Asking for help Again on E-paper Partial refresh

Other Hardware Displays
1

Hi all,
I am using the code below from https://www.instructables.com/E-Paper-Display-Partial-Refresh-With-Arduino/. Their code works really well.

They use a B/W 2.9" E-Paper display from Waveshare and an Arduino Nano.
I am using a B/W/R 2.9" E-Paper display from Waveshare and an ESP32
I have made some modifications for my color display, as seen in the code below.

In my case partial refresh is not working. The display does full refresh for every update.
I did raise a ticket with Waveshare asking for a dedicate driver for this display, but no answer from them.

I believe the problem in the driver.
Is there a more recent driver for this display?
Has anyone experienced same issue with this display?
I really appreciate any input.
Thank you very much.

#define ENABLE_GxEPD2_GFX 0
//#include <GxEPD2_BW.h>  // ORIGINAL CODE
#include <U8g2_for_Adafruit_GFX.h>

// --------------   My modifications -------------------
#include <GxEPD2_3C.h>  
//These work s but no partial refresh, only full refresh (copied from GxEPD2_display_selection.h)
GxEPD2_3C<GxEPD2_290c, GxEPD2_290c::HEIGHT> display(GxEPD2_290c(/*CS=5*/ SS, /*DC=*/ 17, /*RST=*/ 16, /*BUSY=*/ 4)); // GDEW029Z10
//GxEPD2_3C<GxEPD2_290_Z13c, GxEPD2_290_Z13c::HEIGHT> display(GxEPD2_290_Z13c(/*CS=5*/ SS, /*DC=*/ 17, /*RST=*/ 16, /*BUSY=*/ 4)); // GDEH029Z13
//This one not working at all
//GxEPD2_3C<GxEPD2_290_C90c, GxEPD2_290_C90c::HEIGHT> display(GxEPD2_290_C90c(/*CS=5*/ SS, /*DC=*/ 17, /*RST=*/ 16, /*BUSY=*/ 4)); // GDEM029C90
//-------------------------------------------------------- 

#if defined(__AVR)
#define MAX_DISPLAY_BUFFER_SIZE 800 
#define MAX_HEIGHT(EPD) (EPD::HEIGHT <= MAX_DISPLAY_BUFFER_SIZE / (EPD::WIDTH / 8) ? EPD::HEIGHT : MAX_DISPLAY_BUFFER_SIZE / (EPD::WIDTH / 8))
GxEPD2_BW<GxEPD2_290, MAX_HEIGHT(GxEPD2_290)> display(GxEPD2_290(/*CS=10*/ SS, /*DC=*/ 9, /*RST=*/ 8, /*BUSY=*/ 7));
#endif

U8G2_FOR_ADAFRUIT_GFX u8g2Fonts;

void setup()
{
  display.init();
  u8g2Fonts.begin(display); // connect u8g2 procedures to Adafruit GFX
  delay(1000);
}

void loop()
{
  display.fillScreen(GxEPD_WHITE);
  displayValues();
  delay(1000);  
}


void displayValues()
{
  
  float number; //A0 Value
  float number2; // A0 Value converted to voltage
  number = analogRead(A0);
  number2 = number/1023 * 5;
  

  display.setRotation(1); // 0--> No rotation ,  1--> rotate 90 deg
  uint16_t bg = GxEPD_WHITE;
  uint16_t fg = GxEPD_BLACK;
  u8g2Fonts.setFontMode(1);                 // use u8g2 transparent mode (this is default)
  u8g2Fonts.setFontDirection(0);            // left to right (this is default)
  u8g2Fonts.setForegroundColor(fg);         // apply Adafruit GFX color
  u8g2Fonts.setBackgroundColor(bg);         // apply Adafruit GFX color
  //u8g2Fonts.setFont(u8g2_font_helvR14_tf);  // select u8g2 font from here:  https://github.com/olikraus/u8g2/wiki/fntlistall

  u8g2Fonts.setFont(u8g2_font_logisoso32_tr); //u8g2_font_logisoso32_tn--->numbers only to save memory ; u8g2_font_logisoso32_tr , u8g2_font_logisoso32_tf -->numbers&letters
  
  uint16_t x = 150;
  uint16_t y = 50;
  display.setPartialWindow(0, 0, display.width(), 296); //this sets a window for the partial update, so the values can update without refreshing the entire screen.
  display.firstPage();
  do
  {
    display.fillScreen(bg);

    // Display A0 value
    u8g2Fonts.setCursor(90, y); 
    u8g2Fonts.print("A0:");
    u8g2Fonts.setCursor(x, y);
    u8g2Fonts.println(number,1);
  
   // Display Voltage of A0
   u8g2Fonts.setCursor(50, y +40);
    u8g2Fonts.print("Volts:");
   u8g2Fonts.setCursor(x, y + 40);
   u8g2Fonts.println(number2,1);
  }
  while (display.nextPage());
}
2

3-color e-paper displays can't do differential refresh (some can do b/w differential refresh, e.g. in a partial window: GxEPD2x_FastBlackWhiteOnColor.ino).

from GxEPD2_display_selection_new_style.h: (there you easily find the controller used)

//#define GxEPD2_DRIVER_CLASS GxEPD2_290c     // GDEW029Z10  128x296, UC8151 (IL0373)
//#define GxEPD2_DRIVER_CLASS GxEPD2_290_Z13c // GDEH029Z13  128x296, UC8151D

UltraChip e-paper controllers usually have partial-in and partial-out commands, means they can restrict refresh to a partial window. But the differential refresh is only possible for b/w.
SSD controllers have no partial-in and partial-out commands.

GxEPD2_290_Z13c.h:

    static const bool usePartialUpdateWindow = false; // needs be false, controller issue

You could set this to true, to see the issue.

3

Hi,
thank you for your replay.
I made the change but nothing changed.
Looks like I have to get B/W display. :unamused:

4

Not all B/W models support partial refresh. You should check with the maker.

5

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