Calibration issue (and ghost rawZ numbers) - TFT touchscreen ST7789

[ArthurFR1]

Hello!

I got a 2.8' TFT touchscreen (driver : ST7789). The screen works perfectly with the library and I've got no issue displaying text and examples such as TFT_Starfield.

However, I'm facing some issues while trying to test the touchscreen.
In fact, I am unable to get through the calibration test to get to the Keypad_240_320 example.

Tough the touch is indeed taken into account, because when I run Test_Touch_Controller, coordinates are printed in the monitor when I'm touching the screen (see the video, the X number provides zero when i'm not touching the screen, Y gives numbers between 3380 and 3320, and Z gives numbers between 2 and 26 even though I'm not touching the screen, i'm not sure it's a normal behavior).

Please see the uploaded video (30 sec) that sums up my issue.

video_2023-11-05_20-50-18.mp4

I'm using :

• Arduino IDE
• Generic TFT touchscreen (with generic XPT2046 chip for touch capabilities)
• TFT_eSPI version 2.5.31
• ESP32 devboard wired to the TFT screen
• TFT's driver : ST7789

What I've done & tried :

• Raising the touch threshold to 600
• Switching SPI clock rate to 10MHz and to 1MHz
• Playing around with code and setup with no actual results
• TOUCH_CS has been defined
• Right driver (ST7789), right user setup (18), right screen dimention (240x320) have all been set up correclty.
• Code uploads with no warnings nor issues

I've been through documentation & community issues for a while now and I think I'm missing something.
Does anyone have had the same issue?
Thanking you in advance for your response.
Regards

[Bodmer]

The sketch you are running requires a memory partition to be setup for SPIFFS so I suspect that has not been done.

The Test_Touch_Controller output looks good, you can expect some "noise" on the Z (pressure) reading.

To avoid the need for a SPIFFS partition, it would be better to use this example sketch to calibrate the touch controller.

[ArthurFR1]

Hi @Bodmer , thank you for your reply.

After few days of trying to partition 3MB of SPIFFS

or event trying the Touch_calibrate.ino example sketch, it seems that either the screen is crashing when i touch it multiple times (white screen), or either it simply doesn't work (Can't calibrate nor use the touch screen for buttons/keypad/etc.).

Even though I replace the touch initialization & calibration by : uint16_t calData[5] = { 300, 3800, 300, 3800, 6 }; tft.setTouch(calData);, it shows no results.