https://www.dropbox.com/s/77mj452jl205gev/lcdPixels4.jpg
Note: This is a slightly different pin allignment then I now use. But it did the same thing.

I also tried using all data pins, didn't change anything.

dhenry

Quote
There are 2 lines missing then, on the bottom row.


The bottom row is for the underline / cursor. The font itself is 5x7. Check the datasheet.

dhenry

Quote
I also tried using all data pins, didn't change anything.


It has nothing to do with external connections.

The lcd is toast.

guyspronck


Quote
I also tried using all data pins, didn't change anything.


It has nothing to do with external connections.

The lcd is toast.



Damn that, ordering a new one then. Any good places to get one?

floresta

#9
Dec 11, 2012, 05:12 pm Last Edit: Dec 11, 2012, 05:20 pm by floresta Reason: 1
Quote
It's a 1602a LCD, it doesn't say more on the lcd.

That's enough to get started.

Quote
Damn that, ordering a new one then. Any good places to get one?

I wouldn't give up yet.

A character mode LCD like the one you have does not have to be refreshed.  Therefore the code that you have in loop() should be in setup() and loop() should be blank.

But lets go back a step.  What happens when you connect just the backlight, the power, and the contrast (pins 15, 16, 1, 2, and 3)?

Back one more step - are you using a resistor in series with either backlight lead?


Don

Khalid

Your LCD is good, dont scrap.
Just measured the output voltages of the Arduino input to the LCD. and tell what voltage at what pin you are getting wrt gnd. I think one of your arduino pin out has low voltage (any led, resistor you added)
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guyspronck

Quote
But lets go back a step.  What happens when you connect just the backlight, the power, and the contrast (pins 15, 16, 1, 2, and 3)?

Did this, when I put the contrast all the way up only the top row changes contrast. The bottom one doesn't.


Quote
Back one more step - are you using a resistor in series with either backlight lead?


I am not using a resister in series with either of the backlight lead, is this needed?

dhenry

Quote
Any good places to get one?


Tough to know in your backyard but I got mine (48 of them, in one box) years ago from digikey.

floresta


Quote
But lets go back a step.  What happens when you connect just the backlight, the power, and the contrast (pins 15, 16, 1, 2, and 3)?

Did this, when I put the contrast all the way up only the top row changes contrast. The bottom one doesn't.

That is exactly what is supposed to happen.  Most likely your LCD is not defective but personally I wouldn't absolutely declare it good or bad based on what I know so far.

Quote
Quote
Back one more step - are you using a resistor in series with either backlight lead?


I am not using a resister in series with either of the backlight lead, is this needed?

These backlight LEDs always require some sort of current limiting.  Sometimes there is a resistor on the pc board, but most of the time you need an external one.  I would start with 150 ohms and see what happens. 

Without this resistor you could damage the LEDs but it is more likely that your power supply is not capable of supplying enough current to do so.  In this case it's output voltage could be dropping and this could possibly be causing the LCD to malfunction.


Don


guyspronck

Quote
Without this resistor you could damage the LEDs but it is more likely that your power supply is not capable of supplying enough current to do so.  In this case it's output voltage could be dropping and this could possibly be causing the LCD to malfunction.[/color]


I put a 1k resister on the backlight and this fixed only the first character. Don't know what it could be really.

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