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Topic: 16x2 LCD shows only black boxes in the bottom line (Read 18699 times) previous topic - next topic

jay2012

nothing happened when i turned it over before...it was still the same.

floresta

#16
Oct 14, 2012, 03:55 pm Last Edit: Oct 14, 2012, 03:58 pm by floresta Reason: 1
Quote
nothing happened when i turned it over before...it was still the same.

No it was not the same, unless you have a very unusual display.

Don

jhashmi

i know this topic is closed but many of will coming here with the same problem
i was facing this problem too and just find out why it was.
one thing is very clear that you are watching lcd up side down
as i was doing too. and second thing that led is not being communicated.
in my case i didn't conected the r/w to ground by connecting its working properly

floresta

Quote
in my case i didn't conected the r/w to ground by connecting its working properly

You obviously have looked at some old threads but you haven't gone back far enough.  The problem of not connecting the R/W line was quite prevalent several years ago but has only shown up one or twice in the past few years.  The connection is clearly shown in the diagram with the tutorial (http://arduino.cc/en/Tutorial/LiquidCrystal) and is also mentioned in the program comments.


Don

BlackT

hello, i know the topic is old but i have a strange problem.
I conect my LCD like this
 http://fritzing.org/media/fritzing-repo/projects/h/how-to-connect-a-qy-1602a-lcd-to-arduino-correctly/images/conectar%20un%20lcd%20qy-1602%20a%20un%20arduino%20uno%20r3_bb.png
And when I conect my USB cable and upload sketch the LCD works, but when I unplug the USB then plug it again it just show the first black row. When I upload sketch it work again

/*
  LiquidCrystal Library - display() and noDisplay()

 Demonstrates the use a 16x2 LCD display.  The LiquidCrystal
 library works with all LCD displays that are compatible with the
 Hitachi HD44780 driver. There are many of them out there, and you
 can usually tell them by the 16-pin interface.

 This sketch prints "Hello World!" to the LCD and uses the
 display() and noDisplay() functions to turn on and off
 the display.

 The circuit:
 * LCD RS pin to digital pin 12
 * LCD Enable pin to digital pin 11
 * LCD D4 pin to digital pin 5
 * LCD D5 pin to digital pin 4
 * LCD D6 pin to digital pin 3
 * LCD D7 pin to digital pin 2
 * LCD R/W pin to ground
 * 10K resistor:
 * ends to +5V and ground
 * wiper to LCD VO pin (pin 3)

 Library originally added 18 Apr 2008
 by David A. Mellis
 library modified 5 Jul 2009
 by Limor Fried (http://www.ladyada.net)
 example added 9 Jul 2009
 by Tom Igoe
 modified 22 Nov 2010
 by Tom Igoe

 This example code is in the public domain.

 http://www.arduino.cc/en/Tutorial/LiquidCrystalDisplay

 */

// include the library code:
#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(11, 12, 7, 6, 5, 4);

void setup() {

  // set up the LCD's number of columns and rows:
  lcd.begin(16, 2);
    // Turn off the display:
    lcd.setCursor(5,0);
  lcd.print("HONDA");
  lcd.setCursor(4,1);
  lcd.print("CRM 180");
  delay(2000);
  lcd.clear();
  lcd.print("H:xxxx.x");
  lcd.setCursor(0,1);
  lcd.print("km:xxxxx");
  // Print a message to the LCD.
 
}

void loop() {
    // Print a message to the LCD.

 
}


I use arduino nano clone 328

floresta

Quote
hello, i know the topic is old but i have a strange problem.
Then start a new thread.

Post a photograph of how you actually connected your components rather than a link to a site that shows how you are supposed to connect things.

Check your link to verify that it works, yours doesn't.

Use the 'code' button to correctly display your code.  Read the forum instructions if you don't know how to do this.

Don

BlackT

On extrenal power it is working OK, so is somethnig about when computer is looking for arduino hardver, never mind it will work on extrenal power, problem solved :)

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