Hard time trying to calibrate ST7796S

[wolfrose]

Hi,

I've tried over and over to calibrate the ST7796S with TFTeSPI library. I don't know the calibration was easier with TFT_Touch by Rowboteer.

I tried this code:
Touch_calibrate.ino

With the same result.

And this is my touch.h settings:

           // Initialise with example calibration values so processor does not crash if setTouch() not called in setup()
		   // x0 298, x1 3609, y0 194, y1 3586
		   // old calibration x0 120, x1 3580, y0 280, y1 3900
  uint16_t touchCalibration_x0 = 298, touchCalibration_x1 = 3609, touchCalibration_y0 = 194, touchCalibration_y1 = 3586;
  uint8_t  touchCalibration_rotate = 0, touchCalibration_invert_x = 0, touchCalibration_invert_y = 1;

This is my simple button test:

#include <SPI.h>
#include <TFT_eSPI.h>

#define Z_THRSH 175

TFT_eSPI tft = TFT_eSPI();

struct button{
  uint16_t x;
  uint16_t y;
  uint16_t w;
  uint16_t h;
  uint16_t color;
};

button b1, b2, b3;

void setup(void) {
  Serial.begin(9600);
  Serial.println("\n\nStarting...");

  tft.init();
  
  tft.setRotation(0);
  
  tft.fillScreen(TFT_GREEN);
  initialize_button(b1, 30, 30, 50, 50, TFT_BLACK);
  initialize_button(b2, 30, 100, 50, 50, TFT_BLACK);
  initialize_button(b3, 30, 170, 50, 50, TFT_BLACK);
  draw_button(b1);
  draw_button(b2);
  draw_button(b3);
}

void loop() {
  read_button(b1);
  read_button(b2);
  read_button(b3);
}

These are the button functions:

unsigned long buttonTimer = millis();

void initialize_button(button &b, uint16_t button_x, uint16_t button_y, uint8_t button_w, uint8_t button_h, uint16_t button_color){
  b.x = button_x;
  b.y = button_y;
  b.w = button_w;
  b.h = button_h;
  b.color = button_color;
}

void draw_button(button &b){
  tft.fillRect(b.x, b.y, b.w, b.h, TFT_YELLOW);//b.color
}

void read_button(button &b){
  static bool toggle_button = 0;
  uint16_t x, y;
  uint16_t x_coordination, y_coordination;
  if(millis() - buttonTimer > 10){
    if(tft.getTouch(&x, &y, 350)){
      buttonTimer = millis();
      x_coordination = x;
      y_coordination = y;
      Serial.println("///////////////////////// read_button start");
      Serial.print("X = "); Serial.println(x_coordination);
      Serial.print("Y = "); Serial.println(y_coordination);
      Serial.println("========================= read_button end");
      Serial.println();
      if(x_coordination >= b.x && x_coordination <= b.x + b.w && y_coordination >= b.y && y_coordination <= b.y + b.h){
        if(!toggle_button){
          tft.fillRect(b.x, b.y, b.w, b.h, TFT_RED);//b.color
          toggle_button = 1;
        }
        else{
          tft.fillRect(b.x, b.y, b.w, b.h, TFT_BLUE);//b.color
          toggle_button = 0;
        }
      }
    }
  }
}

[wolfrose]

OK, I think I'm getting away with this setting for x & y touch calibration:

uint16_t touchCalibration_x0 = 120, touchCalibration_x1 = 3580, touchCalibration_y0 = 300, touchCalibration_y1 = 3650;

It was really a lot of trail and error process