Issue with calibration of display (ili9341 display and xpt 2046 touch controller)

Bug (archived)
41

Good Morning, according to the correct documentation (https://www.espressif.com/sites/default/files/documentation/esp32-wroom-32d_esp32-wroom-32u_datasheet_en.pdf), I’ve now wired the pins correct:

#define DISP_SPI_MOSI 13
#define DISP_SPI_CLK  14
#define DISP_SPI_CS   15

#define ILI9341_DC   17
#define ILI9341_RST  25
#define ILI9341_BCKL 26

#define TP_SPI_MOSI 23
#define TP_SPI_MISO 19
#define TP_SPI_CLK  18
#define TP_SPI_CS   5

#define XPT2046_IRQ 27

I’ve also defined these values:

#define XPT2046_X_MIN  0
#define XPT2046_Y_MIN  0
#define XPT2046_X_MAX  4095
#define XPT2046_Y_MAX  4095

Now it’s working and i get these values shown on my display with tpcal:

left upper: x=274 y=196
right upper: x=51 y=195
right lower: x=47 y=35
left lower: x=275 y=35

For your Information: I’ve an ESP32 DevKit v4 with ESP32-WROOM-32d.

1 Like
42

Sorry, my mistake: In my last post

xpt2046_x_inv and xpt2046_y_inv

were commented out. I’ve changed it back to “1”, now I get correct values and the example application (LV_USE_DEMO) works correctly:

left upper: x = 41 y = 43
right upper: x = 265 y = 42
right lower: x = 266 y = 202
left lower: x = 41: y = 202
2 Likes
43

Great, nice one :slight_smile:

1 Like
44

Hi,

I am having raw values that dont calibrate the tp.

#define XPT2046_X_MIN 722
#define XPT2046_Y_MIN 636
#define XPT2046_X_MAX 3602
#define XPT2046_Y_MAX 3417

I already decreases the spi touch frequency to 1 Mhz.

I need add a delay in “xpt2046_read” function ?

Thank’s.

45

What do you experience? Is there a small or a big error?

You can verify the calculations here.

46

In really, after i decrease de touch spi frequency to 1 MHz, the initial values 0 to 4095, in both x and y, behave much better than the calibrated values.

Are these calibrated values ​​reasonable?

#define XPT2046_X_MIN 722
#define XPT2046_Y_MIN 636
#define XPT2046_X_MAX 3602
#define XPT2046_Y_MAX 3417

47

@Baldhead hey so after running adding a delay in xpt touch function and adding following values
#define XPT2046_X_MIN 0
#define XPT2046_Y_MIN 0
#define XPT2046_X_MAX 4095
#define XPT2046_Y_MAX 4095

it works perfectly for me.

48

hello, I also had problems with the touch, I changed the speed of the SPI to
.clock_speed_hz=2x1000x1000, in tp_spi.c
and everything was solved, for example my configuration was

#define XPT2046_X_MIN 346
#define XPT2046_Y_MIN 197
#define XPT2046_X_MAX 3912
#define XPT2046_Y_MAX 3843
#define XPT2046_X_INV 1
#define XPT2046_Y_INV 1

thanks

1 Like
49

@JocPlusPlus
Thank you for the feedback.
I’ve updated the project to use 2 MHz clock on Touchpad SPI.

1 Like