touch not working

[alen1359]

i am using 2.8 inch TFT 320x240 version 1.1 with xpt 2046 touch drive, but the touch part is not working, could you please advice?

i thought it was the screen and bought another one but i have the same issue

link for my screen: https://www.esp8266.com/viewtopic.php?f=160&t=14302

[alen1359]

seems like the touch work but there is big offset between where i touch and it react

[alen1359]

if i touch top left i get x=320, y=239, if i touch top right i get x= 4, y=240, if i touch bottom left i get x=320, y=-416 (note: it is negative 416), if i touch bottom right i get x=2, y=-235

seems like need calibration, could you please help

[kisvegabor]

It seems you just need to swap the x coordinate. You can do it easily here: https://github.com/littlevgl/esp32_ili9341/blob/master/drv/xpt2046.c#L95

x = 320-x;
if( x < 0) x = 0;
if(x  > 319) x = 319;
last_x = x; 

[alen1359]

with that correction i get the following result

if i touch top left i get x=0, y=239, if i touch top right i get x= 320, y=240, if i touch bottom left i get x=0, y=-416 (note: it is negative 416), if i touch bottom right i get x=320, y=-293

here where i added:

        /*Normalize Data*/
        x = x >> 3;
        y = y >> 3;
        xpt2046_corr(&x, &y);
        xpt2046_avg(&x, &y);
		
		x = 320-x;
		if( x < 0) x = 0;
		if(x  > 319) x = 319;
		last_x = x; 

        //last_x = x;
        last_y = y;

[alen1359]

more accurate data using pen for touch

if i touch top left i get x=0, y=239, if i touch top right i get x= 320, y=240, if i touch bottom left i get x=0, y=-416 (note: it is negative 416), if i touch bottom right i get x=320, y=-416

[kisvegabor]

I see. It really still need to be calibrated.
The calibration values are here:
https://github.com/littlevgl/esp32_ili9341/blob/master/drv/xpt2046.h#L27-L32

You should try to set the MIN coordinates to 0 and MAX to 4096 to disable calibration, check the coordinates and write them as calibration values.

I forget that here you can also invert the X and/or Y coordinates if required. So the previous hack is not required.

[alen1359]

ok, if i do min=0 and max 4096 i get teh followings

#define XPT2046_X_MIN 39
#define XPT2046_Y_MIN 21
#define XPT2046_X_MAX 271
#define XPT2046_Y_MAX 226

but when i put them in my code it doesn't work still i also tried the followings but no success

#define XPT2046_X_MIN 390
#define XPT2046_Y_MIN 210
#define XPT2046_X_MAX 2710
#define XPT2046_Y_MAX 2260

Note, X invert need to be 0

thanks for all your help

[kisvegabor]

What was the problem with the first version?

[alen1359]

ok i ran it again with 0 and 4096, here are the numbers,
bottom left x=38, y=21
top left x=38, y=211
top right x=250, y=226
bottom right x= 272, y=29

if i enter these numbers in my code and compile i get the followings
#define XPT2046_X_MIN 38
#define XPT2046_Y_MIN 21
#define XPT2046_X_MAX 272
#define XPT2046_Y_MAX 226

i get

bottom left x=379, y=-4118
top left x=378, y=-333
top right x=4334, y=-33
bottom right x= 5024, y=-4081

which make no sense

[kisvegabor]

I have no idea. The correction happens here: https://github.com/littlevgl/esp32_ili9341/blob/master/drv/xpt2046.c#L116

With the parameters, you provided it should work. You can debug it using printfs to see where the miscalculation happens.

[alen1359]

i can't figure out what is going on, is it possible to recommend me a display that works with this code.

thanks,

[alen1359]

i set the invert for Y to 1 and i believe this is where the problem is, it is creating a negative number for Y

#if XPT2046_Y_INV != 0
(*y) = XPT2046_VER_RES - (*y);

[alen1359]

top left should be 0,0 or bottom left ?

[kisvegabor]

top left should be 0,0 or bottom left ?

Top-left should be (0,0).

i can't figure out what is going on

You should printf the raw and corrected data step by step to where the problem occurs.

is it possible to recommend me a display that works with this code.

Resistive TPs might be different even for the same product type.

[stale]

This issue or pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[C47D]

I also noticed the touch isn't working, in my case when i touch the screen from right to left the red dots appear from top to bottom, when i touch the screen from bottom to top the red dots appears from right to left.

I haven't tried to log the input device output, is there a 'easy' way to do it?

Regards

[embeddedt]

@C47D Use printf or something similar inside the indev_read function.

[C47D]

Thanks, i will take a look at it.

[stale]

This issue or pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.