Need help of TFT display

Other Hardware Displays
1

Hey guys

My project is to have a TDS(total dissolved matter) value on a TFT display.
I manage to spaguetti code my way till its time to display the values on screen,
on serial monitor it displays the correct(after verification)values on liquids, but i cant seem to point it to screen, doesnt matter where in screen, just that values being displayed correctly.

#include <Adafruit_GFX.h>    
#include <MCUFRIEND_kbv.h>
#include "TouchScreen.h"
#include <EEPROM.h>
#include "GravityTDS.h"

 
#define BLACK 0x0000
#define PURPLE 0x780F
#define BLUE 0x001F
#define GREEN 0x07E0
#define CYAN 0x07FF
#define RED 0xF800
#define MAGENTA 0xF81F
#define YELLOW 0xFFE0
#define WHITE 0xFFFF

 
#define TdsSensorPin A0
GravityTDS gravityTds;


#define YP A1 
#define XM A2  
#define YM 7   
#define XP 6  

#define MINPRESSURE 10
#define MAXPRESSURE 1000

TouchScreen ts = TouchScreen(XP, YP, XM, YM, 250);
TSPoint p;

MCUFRIEND_kbv tft;
float temperature = 25,tdsValue = 0;
uint16_t g_identifier;
uint8_t rotation=3;
uint32_t when = millis();
uint8_t size = 4;
uint8_t cor = 0;
uint32_t tdsSensorPin =0;

void setup()
{
    tft.begin(9600);
  tft.reset();
  Serial.begin(9600);

  g_identifier = tft.readID();  // get id 
  tft.begin(0x7793);            // to enable ST7793 driver code 

  tft.setRotation(rotation);    // sets text direction
  tft.fillScreen(BLACK);        // clear screen

    gravityTds.setPin(TdsSensorPin);
    gravityTds.setAref(3.3);  //reference voltage on ADC, default 5.0V on Arduino UNO
    gravityTds.setAdcRange(1024);  //1024 for 10bit ADC;4096 for 12bit ADC
    gravityTds.begin();  //initialization
   
}
 
void loop()
{
    
   

    //temperature = readTemperature();  //add your temperature sensor and read it
    gravityTds.setTemperature(temperature);  // set the temperature and execute temperature compensation
    gravityTds.update();  //sample and calculate
    tdsValue = gravityTds.getTdsValue();  // then get the value
    tft.setTextColor(WHITE,BLACK);
    tft.print(tdsValue);
    Serial.print(tdsValue-35,0);
    Serial.println("ppm");
    delay(1000);
     
}

thanks for the help.

2

Have you tried running one of the example sketches to make sure that the TFT is connected up correctly and working properly?

3

TFT is displaying everything good, this code is just to pin point the reason the variable tdsValue does not show correctly on the TFT.

4

Ok, fair enough. So what is it displaying on the TFT when compared with Serial Monitor?

5

On serial monitor, its displays like

165ppm
165ppm
165ppm
Etc.

On tft simply does not show nothing. No matter where i setCursor.
Thats why for test purpose i let it start @ 0.0

6

Study the TFT example programs more carefully.

You appear to be missing calls to .display(), which is required to actually send the data to the screen.

7

Try removing or commenting out the line:

tft.begin(9600);

You already have:

tft.begin(0x7793);

8

done that, still with same problem.
i manage to set up the gui and so far this is my first display issue with the screen itself.
ill give a few turns on the tft.print

9

I must admit I used calls to .display() rather than .print() in my sketch, but I was using a different library. This MCUFRIEND example has a call to setCursor(), so you might try adding:

tft.setCursor(0,0);

of whatever position you want to place the text, before your call to print();

Example:
^https://github.com/prenticedavid/MCUFRIEND_kbv/blob/master/examples/Font_simple/Font_simple.ino

10

My mistake, the MCUFRIEND_kbv library does not use the .display() method. I was thinking of another TFT library.

11

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