Core2 and M5Unified display no longer works

[HappyUser]

Wow,
I have uploaded the standard M5Unified Button code to my M5Core2.
I know the program is running because my serial.print shows button counts.
But the display shows nothing.
I have tried this on multiple Core2 of which I know the display is not defect. All boards and libs are updated (as fwr as i know).
What am i doing wrong here?
Thanks

#include <M5Unified.h>

void setup(void)
{
  M5.begin();

  Serial.begin(115200);

  /// For models with EPD : refresh control
  M5.Display.setEpdMode(epd_mode_t::epd_fastest); // fastest but very-low quality.

  if (M5.Display.width() < M5.Display.height())
  { /// Landscape mode.
    M5.Display.setRotation(M5.Display.getRotation() ^ 1);
  }
}

void loop(void)
{
  M5.delay(1);

  M5.update();
//------------------- Button test
/*
/// List of available buttons:
  M5Stack BASIC/GRAY/GO/FIRE:  BtnA,BtnB,BtnC
  M5Stack Core2:               BtnA,BtnB,BtnC,BtnPWR
  M5Stick C/CPlus:             BtnA,BtnB,     BtnPWR
  M5Stick CoreInk:             BtnA,BtnB,BtnC,BtnPWR,BtnEXT
  M5Paper:                     BtnA,BtnB,BtnC
  M5Station:                   BtnA,BtnB,BtnC,BtnPWR
  M5Tough:                                    BtnPWR
  M5Atom M5AtomU:              BtnA
  M5Stamp Pico/C3/C3U:         BtnA
*/

  static constexpr const int colors[] = { TFT_WHITE, TFT_CYAN, TFT_RED, TFT_YELLOW, TFT_BLUE, TFT_GREEN };
  static constexpr const char* const names[] = { "none", "wasHold", "wasClicked", "wasPressed", "wasReleased", "wasDeciedCount" };

  int w = M5.Display.width() / 5;
  int h = M5.Display.height();
  M5.Display.startWrite();

  /// BtnPWR: "wasClicked"/"wasHold"  can be use.
  /// BtnPWR of CoreInk: "isPressed"/"wasPressed"/"isReleased"/"wasReleased"/"wasClicked"/"wasHold"/"isHolding"  can be use.
  int state = M5.BtnPWR.wasHold() ? 1
            : M5.BtnPWR.wasClicked() ? 2
            : M5.BtnPWR.wasPressed() ? 3
            : M5.BtnPWR.wasReleased() ? 4
            : M5.BtnPWR.wasDecideClickCount() ? 5
            : 0;

  if (state)
  {
    M5_LOGI("BtnPWR:%s  count:%d", names[state], M5.BtnPWR.getClickCount());
    M5.Display.fillRect(w*0, 0, w-1, h, colors[state]);
    
  }

  /// BtnA,BtnB,BtnC,BtnEXT: "isPressed"/"wasPressed"/"isReleased"/"wasReleased"/"wasClicked"/"wasHold"/"isHolding"  can be use.
  state = M5.BtnA.wasHold() ? 1
        : M5.BtnA.wasClicked() ? 2
        : M5.BtnA.wasPressed() ? 3
        : M5.BtnA.wasReleased() ? 4
        : M5.BtnA.wasDecideClickCount() ? 5
        : 0;
  if (state)
  {
    M5_LOGI("BtnA:%s  count:%d", names[state], M5.BtnA.getClickCount());
    M5.Display.fillRect(w*1, 0, w-1, h, colors[state]);
    Serial.println(M5.BtnA.getClickCount());
  }

  state = M5.BtnB.wasHold() ? 1
        : M5.BtnB.wasClicked() ? 2
        : M5.BtnB.wasPressed() ? 3
        : M5.BtnB.wasReleased() ? 4
        : M5.BtnB.wasDecideClickCount() ? 5
        : 0;
  if (state)
  {
    M5_LOGI("BtnB:%s  count:%d", names[state], M5.BtnB.getClickCount());
    M5.Display.fillRect(w*2, 0, w-1, h, colors[state]);
  }

  state = M5.BtnC.wasHold() ? 1
        : M5.BtnC.wasClicked() ? 2
        : M5.BtnC.wasPressed() ? 3
        : M5.BtnC.wasReleased() ? 4
        : M5.BtnC.wasDecideClickCount() ? 5
        : 0;
  if (state)
  {
    M5_LOGI("BtnC:%s  count:%d", names[state], M5.BtnC.getClickCount());
    M5.Display.fillRect(w*3, 0, w-1, h, colors[state]);
  }

  state = M5.BtnEXT.wasHold() ? 1
        : M5.BtnEXT.wasClicked() ? 2
        : M5.BtnEXT.wasPressed() ? 3
        : M5.BtnEXT.wasReleased() ? 4
        : M5.BtnEXT.wasDecideClickCount() ? 5
        : 0;
  if (state)
  {
    M5_LOGI("BtnEXT:%s  count:%d", names[state], M5.BtnEXT.getClickCount());
    M5.Display.fillRect(w*4, 0, w-1, h, colors[state]);
  }
  M5.Display.endWrite();
}

#if !defined ( ARDUINO ) && defined ( ESP_PLATFORM )
extern "C" {
  void loopTask(void*)
  {
    setup();
    for (;;) {
      loop();
    }
    vTaskDelete(NULL);
  }

  void app_main()
  {
    xTaskCreatePinnedToCore(loopTask, "loopTask", 8192, NULL, 1, NULL, 1);
  }
}
#endif

[henryCharm]

The problem is caused by a line in your code that sets the display to "EPD mode," which is only for e-paper (e-ink) displays. The M5Core2 uses an LCD screen, not an e-paper screen.

This line:

M5.Display.setEpdMode(epd_mode_t::epd_fastest);

is not compatible with the M5Core2 screen.

To fix the issue:

Remove or comment out that line from your code.

After doing this, the display should start working normal

[felmue]

Hello @HappyUser

hmm, the button sample code works fine as it is for me. Tested with M5Core2 and M5Core2 v1.1.

For reference: I was using Arduino library v3.2.1, M5Unfied v0.2.8 and M5GFX v0.2.13.

@henryCharm : you are correct, the line M5.Display.setEpdMode(epd_mode_t::epd_fastest); is only used / required for ePaper however it is simply ignored on non ePaper displays. So yes, it would be cleaner to remove the line, but I don't think it does any harm. I think the reason it is there is so that the example works on different M5Cores.

Thanks
Felix

[HappyUser]

@felmue said in Core2 and M5Unified display no longer works:

Arduino library v3.2.1,

Dear all.

Thanks
@Felix : what do you exactly mean with Arduino library v3.2.1,?
My settings:
Arduino IDE 2.3.6
M5GFX : 0.2.13
M5Unified 0.2.8
Arduino ESP32 Boards 2.0.18

M5Core2 display stays black. I have tried the same software on an M5Stick. Display also stays Black,
Software is running. Serial.print also shows the correct display dimensions.
Tried the software on a M5CoreS3 and the display is responding!!
Tried the software in M5Core2 AWS link text. and the display is responding!

So apparantly for the M5Core2 and M5Stick I am missing something. M5CoreS3 works like expected?
Anyone a clue?
I am really grateful.

(*As i noticed that the height and widt of the screen are correcty read and the buttons appear to be working, could it be that the backlight is just off?. Mind you, i have ttried on several devices so it is not a failure of one device *)

[HappyUser]

@HappyUser
Further research
Tried the default M5GFX Bargraph example (attached)
No display on M5Stick and M5COre2
Works perfect on M5StickCPlus and M5CoreS3

This is realy weird.
I hope someone can help

#include <arduino.h>
#include <M5GFX.h>
M5GFX display;

//#include <M5UnitOLED.h>
//M5UnitOLED display; // default setting
//M5UnitOLED display ( 21, 22, 400000 ); // SDA, SCL, FREQ

//#include <M5UnitLCD.h>
//M5UnitLCD display;  // default setting
//M5UnitLCD display  ( 21, 22, 400000 ); // SDA, SCL, FREQ

//#include <M5UnitGLASS2.h>
//M5UnitGLASS2 display;  // default setting
//M5UnitGLASS2 display ( 21, 22, 400000 ); // SDA, SCL, FREQ

// #include <M5AtomDisplay.h>
// M5AtomDisplay display;

static constexpr size_t BAR_COUNT = 64;
static int max_y[BAR_COUNT];
static int prev_y[BAR_COUNT];
static uint32_t colors[BAR_COUNT];

void setup(void)
{
  display.init();
  display.startWrite();
  display.fillScreen(TFT_BLACK);

  if (display.isEPD())
  {
    display.setEpdMode(epd_mode_t::epd_fastest);
  }
  if (display.width() < display.height())
  {
    display.setRotation(display.getRotation() ^ 1);
  }

  for (int x = 0; x < BAR_COUNT; ++x)
  {
    prev_y[x] = display.height();
    max_y[x] = display.height();
    int r=0,g=0,b=0;
    switch (x >> 4)
    {
    case 0:
      b = 255;
      g = x*0x11;
      break;
    case 1:
      b = 255 - (x&15)*0x11;
      g = 255;
      break;
    case 2:
      g = 255;
      r = (x&15)*0x11;
      break;
    case 3:
      r = 255;
      g = 255 - (x&15)*0x11;
      break;
    }
    colors[x] = display.color888(r,g,b);
  }
}

void loop(void)
{
  int h = display.height();

  static int i;
  ++i;
  display.waitDisplay();
  for (int x = 0; x < BAR_COUNT; ++x)
  {
    int y = (h>>1) - (sinf((float)((x-24)*i) / 3210.0f) + sinf((float)((x-40)*i) / 1234.0f)) * (h>>2);

    int xpos = x * display.width() / BAR_COUNT;
    int w = ((x+1) * display.width() / BAR_COUNT) - xpos - 1;
    if (max_y[x]+1 >= y) { max_y[x] = y-1; }
    else
    {
      if ((i & 3) ==0 )
      {
        display.fillRect(xpos, max_y[x]-3, w, 1, TFT_BLACK);
        max_y[x]++;
      }
    }
    display.fillRect(xpos, max_y[x]-3, w, 3, TFT_WHITE);
    if (prev_y[x] < y)
    {
      display.fillRect(xpos, prev_y[x], w, y - prev_y[x], TFT_BLACK);
    }
    else
    {
      display.fillRect(xpos, y, w, prev_y[x] - y, colors[x]);
    }
    prev_y[x] = y;
  }
  display.display();
}

[felmue]

Hello @HappyUser

I mean this arduino library.

Maybe this article helps.

Note: I am using Visual Code (and not Arduino IDE).

Thanks
Felix