LCD Issue: Shows Nothing but 2 rows of 20 squares on each row.

Other Hardware Displays
1

LCD Issue: Shows Nothing but 2 rows of 20 squares on each row.

Hello al, i am hoping that someone can assist me with what to do next on this issue.

My Specs:

  • Printer i3 reprap
  • Card=Mega 2560
  • Processor=ATMega2560
  • Port=3
  • Programmer "AVRISP mkll"
  • USB connection=USB2.0
  • O/S=Windows 10 - 32bit

When first setup, the LCD showed all settings and instructions and was doing what it should, however during the firmware upgrade i lost all data and ended up with only the squares. _ See attached Photo

Things i have tried!

Researched topics on this problem type on this forum and on Google with no luck. ...So much Research...
Updated to the latest Arduino 1.6.6 - Also tried other earlier versions.
Tried Repetier Host firmware
Re installed Arduino 1.6.6
Been back and forth through the troubleshooting guide and followed all applicable steps.
I have tried updating the card with nothing else plugged in.
I have tried resetting the card using the reset button on the card itself.
I have moved from USB3.0 to USB2.0

I have managed to run the "Blinking" example as advised in the instructions, and confirmed upload of the sketch with no issue, except that nothing shows on the LCD.

Any help on this matter would be greatly appreciated. Just FYI , although i am very computer literate my coding skills are poor at best. may i ask that you please be as instructive and in depth as you can in any processes you wish me to follow in helping find a solution to this issue.

Many Thanks Chrisgo :slight_smile:

2

Adjust the potentiometer.
If the LCD has an 12C backpack, adjust blue block component.
Turn in both directions to check if the characters display.

3

You are assuming that we know what you are talking about but you haven't explained such things as:

  • why you are using an AVRISP programmer with Arduino 1.6.6
  • what settings and instructions the LCD showed (or what that even means)
  • what 'Repetier Host firmware' refers to
  • what troubleshooting guide you are using
  • what card you have updated and reset
  • what Blinking example you tried and what instructions it appears in

If you really researched your problem on this forum then you would have learned

  • what the presence of the two rows of blocks signifies
  • what your photo (which wasn't attached as advertised) should show
  • that we also need to see your program code

Don

4

Hi Aisc thanks for your help.

You mentioned Adjust the potentiometer.
If the LCD has an 12C backpack, adjust blue block component.
Turn in both directions to check if the characters display.

I'm not quite sure what the potentiometer actually is? If you are referring to the small blue and white button on the back of the LCD display then i have tried to adjust that and all it does is make the squares all white or fainter to the point of disappearing. The blue block component is soldered to the board and does not turn at all., only the white button here is a link to a photo of the thing i think you are referring too. Please correct me if i am wrong !
https://www.dropbox.com/sc/re802laclnztal5/AAAHoSn5HFnvarTfsVIXhyd_a

5

Hi Floresta Thanks for the guidance

You are assuming that we know what you are talking about but you haven't explained such things as:
No assumptions just a simple lack of understanding on the subject matter
In answer to your questions:

  1. why you are using an AVRISP programmer with Arduino 1.6.6 This is where i got the idea that the controller was the correct one as it was the default. If this is incorrect can you please advise me of the correct controller to use? Default Controller possibly incorrect

  2. what settings and instructions the LCD showed (or what that even means) - The normal characters that show up on a normal working screen showing the temp and other settings for the printer, i hope i have clarified this enough for you to understand what i meant!

what 'Repetier Host firmware' refers to I do apologize i meant the The repetier host program not firmware - My bad! :slight_smile:

what troubleshooting guide you are using This One Guide/Troubleshooting
what card you have updated and reset Sorry Board not card - This one Board i was referring too
what Blinking example you tried and what instructions it appears in This example Blink Sketch and the Step-by-step instructions for setting up the Arduino Software (IDE)

If you really researched your problem on this forum then you would have learned Researching and understanding are 2 very separate things. I seek to understand what i researched

what the presence of the two rows of blocks signifies - My research showed various posts mentioning different problems with the same issue for example one post was in regards to squares only showing on one line. Another post referred lines that only had squares on part of the display. Another referred to the same issue but with different boards eg Uno v Mega, it was all extremely confusing for a novice to the entire rep rap world, especially when the understanding of the differing boards and software firmware was taken into account. EG marlin V Arduino
what your photo (which wasn't attached as advertised) should show That was my mistake and my unfamiliarity with the blogging software. My apologies here are the photos i meant to send. The Issue I am Having My Setup
that we also need to see your program code The only code i can think of that you are referring to is the code in the sketch example which is as follows.

void setup() {
  // put your setup code here, to run once:

}

void loop() {
  // put your main code here, to run repeatedly:

}

Any help you can offer would be greatly appreciated. Thank you for replying to my cal for help and i hope i have given you the information you requested. I have placed my answers in a different color for easy reading.

Chrisgo :slight_smile:

6

The potentiometer adjusts the brightness of the characters, so u are adjusting the correct component.
If u see rectangular dark blocks, u may need to adjust.

Post a link to your actual LCD module you have.

Your code should look something like this :

#include <Wire.h>
#include <LCD.h>
#include <LiquidCrystal_I2C.h>

// #define I2C_ADDR     0x27
// LiquidCrystal_I2C lcd(I2C_ADDR);

LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, NEGATIVE);

void setup()
{
  Serial.begin(9600);
  lcd.begin(16,2);
  }

void loop()
{
    Serial.println("Hello ais");
    lcd.backlight();
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("Hello ais.");
    delay(3000);
    Serial.println("The LCD works.");
    lcd.setCursor(0,1);
    lcd.print("The LCD works.");
    delay(3000);

    lcd.noBacklight();
    delay(5000);
    lcd.backlight();
    delay(5000);
    lcd.noBacklight();
    delay(3000);
  }

The above code works with my LCD's, it may or may not work with yours.
Check the names of the libraries you have installed.

7

Thanks Aisc i found the potentiometer but that's not the issue. I can see the squares fine, but as i have just blown up my board ill kill this thread and start again when i source a new board. :slight_smile: Thanks for your help it was much appreciated.