Touch get wrong values more you go away from display center

[gmgunderground]

M5.Touch get wrong X and Y values more you go away from display center. The same problem there is with M5Core2. How to fix it? With this type of issue the display touch is compliteli useless. X and Y are not centered with the touch point.

https://user-images.githubusercontent.com/3244031/173841585-67615997-15f1-4aa2-a36c-80b45756c9c1.mp4

[lovyan03]

Hello @gmgunderground .

Do you mean that you shift slightly toward the center of the screen from the touched position?

If so, the following code will allow some adjustment.

#include <M5Unified.h>

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

  uint16_t data[8];

/// Calibrate by touching the four corners of the screen in sequence.
  M5.Display.calibrateTouch(data, TFT_WHITE, TFT_BLACK, 32);

/// The data array contains the coordinate values of the four corners.
  Serial.print("calibrate data:\n");
  for (int i = 0 ; i < 8; ++i)
  {
    Serial.printf("[%d] = %d\n", i, data[i]);
  }

/// Or, directly specify the coordinate values of the four corners without touching the screen.
/// If the value is set a little closer to the center, the touch coordinates will be a little outward.
/*
  data[0] =   8;   // left top X
  data[1] =   8;   // left top Y
  data[2] =   8;   // left bottom X
  data[3] = 223;   // left bottom Y
  data[4] = 303;   // right top X
  data[5] =   8;   // right top Y
  data[6] = 303;   // right bottom X
  data[7] = 223;   // right bottom Y
*/

/// set calibrate data:
  M5.Display.setTouchCalibrate(data);
}

void loop(void)
{
  m5gfx::touch_point_t tp[5];
  auto tc = M5.Display.getTouch(tp, 5);
  if (tc)
  {
    M5.Display.fillScreen(0);
    for (int i = 0; i < tc; ++i)
    {
      M5.Display.drawCircle(tp[i].x, tp[i].y, 64, rand());
      M5.Display.drawFastHLine(0, tp[i].y, M5.Display.width(), rand());
      M5.Display.drawFastVLine(tp[i].x, 0, M5.Display.height(), rand());
    }
  }
}

[gmgunderground]

@lovyan03 Thanks for the code, it actually helps a bit to improve the touch behavior, but it still remains quite inaccurate. Especially in the corners, the measured values of X and Y are quite wrong, significantly improving towards the center of the screen

[lovyan03]

@gmgunderground Have you tried adjusting data? If it always shifts toward the center, I think you can compensate by changing the calibration value closer to the center. For example, try the following .

  uint16_t data[8];

  data[0] =  32;   // left top X
  data[1] =  32;   // left top Y
  data[2] =  32;   // left bottom X
  data[3] = 207;   // left bottom Y
  data[4] = 287;   // right top X
  data[5] =  32;   // right top Y
  data[6] = 287;   // right bottom X
  data[7] = 207;   // right bottom Y

  M5.Display.setTouchCalibrate(data);

---

BTW, there is an update to the Core2 touch panel firmware. This reduces the problem of coordinates being shifted vertically at the top of the screen. ( It may have already been updated if your purchase was recent. )

Try to write Core2_Tools once using M5Burner. If the touch panel firmware is out of date, Core2_Tools will perform the update at startup.

Once the firmware update is performed, it will remain effective even if other programs are written thereafter.

[gmgunderground]

@gmgunderground Have you tried adjusting data? If it always shifts toward the center, I think you can compensate by changing the calibration value closer to the center. For example, try the following .

  uint16_t data[8];

  data[0] =  32;   // left top X
  data[1] =  32;   // left top Y
  data[2] =  32;   // left bottom X
  data[3] = 207;   // left bottom Y
  data[4] = 287;   // right top X
  data[5] =  32;   // right top Y
  data[6] = 287;   // right bottom X
  data[7] = 207;   // right bottom Y

  M5.Display.setTouchCalibrate(data);

BTW, there is an update to the Core2 touch panel firmware. This reduces the problem of coordinates being shifted vertically at the top of the screen. ( It may have already been updated if your purchase was recent. )

Try to write Core2_Tools once using M5Burner. If the touch panel firmware is out of date, Core2_Tools will perform the update at startup.

Once the firmware update is performed, it will remain effective even if other programs are written thereafter.

I installed M5 Tools and it updated the display firmware at startup. Now the touch screen seems to be doing much better. Thank you

[lovyan03]

@gmgunderground Congratulations on the improvement of the touch panel performance issue !

Am I correct in assuming that this Issue has been resolved?

[gmgunderground]

Now all it's ok