RP2040 + ST7796 + XPT2046 - Touch values are very odd and I can't get no reason for that

[gymho-gabriel]

Hey community,
after spending 4 hours with this specific issue (maybe only my issue, not TFT_eSPI's) I am asking you. A similar

I am using a cheaper 4'' display (with SD-reader, but not connected) - LCDWiki-Displaymodule
My circuit only consist of a raspi pico and the display.

Connections:
`TFT PICO

VCC - 3V3
GND - GND
CS - GP13
RESET - 3V3
DataCmd - GP17
MOSI - SPI1 TX GP11
SCK - SPI1 CLK GP10
LED - GP16
MISO - N/C

T_CLK - SPI1 CLK GP10
T_CS - GP15
T_DIN - SPI1 TX GP11
T_DO - SPI1 RX GP12
T_IRQ - N/C`

i did not connect MISO on display side and the IRQ pin on the touch side.

My Pin Setup in user_setup.h is as follow:
`#define USER_SETUP_INFO "RP2040-ST7796"
#define ST7796_DRIVER
#define TFT_WIDTH 320
#define TFT_HEIGHT 480
// #define TFT_INVERSION_ON
// #define TFT_INVERSION_OFF
#define TFT_BACKLIGHT_ON HIGH // Level to turn ON back-light (HIGH or LOW)
#define TFT_MISO 12
#define TFT_MOSI 11
#define TFT_SCLK 10
#define TFT_CS 13 // Chip select control pin D8
#define TFT_DC 14 // Data Command control pin
#define TFT_RST -1 // Set TFT_RST to -1 if the display RESET is connected to NodeMCU RST or 3.3V
#define TFT_BL 16 // LED back-light (only for ST7789 with backlight control pin)
#define TOUCH_CS 15 // Chip select pin (T_CS) of touch screen

#define LOAD_GLCD // Font 1. Original Adafruit 8 pixel font needs ~1820 bytes in FLASH
#define LOAD_FONT2 // Font 2. Small 16 pixel high font, needs ~3534 bytes in FLASH, 96 characters
#define LOAD_GFXFF // FreeFonts. Include access to the 48 Adafruit_GFX free fonts FF1 to FF48 and custom fonts
#define SMOOTH_FONT

#define TFT_SPI_PORT 1
#define SPI_FREQUENCY 10000000
#define SPI_TOUCH_FREQUENCY 1000000
//#define SUPPORT_TRANSACTIONS`

i experimented a lot with SPI_FREQUENCIES...

So what is the deal with my setup?

when leaving the display untouched, the values show (with Test_Touch_Controller):
x: 0 y:7936 raw:62463 x: 0 y:7936 raw:62463 x: 0 y:7936 raw:65535 x: 0 y:7936 raw:4351 x: 0 y:7936 raw:62207 x: 0 y:7936 raw:62207 x: 0 y:7936 raw:4607 x: 0 y:7936 raw:4863 x: 0 y:7936 raw:62463 x: 0 y:7936 raw:64255 x: 0 y:7936 raw:61695 x: 0 y:7936 raw:62975 x: 0 y:7936 raw:5119 x: 0 y:7936 raw:62719 x: 0 y:7936 raw:62207 x: 0 y:7936 raw:3071 x: 0 y:7936 raw:5119 x: 0 y:7936 raw:61695 x: 0 y:7936 raw:64255 x: 0 y:7936 raw:4863

When I touch the area:
x: 768 y:7936 raw:8959 x: 4096 y:4096 raw:4607 x: 3840 y:2048 raw:1791 x: 2048 y:0 raw:0 x: 7936 y:2048 raw:12031 x: 2048 y:0 raw:10239 x: 3840 y:7936 raw:9983 x: 7936 y:4096 raw:2815 x: 0 y:2048 raw:65535 x: 0 y:4096 raw:8703 x: 7936 y:0 raw:63743 x: 4096 y:4096 raw:3839 x: 2048 y:2048 raw:3839 x: 6912 y:0 raw:4607 x: 0 y:2304 raw:255 x: 3840 y:7168 raw:6143 x: 7936 y:4096 raw:5887

so this is one fingerpress - several seconds.

Ideas, guys? I do not know what it is. Anyway, Bodmer, the library is great! I think i am too stupid.

Regards,
Peter

EDIT: changed hardware and settings to SPI Bus Number 0. No Change!

EDIT: Changed BSP from Arduino MBED Pico to Earle Philhower's. This changed a lot. Y Values are still > 2000 when untouched. The biggest change ist touch RAW - this value stays below 200.
Experimented with differen Frequency-Values - does not have much effekt. The goal ist to keep both x and y to zero when left untouched. Then the calibration routine will not automatically go through the process...

[gymho-gabriel]

Alright - so anything is odd - try to use Earle's BSP instead of the shipped one in Arduino IDE

[OlivierCROISET]

Connection below that works :
``
// SPI port 1 to the TFT screen
#define TFT_MISO 12 // pin 16
#define TFT_SCK 14 // pin 19
#define TFT_MOSI 15 // pin 20
#define TFT_DC 7 // pin 10
#define TFT_RST 99 // unused pin
#define TFT_CS 13 // pin 17
Adafruit_ILI9341 tft( TFT_CS, TFT_DC, TFT_MOSI, TFT_SCK, TFT_RST, TFT_MISO);

// Connect the touchpad to the default SPI0 port
#include <XPT2046.h>
// Default SPI port to the touchpad
//#define TOUCH_SCK 10 // pin 14
#define TOUCH_CS_PIN 17 // pin 22
//#define TOUCH_MOSI 19 // pin 25
//#define TOUCH_MISO 16 // pin 21
#define TOUCH_IRQ_PIN 98 // unused pin

XPT2046 touch(TOUCH_CS_PIN, TOUCH_IRQ_PIN);
``
Both TFT screen and touchpad will work correctly !