TFT display resets after any instruction sent to it

[kosainabro]

Hello, I am a bit confused with the state of my display right now.
It's a touchscreen shield that works with the mcufriend library, it has a screen resolution of 320x480. So the problem is, everytime I go into a loop to check if the screen is being touched in a certain range of coordinates (any range of coordinates given to it), it works fine. But the moment I send a tft.print() in the if statement, it just goes blank until a tft.reset() is executed. The touch is still responsive when the screen goes blank.

Any help will be appreciated a LOT

Here's ALL of my code:

// the regular Adafruit "TouchScreen.h" library only works on AVRs

// different mcufriend shields have Touchscreen on different pins
// and rotation.
// Run the TouchScreen_Calibr_native sketch for calibration of your shield

#include <MCUFRIEND_kbv.h>
MCUFRIEND_kbv tft;       // hard-wired for UNO shields anyway.
#include <TouchScreen.h>

char *name = "Fcalc shield";  //edit name of shield
/*
const int XP=6,XM=A2,YP=A1,YM=7; //ID=0x9341
const int TS_LEFT=907,TS_RT=136,TS_TOP=942,TS_BOT=139;
*/

const int XP=8,XM=A2,YP=A3,YM=9; //320x480 ID=0x9486
const int TS_LEFT=123,TS_RT=909,TS_TOP=956,TS_BOT=95;

TouchScreen ts = TouchScreen(XP, YP, XM, YM, 300);
TSPoint tp;

// Object with String keys and String values
typedef struct _tuple { const char key; int val; } Tuple;
// ntouch means number keypad touch button coordinates

#define MINPRESSURE 200
#define MAXPRESSURE 1000

uint8_t Orientation = 0;    //PORTRAIT
uint16_t ID;

// Assign human-readable names to some common 16-bit color values:
#define BLACK   0x0000
#define BLUE    0x001F
#define RED     0xF800
#define GREEN   0x07E0
#define CYAN    0x07FF
#define MAGENTA 0xF81F
#define YELLOW  0xFFE0
#define WHITE   0xFFFF
#define GRAY    0x7BEF

#define topBarColor 0xCE79
#define topTextColor BLACK
#define topLineColor 0x0000

void show_Serial(void)
{
    Serial.println(F("Most Touch Screens use pins 6, 7, A1, A2"));
    Serial.println(F("But they can be in ANY order"));
    Serial.println(F("e.g. right to left or bottom to top"));
    Serial.println(F("or wrong direction"));
    Serial.println(F("Edit name and calibration statements\n"));
    Serial.println(name);
    Serial.print(F("ID=0x"));
    Serial.println(ID, HEX);
    Serial.println("Screen is " + String(tft.width()) + "x" + String(tft.height()));
    Serial.println("Calibration is: ");
    Serial.println("LEFT = " + String(TS_LEFT) + " RT  = " + String(TS_RT));
    Serial.println("TOP  = " + String(TS_TOP)  + " BOT = " + String(TS_BOT));
    Serial.println("Wiring is always PORTRAIT");
    Serial.println("YP=" + String(YP)  + " XM=" + String(XM));
    Serial.println("YM=" + String(YM)  + " XP=" + String(XP));
}

void show_tft(void)
{
    String msg = "";
    tft.fillScreen(WHITE);
    tft.setTextColor(BLACK);
    tft.setCursor(0, 0);
    tft.setTextSize(1);
    tft.print(F("ID=0x"));
    tft.println(ID, HEX);
    tft.println("Current panel: " + String(tft.width()) + "x" + String(tft.height()));
    tft.println("");
    tft.setTextColor(BLUE);
    tft.setTextSize(2);
    tft.println("Formula Calculator v0.1");
    tft.println("Designed by Kosain");
    tft.setTextColor(BLACK);
    tft.setTextSize(1);
    tft.println("");
    tft.println("PORTRAIT Values:");
    tft.println("LEFT = " + String(TS_LEFT) + " RT  = " + String(TS_RT));
    tft.println("TOP  = " + String(TS_TOP)  + " BOT = " + String(TS_BOT));
    tft.println("\nWiring is: ");
    tft.println("YP=" + String(YP)  + " XM=" + String(XM));
    tft.println("YM=" + String(YM)  + " XP=" + String(XP));
    tft.setTextSize(2);
    tft.setTextColor(0x0320);
    tft.setCursor((tft.width() - 65) / 2, (tft.height() * 2) / 4);
    tft.print("Run >_");
    tft.setCursor(0, 0);
    tft.drawRect(110, 220, 105, 55, 0x0320);
    tft.setTextColor(BLACK, WHITE);
    tft.setCursor(0, (tft.height() * 6) / 8);
    tft.println("Touch screen for");
    tft.print("pos and depth");
    while (1) {
        tp = ts.getPoint();
        tft.setTextColor(BLACK, WHITE);
        pinMode(XM, OUTPUT);
        pinMode(YP, OUTPUT);
        if (tp.z < MINPRESSURE || tp.z > MAXPRESSURE) continue;
        if (tp.x > 402 && tp.x < 645  && tp.y > 480 && tp.y < 565) break;
        tft.setCursor(0, (tft.height() * 3) / 4);
        tft.println("tp.x=" + String(tp.x) + " tp.y=" + String(tp.y));
        if (tp.z < 540) {
          tft.setTextColor(MAGENTA, WHITE);
          msg = "Push lightly                 ";
        }
        if (tp.z < 500) {
          tft.setTextColor(RED, WHITE);
          msg = "Don't push too hard!!        ";
        }
        if (tp.z < 400) {
          tft.setTextColor(RED, WHITE);
          msg = "Don't use fingers!           ";
        }
        if (tp.z < 300) {
          tft.setTextColor(RED, WHITE);
          msg = "Multitouch isn't supported...";
        }
        if (tp.z > 540) {
          tft.setTextColor(BLACK, WHITE);
          msg = "                             ";
        }
        tft.println("tp.z=" + String(tp.z) + "       ");
        tft.println(msg);

        
    }
}


void setup(void)
{
    
    uint16_t tmp;

    tft.reset();
    ID = tft.readID();
    tft.begin(ID);
    Serial.begin(9600);
    show_Serial();
    tft.setRotation(Orientation);
    tft.fillScreen(BLACK);
    
    show_tft();

    // BOXSIZE = tft.width() / 6;

    tft.fillScreen(BLACK);
    tft.fillRect(0, 0, tft.width(), 30, BLACK);
    tft.drawLine(0, 30, tft.width(), 30, WHITE);
}

uint16_t xpos, ypos;  //screen coordinates


void touchPos(){
  // uint16_t xpos, ypos;  //screen coordinates
  tp = ts.getPoint();   //tp.x, tp.y are ADC values
  switch (Orientation) {
  case 0:
    xpos = map(tp.x, TS_LEFT, TS_RT, 0, tft.width());
    ypos = map(tp.y, TS_TOP, TS_BOT, 0, tft.height());
    break;
  case 1:
    xpos = map(tp.y, TS_TOP, TS_BOT, 0, tft.width());
    ypos = map(tp.x, TS_RT, TS_LEFT, 0, tft.height());
    break;
  case 2:
    xpos = map(tp.x, TS_RT, TS_LEFT, 0, tft.width());
    ypos = map(tp.y, TS_BOT, TS_TOP, 0, tft.height());
    break;
  case 3:
    xpos = map(tp.y, TS_BOT, TS_TOP, 0, tft.width());
    ypos = map(tp.x, TS_LEFT, TS_RT, 0, tft.height());
    break;
  }
}

void screenBtn(String type){
  if (type == "back"){
    tft.setCursor(283, 47);
    tft.fillRect(280, 40, 30, 30, 0x2800);
    tft.drawRect(279, 39, 31, 31, RED);
    tft.drawRect(280, 40, 30, 31, RED);
    tft.setTextColor(WHITE);
    tft.print("<-");
  }
  if (type == "close"){
    tft.setCursor(290, 47);
    tft.fillRect(280, 40, 30, 30, 0x2800);
    tft.drawRect(279, 39, 31, 31, RED);
    tft.drawRect(280, 40, 30, 31, RED);
    tft.setTextColor(WHITE);
    tft.print("X");
  }
}

int x1, x2, y1, y2;

bool screenBtnTouch(String type, bool debugPrintValues){
  tp = ts.getPoint();
  
  if (type == "back")
  {
    // int x1, x2, y1, y2;
    x1 = 820;
    x2 = 870;
    y1 = 838;
    y2 = 888;
  }
  
  if (debugPrintValues == true)
  {
    Serial.println(String(tp.x) + " " + String(tp.y));
    Serial.println("pressure: " + String(tp.z));
  }
  return (tp.x > x1 && tp.x < x2 && tp.y > y1 && tp.y < y2);
}

void loadScreen(String scr, bool resetTft){
  if (resetTft)
  {
    tft.begin(ID);
    tft.fillScreen(WHITE);
  }
  
  tft.fillRect(0, 0, tft.width(), 30, topBarColor);
  tft.drawLine(0, 30, tft.width(), 30, topLineColor);

  tft.setTextSize(2);
  tft.setCursor(5, 5);

  tft.setTextColor(topTextColor);
  tft.print("Waiting for GUI Refresh...");
  // tft.fillRect(0, 31, tft.width(), tft.height(), 0xF7BE);
  tft.fillRect(0, 31, tft.width(), tft.height(), WHITE);
  
  tft.setCursor(5, 5);
  
  if (scr == "home")
  {
    tft.setCursor(5, 5);
    tft.setTextColor(topTextColor);

    tft.fillRect(0, 0, tft.width(), 30, topBarColor);
    tft.print("Fcalc v0.1");
    
    tft.setCursor(0, 0);
    tft.setTextSize(3);
    tft.setTextColor(BLACK);

    tft.setCursor(15, 50);
    tft.println("Formulas:");
    tft.setTextSize(2);

    int homeBtnY = 102;
    int homeBtnXlen = 215;
    
    tft.setCursor(22, homeBtnY);
    tft.fillRect(15, homeBtnY - 8, homeBtnXlen, 30, BLACK);
    tft.setCursor(28, homeBtnY - 5);
    tft.fillRect(20, homeBtnY - 12, homeBtnXlen, 30, 0x075F);
    tft.print("Quadratic (Poly2)");

    homeBtnY += 50;
    tft.setCursor(22, homeBtnY);
    tft.fillRect(15, homeBtnY - 8, homeBtnXlen, 30, BLACK);
    tft.setCursor(28, homeBtnY - 5);
    tft.fillRect(20, homeBtnY - 12, homeBtnXlen, 30, 0x07F0);
    tft.print("Term (Tn/Un)");

    homeBtnY += 50;
    tft.setCursor(22, homeBtnY);
    tft.fillRect(15, homeBtnY - 8, homeBtnXlen, 30, BLACK);
    tft.setCursor(28, homeBtnY - 5);
    tft.fillRect(20, homeBtnY - 12, homeBtnXlen, 30, 0x2FE0);
    tft.print("Sum of n (Sn)");
  }
  if (scr == "formulaQuad")
  {
    tft.setTextColor(BLACK);

    tft.fillRect(0, 0, tft.width(), 30, topBarColor);
    tft.setTextColor(topTextColor);
    tft.print("Fcalc v0.1");
    tft.setTextColor(0x03B0);
    tft.print(" -> Quadratic");

    tft.setCursor(0, 0);
    tft.setTextColor(BLACK);

    tft.setTextSize(3);
    tft.setCursor(15, 50);
    tft.println("Quadratic");
    tft.setTextSize(2);
    tft.setCursor(15, 75);
    tft.println("ax^2 + bx + c = 0");

    int homeBtnY = 120;
    int homeBtnXlen = 40;

    int yTBoxA, yTBoxB, yTBoxC;
    
    tft.setCursor(22, homeBtnY);
    tft.fillRect(15, homeBtnY - 8, homeBtnXlen, 30, BLACK);
    tft.setCursor(28, homeBtnY - 5);
    tft.fillRect(20, homeBtnY - 12, homeBtnXlen, 30, 0xFCB2);
    tft.print("a=");
    tft.setCursor(80, homeBtnY - 5);
    yTBoxA = homeBtnY - 5;
    tft.print("?");

    homeBtnY += 50;
    tft.setCursor(22, homeBtnY);
    tft.fillRect(15, homeBtnY - 8, homeBtnXlen, 30, BLACK);
    tft.setCursor(28, homeBtnY - 5);
    tft.fillRect(20, homeBtnY - 12, homeBtnXlen, 30, 0x97F2);
    tft.print("b=");
    yTBoxB = homeBtnY - 5;
    tft.setCursor(80, homeBtnY - 5);
    tft.print("?");

    homeBtnY += 50;
    tft.setCursor(22, homeBtnY);
    tft.fillRect(15, homeBtnY - 8, homeBtnXlen, 30, BLACK);
    tft.setCursor(28, homeBtnY - 5);
    tft.fillRect(20, homeBtnY - 12, homeBtnXlen, 30, 0x94BF);
    tft.print("c=");
    yTBoxC = homeBtnY - 5;
    tft.setCursor(80, homeBtnY - 5);
    tft.print("?");

    screenBtn("back");
  }
  if (scr == "formulaAPTerm")
  {
    tft.setTextColor(BLACK);

    tft.fillRect(0, 0, tft.width(), 30, topBarColor);
    tft.setTextColor(topTextColor);
    tft.print("Fcalc v0.1");
    tft.setTextColor(0x0408);
    tft.print(" -> AP Tn");

    tft.setCursor(0, 0);
    tft.setTextColor(BLACK);

    tft.setTextSize(3);
    tft.setCursor(15, 50);
    tft.println("Term Number");
    tft.setTextSize(2);
    tft.setCursor(15, 75);
    tft.println("Tn = a + (n-1)d");

    int homeBtnY = 120;
    int homeBtnXlen = 40;

    int yTBoxA, yTBoxB, yTBoxC;
    
    tft.setCursor(22, homeBtnY);
    tft.fillRect(15, homeBtnY - 8, homeBtnXlen, 30, BLACK);
    tft.setCursor(28, homeBtnY - 5);
    tft.fillRect(20, homeBtnY - 12, homeBtnXlen, 30, 0xFB2C);
    tft.print("a=");
    tft.setCursor(80, homeBtnY - 5);
    yTBoxA = homeBtnY - 5;
    tft.print("?");

    homeBtnY += 50;
    tft.setCursor(22, homeBtnY);
    tft.fillRect(15, homeBtnY - 8, homeBtnXlen, 30, BLACK);
    tft.setCursor(28, homeBtnY - 5);
    tft.fillRect(20, homeBtnY - 12, homeBtnXlen, 30, 0xFFEC);
    tft.print("d=");
    yTBoxB = homeBtnY - 5;
    tft.setCursor(80, homeBtnY - 5);
    tft.print("?");

    homeBtnY += 50;
    tft.setCursor(22, homeBtnY);
    tft.fillRect(15, homeBtnY - 8, homeBtnXlen, 30, BLACK);
    tft.setCursor(28, homeBtnY - 5);
    tft.fillRect(20, homeBtnY - 12, homeBtnXlen, 30, 0x94BF);
    tft.print("n=");
    yTBoxC = homeBtnY - 5;
    tft.setCursor(80, homeBtnY - 5);
    tft.print("?");

    screenBtn("back");
  }
}

int screenKeypad(bool show, String title)
{
  // action: bring up keypad
  int colorBg, colorTopLine, colorText, colorTitle;
  colorBg = 0xE73C;
  colorTopLine = BLACK;
  colorText = BLACK;
  colorTitle = BLUE;

  if (show == true)
  {
    tft.fillRect(0, 300, tft.width(), tft.height() - 300, colorBg);
    tft.drawLine(0, 300, tft.width(), 300, colorTopLine);
    tft.setCursor(5, 326);
    tft.setTextColor(colorText);
    tft.println(title);
    tft.drawRect(5, 305, tft.width() - 10, 17, BLACK);
    tft.fillRect(6, 306, tft.width() - 12, 15, WHITE);

    tft.fillRect(tft.width() - 20 - 5, tft.height() - 20 - 5, 20, 20, RED); // make keypad close button

    // keypad buttons:
    tft.setTextSize(2);
    tft.drawRect(9, 351, 30, 30, BLACK);
    tft.fillRect(10, 350, 30, 30, WHITE);
    tft.setCursor(18, 355);
    tft.print("1");

    // ntouch means numerical keypad button touch coordinates. Coordinates stored in dictionary
    // touch colliders set in a list:

    /*
    dict ntouch[] = {
      {"onex1", 153},
      {"onex2", 217},
      {"oney1", 276},
      {"oney2", 322}
    };
    */

    int onex1, onex2, oney1, oney2;
    onex1 = 153;
    onex2 = 217;
    oney1 = 276;
    oney2 = 322;

    /*
    ntouch["onex1"] = 153;
    ntouch["onex2"] = 217;
    ntouch["oney1"] = 276;
    ntouch["oney2"] = 322;
    */

    while(1)
    {
      tp = ts.getPoint();
      tft.setCursor(8, 308);
      if (tp.z < MINPRESSURE || tp.z > MAXPRESSURE) continue;
      Serial.println(String(tp.x) + " " + String(tp.y));
      
      /*
      x1 = ntouch["onex1"];
      x2 = ntouch["onex2"];
      y1 = ntouch["oney1"];
      y2 = ntouch["oney2"];
      */

      x1 = 857;
      x2 = 885;
      y1 = 113;
      y2 = 137;
      if (tp.x > x1 && tp.x < x2  && tp.y > y1 && tp.y < y2)
      {
        loadScreen("formulaQuad", true);
        Serial.println("Closed");
        break;
        return NULL;
      }

      // keypad button touch logic:

      if (tp.x > onex1 && tp.x < onex2 && tp.y > oney1 && tp.y < oney2)
      {
        tft.setTextSize(1);
        tft.print("1");
        Serial.println("One pressed");

        while(tp.z > 10) //{tp = ts.getPoint();} // wait until user lets go of button
        {
          tp = ts.getPoint();
          tft.print("hi"); // <- Over here
          // the printing of hi is a test here, it goes blank the moment it executes it
        }

        Serial.println("One released");
        
      }

      
    }
    
  }
  if (show == false)
  {
    tft.fillRect(0, 300, tft.width(), tft.height() - 300, WHITE);
  }
  
}

void loop()
{   
    // if sharing pins, you'll need to fix the directions of the touchscreen pins
    pinMode(XM, OUTPUT);
    pinMode(YP, OUTPUT);
    // we have some minimum pressure we consider 'valid'
    // pressure of 0 means no pressing!
    
    
    int x1, x2, y1, y2;
    String screen;
    
    while(1)
    {
      loadScreen("home", true); // formula selection screen
      tp = ts.getPoint();
      String formulaButtonList[] =
      {
        "formulaQuad",
        "formulaAPTerm",
        "formulaAPSum"
      };
      
      while (1) { // logic loop for selecting formula or next screen
        tp = ts.getPoint();
        tft.setTextColor(BLACK, WHITE);
        pinMode(XM, OUTPUT);
        pinMode(YP, OUTPUT);
        if (tp.z < MINPRESSURE || tp.z > MAXPRESSURE) continue;
        // Serial.println(String(tp.x) + " " + String(tp.y));
        if (tp.x > 183 && tp.x < 694  && tp.y > 750 && tp.y < 794)
        {
          screen = formulaButtonList[0];
          break;
        }
        if (tp.x > 183 && tp.x < 694  && tp.y > 656 && tp.y < 705)
        {
          screen = formulaButtonList[1];
          break;
        }
        if (tp.x > 183 && tp.x < 694  && tp.y > 576 && tp.y < 619)
        {
          screen = formulaButtonList[2];
          //break;
        }
      }

      tft.setCursor(5, 5);
      tft.fillRect(0, 0, tft.width(), 30, topBarColor);

      // load corresponding screen:
      loadScreen(screen, false);

      tft.setTextColor(BLACK);
      tft.setTextSize(2);
      
      while(1) // logic for handling the interactivity of the screen:
      {
        // back button logic:
        tp = ts.getPoint();
        pinMode(XM, OUTPUT);
        pinMode(YP, OUTPUT);
        if (tp.z < MINPRESSURE || tp.z > MAXPRESSURE)
        {
          if (screenBtnTouch("back", false) == true)
          {
            screen = "home";
            break;
          }
        }

        if (tp.z < MINPRESSURE || tp.z > MAXPRESSURE) continue;
        // quadratic formula interactivity:
        if (screen == "formulaQuad")
        {
          tft.setTextColor(BLACK);
          tft.setTextSize(2);
          
          int a, b, c;
          
          x1 = 186;
          x2 = 258;
          y1 = 720;
          y2 = 764;

          if (tp.x > x1 && tp.x < x2  && tp.y > y1 && tp.y < y2)
          {
            int a = screenKeypad(true, "Enter value for (a).");
            
            tft.setTextColor(BLACK);
            tft.setTextSize(2);
          }
        }
      }
    }
}

Thanks in advance.

[mancera1979]

Have you identified the offending tft.print?

Also, have you tried breaking up

@kosainabro

tft.println("tp.x=" + String(tp.x) + " tp.y=" + String(tp.y));

in 4 separate instructions to avoid using “String" function?

[xfpd]

@kosainabro

while(1)

Are you getting stuck in one of the five while(1) loops?

[cedarlakeinstruments]

I ran this code with an mcufriend TFT display and it worked fine. Only difference is that my screen is 240x320.

[kosainabro]

See, the strange part is that this line of code does not do this issue.

[kosainabro]

I'm pretty sure it isn't stuck because the output from the serial monitor proves that it does get out.