Help with E-paper diaplay

Using Arduino Displays
1

Hi all.
I am starting with E-paper display.
I got a 2.9" display from 'buydisplay' and loaded one of example. It works OK.
However, being new to arduino, I find difficult to understand the commands used in the example.
In fact I have looked at many exsamples with out any joy.
Is there a list of commands for E-paper display?
I would like to make a simple four digit counter that is update when you press a button. I can do the I/O but cannot do the display.
Thank you for your help.
Regards

2

Please post the working example sketch, using code tags when you do

The source code of whatever library that you are using will be on your PC and can be viewed to see which functions are available

3 

#include <GxEPD2_BW.h>
#include <GxEPD2_3C.h>
#include <Fonts/FreeMonoBold9pt7b.h>
#include "GxEPD2_display_selection.h"
int number=0;
void setup()
{
  display.init();
  helloWorld();
  //display.hibernate();
 }

void helloWorld()
{
  display.setRotation(1);
  display.setFont(&FreeMonoBold9pt7b);
  display.setTextColor(GxEPD_BLACK);
  display.setFullWindow();
  display.firstPage();
  do
  {
    number= number+1;
    String myStr=String(number);;
     
   
    display.fillScreen(GxEPD_WHITE);
    display.setCursor(50, 50);
    display.print("This is number: ");
    display.print (myStr);
    
  }
  while (display.nextPage());
}

void loop()
{
  
}

This the code I managed to write.
Ithink I need a 'Partial Refresh'. But i got confused when i looked at many example.
Thank you for your help.
Regards

4

@Francesco2017, Hi, welcome back to the forum!

Maybe it is time for you to read (once again) How to get the best out of this forum.

Now we know which library you use. But we don't know which display you selected.

And we need to know the exact display you have; please post a clickable link.
And tell which processor/board you use and compile for.

Your code looks ok, but maybe your display panel is not supported by GxEPD2.
The panel usually has some inking on the flex connector. Please report it, then I can compare to the panels I have.

The list of methods can be found in the header files of GxEPD2 and in Adafruit_GFX.h

Jean-Marc

BTW: You will get garbage (scrambling), if you print a value that is changed inside the page loop. Every run through the loop needs to print exactly the same!

5

Hi, thank you for the reply.
The display seems to be working correctly.
I can display text and change colour.

The display is ER-EPM029-1 from buydisplay.com.
I am using an Arduino Nano v3.
The example I used to verify the display is from library "GxEPD2_GFX_Example" by Jean-Marc Zingg.
It displays Text in Red and Black. Screen rotation and partial refresh.
Do you think i should try something else?
Regards

6

Thanks for the information you provided. I don't see your problem, so it is of no importance for me that you didn't provide all information I asked for.

7

HI.
The problem is that my that my code does not update the display with the counter.
I cannot find out why.
I cannot extrapolate what to do, when looking at the many examples I have tried.
Regards

8

So, post your code that does not update the display and we can compare it with the working example

9

Does the library you are using have a 'Keywords.txt' file? I don't have an E-ink display, or that library, so I don't know if it does, but it's worth looking.
Also, have you googled it?

10

Hi, and thank you for the reply.
The code is at the begin of this thread.
The code does print text correctly and the number next to it.
What i cannot do is update that number only, without refreshing the entire screen.
I cannot understand any of the example for Partial refresh (i think that what i need in my code).
Can you please show me how it works by adding a bit of code to mine?
I will be very grateful if you did that, then i will understand.
Regards

11

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