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Topic: LCD 16x2 is not display anything (Read 2376 times) previous topic - next topic

hidayah

hye there... i have buy lcd and arduino uno... i had wiring it... but only black box appear in lcd...

after i burn the coding in arduino using IDE... nothing happen... can u see what the problem?

Paul__B

#1
Oct 28, 2013, 09:52 am Last Edit: Oct 28, 2013, 09:56 am by Paul__B Reason: 1
I think you need to connect some wires to convey data to the display.

...

From the Arduino.

floresta

#2
Oct 28, 2013, 01:23 pm Last Edit: Oct 28, 2013, 01:30 pm by floresta Reason: 1
@paul
That's not even his set-up.  The picture is from the Lady-Ada tutorial (http://learn.adafruit.com/character-lcds/wiring-a-character-lcd).

Quote
can u see what the problem?

Did you follow the rest of the steps in that tutorial?

Don

xianwu

mine not display anything too.
the code is from arduino example
http://arduino.cc/en/Reference/LiquidCrystalConstructor

Code: [Select]
#include <LiquidCrystal.h>

LiquidCrystal lcd(12, 11, 10, 5, 4, 3, 2);

void setup()
{
  lcd.print("hello, world!");
}

void loop() {}


I'm sure I wired it right,  after upload, power cycle board. nothing showed up

bperrybap

xianwu,
The example code on that constructor page is wrong.
It is missing the begin() call to initialized the LCD in the setup()
function.

I'll report the bug/issue to try to get them to update the web page.

See the example code on the tutorial page:
http://arduino.cc/en/Tutorial/LiquidCrystal
for an example of how to use the begin() function.


--- bill

xianwu

thank you Bill, I try your example. still nothing showed. I wonder if my LCD is Hitachi HD44780 (or a compatible) chipset.
I do see 16 DIP pins, see my picture, pin1 GND,   pin 15, 16 backlight .(I apply voltage at pin 15, 16, LCD lights up )
but nothing show up.
How could I determine it's Hitachi HD44780 (or a compatible) chipset.?
or Is there any advice?

thanks

MAS3

Where did you get that display ?
Is there any text printed on the board (and what is it ) ?

Identifying the display is the first thing to do.
Have a look at "blink without delay".
Did you connect the grounds ?
Je kunt hier ook in het Nederlands terecht: http://arduino.cc/forum/index.php/board,77.0.html

xianwu

it says MTC-20200B made in Taiwan.
I found MTC-20200X datasheet.

and 16 pin is same as arduino's example. the only diff is pin 3. in arduino pin3 is contrast, but
MTC-20200X datasheet.


pin 2   VDD                        Logic Circuit Power Supply
pin 3    VO                       Power Supply for LCD Panel

any advice?

bperrybap

from looking at your photo, I see no potentiometer.
What is the brown wired connected, on the arduino end it looks
like it is connected to 3v?

Can you take some closer photos of your Arduino and LCD
so we can see where all the wires are connected and see
the connections and sholder joints?

--- bill

xianwu

you are right bill. I connect 3.3v to pin 3.
thanks for check. here is picture


xianwu

bill,
the brown wire connects Arduino GND, ----> LCD pin5 R/W
the grep wire  Arduino 3.3V ---> LCD pin3 Vo

and this LCD is 20x2 chars. let me change lcd.begin(20,2), see if make any diff.

thanks

Xianwu

xianwu

lcd.begin(20,2) still won't work.

Paul__B

Slightly unusual board then, but no matter.

Pin 3 goes to a potentiometer to set the contrast, something like 10k to 50k, which is powered from Vcc (+5V) and ground, but the wiper will need to be set very close to ground.  It is usually appropriate to approximate this with a pair of resistors with say 22k from pin 3 to Vcc and 2.2k from pin 3 to ground.  (The exception is if it happens to be a special "extended temperature" version, but it most likely is not).

The fact that the display shows nothing, not even the set of "blocks", tells us that you are not setting the necessary contrast voltage on pin 3.



xianwu

I thought contrast voltage could be any between 5V--0V so I just connect it to 3.3V.
let me try a 10k  potentiometer.

xianwu

cheer!

thanks Paul__B

I saw "hello world" with 22K, 2.2K .

but  too dim.

I connect pin 15 to 5V pin16 to GND, then perfect!

thank you all for  helping.

xianwu

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