XPT2046 touchscreen problem

[Sandro]

Hi all, I'm trying to get a 2.8TFT SPI 240x320 touch display working with T41, SPI1.

If I use this code:

#include <XPT2046_Touchscreen.h>
#include <SPI.h>

// T_CLK --> 27
#define CS_PIN    35 // T_CS
// T_DIN --> 26
// T_DO --> 39
#define TIRQ_PIN  33 // T_IRQ

 XPT2046_Touchscreen ts(CS_PIN);  // Param 2 - NULL - No interrupts
// XPT2046_Touchscreen ts(CS_PIN, 255);  // Param 2 - 255 - No interrupts
// XPT2046_Touchscreen ts(CS_PIN, TIRQ_PIN);  // Param 2 - Touch IRQ Pin - interrupt enabled polling

void setup()
{
  Serial.begin(38400);
  ts.begin(SPI1);
  ts.setRotation(0);
  while (!Serial && (millis() <= 1000));
}

void loop()
{
  if (ts.touched())
  {
    TS_Point p = ts.getPoint();
    Serial.print("Pressure = ");
    Serial.print(p.z);
    Serial.print(", x = ");
    Serial.print(p.x);
    Serial.print(", y = ");
    Serial.print(p.y);
    delay(30);
    Serial.println();
  }
}

the result is a continuous print, even without any touch:

Pressure = 4095, x = 4095, y = 0
Pressure = 4095, x = 4095, y = 0
Pressure = 4095, x = 4095, y = 0
Pressure = 4095, x = 4095, y = 0
Pressure = 4095, x = 4095, y = 0
Pressure = 4095, x = 4095, y = 0
Pressure = 4095, x = 4095, y = 0
Pressure = 4095, x = 4095, y = 0
Pressure = 4095, x = 4095, y = 0

If I use this code:

#include <XPT2046_Touchscreen.h>
#include <SPI.h>

// T_CLK --> 27
#define CS_PIN    35 // T_CS
// T_DIN --> 26
// T_DO --> 39
#define TIRQ_PIN  33 // T_IRQ


// XPT2046_Touchscreen ts(CS_PIN);  // Param 2 - NULL - No interrupts
// XPT2046_Touchscreen ts(CS_PIN, 255);  // Param 2 - 255 - No interrupts
XPT2046_Touchscreen ts(CS_PIN, TIRQ_PIN);  // Param 2 - Touch IRQ Pin - interrupt enabled polling

void setup()
{
  Serial.begin(38400);
  ts.begin(SPI1);
  ts.setRotation(0);
  while (!Serial && (millis() <= 1000));
}

void loop()
{
  if (ts.touched())
  {
    TS_Point p = ts.getPoint();
    Serial.print("Pressure = ");
    Serial.print(p.z);
    Serial.print(", x = ");
    Serial.print(p.x);
    Serial.print(", y = ");
    Serial.print(p.y);
    delay(30);
    Serial.println();
  }
}

and also add a line in XPT2046_Touchscreen.cpp:

void isrPin( void )
{
	XPT2046_Touchscreen *o = isrPinptr;
	o->isrWake = true;
    Serial.println("$");  // <-- Added this line
}

then the result is a gain a continuous output without any touch:

Pressure = 4095, x = $
4095, y = 0
$
$
$
$
$
$
$
$
$
$
Pressure = 4095, x = $
4095, y = 0

Just for completeness, everything works with stadard SPI connection; using this code/connections:

#include <XPT2046_Touchscreen.h>
#include <SPI.h>

#define CS_PIN  8
// MOSI=11, MISO=12, SCK=13

//XPT2046_Touchscreen ts(CS_PIN);
#define TIRQ_PIN  2
XPT2046_Touchscreen ts(CS_PIN);  // Param 2 - NULL - No interrupts
//XPT2046_Touchscreen ts(CS_PIN, 255);  // Param 2 - 255 - No interrupts
//XPT2046_Touchscreen ts(CS_PIN, TIRQ_PIN);  // Param 2 - Touch IRQ Pin - interrupt enabled polling

void setup() {
  Serial.begin(38400);
  ts.begin();
  ts.setRotation(1);
  while (!Serial && (millis() <= 1000));
}

void loop() {
  if (ts.touched()) {
    TS_Point p = ts.getPoint();
    Serial.print("Pressure = ");
    Serial.print(p.z);
    Serial.print(", x = ");
    Serial.print(p.x);
    Serial.print(", y = ");
    Serial.print(p.y);
    delay(30);
    Serial.println();
  }
}

the touch functionality is perfect:

Pressure = 2431, x = 599, y = 1384
Pressure = 1618, x = 547, y = 1332
Pressure = 2147, x = 539, y = 1344
Pressure = 2219, x = 537, y = 1348
Pressure = 2153, x = 531, y = 1336
Pressure = 2026, x = 530, y = 1330
Pressure = 1800, x = 531, y = 1320
Pressure = 1744, x = 534, y = 1314
Pressure = 1845, x = 533, y = 1312
Pressure = 1903, x = 533, y = 1304
Pressure = 1920, x = 534, y = 1304

Cannot find the mistake... Any suggestion would be appreciated.
Thanks in advance