Raspberry Pi Forums

Posted: **Tue Jan 17, 2017 10:26 am**

I have RPi B+ + 3.5 LCD TFT. Touch panel on LCD worked ok, but since one week it doesn't work correctly. Touch panel reacts after several touches after startup the system. Then the system only press on touch screen but without release, so when I touch in other point on screen system selects an area e.g. like in win when press in some point and move the mouse. There is not possible to select some icon on the desktop.

There is any configuration of touch events? Does anybody meets with mentioned behaviour? Maybe there is any option in xset or xinput?

OS: Raspbian Wheezy, LCD: http://www.waveshare.com/wiki/3.5inch_RPi_LCD_(A)

Many thanks in advance for any help.

Posted: **Tue Jan 17, 2017 1:21 pm**

Hi and welcome to the forum.

You need to be more specific with the LCD model you have - there are many versions of '3.5" LCD' out there. Which OS are you using - one from the supplier?
Best to speak to the guys where you got it from. It could be a software issue, or just a faulty unit.
Texy

Posted: **Wed Feb 15, 2017 9:40 pm**

I used to evtest command and just after reboot for first touch I received the following log:

No device specified, trying to scan all of /dev/input/event*
Not running as root, no devices may be available.
Available devices:
/dev/input/event0: ADS7846 Touchscreen
Select the device event number [0-0]: 0
Input driver version is 1.0.1
Input device ID: bus 0x0 vendor 0x0 product 0x0 version 0x0
Input device name: "ADS7846 Touchscreen"
Supported events:
Event type 0 (EV_SYN)
Event type 1 (EV_KEY)
Event code 330 (BTN_TOUCH)
Event type 3 (EV_ABS)
Event code 0 (ABS_X)
Value 0
Min 0
Max 4095
Event code 1 (ABS_Y)
Value 0
Min 0
Max 4095
Event code 24 (ABS_PRESSURE)
Value 0
Min 0
Max 65535
Properties:
Testing ... (interrupt to exit)
Event: time 1487194526.983429, type 1 (EV_KEY), code 330 (BTN_TOUCH), value 1
Event: time 1487194526.983429, type 3 (EV_ABS), code 0 (ABS_X), value 954
Event: time 1487194526.983429, type 3 (EV_ABS), code 1 (ABS_Y), value 4095
Event: time 1487194526.983429, type 3 (EV_ABS), code 24 (ABS_PRESSURE), value 64

508
Event: time 1487194526.983429, -------------- EV_SYN ------------
Event: time 1487194526.993492, type 3 (EV_ABS), code 0 (ABS_X), value 2580
Event: time 1487194526.993492, type 3 (EV_ABS), code 1 (ABS_Y), value 2669
Event: time 1487194526.993492, type 3 (EV_ABS), code 24 (ABS_PRESSURE), value 64

702
Event: time 1487194526.993492, -------------- EV_SYN ------------
Event: time 1487194527.003504, type 3 (EV_ABS), code 0 (ABS_X), value 2581
Event: time 1487194527.003504, type 3 (EV_ABS), code 1 (ABS_Y), value 2647
Event: time 1487194527.003504, type 3 (EV_ABS), code 24 (ABS_PRESSURE), value 64
945
Event: time 1487194527.003504, -------------- EV_SYN ------------
Event: time 1487194527.013537, type 3 (EV_ABS), code 0 (ABS_X), value 2571
Event: time 1487194527.013537, type 3 (EV_ABS), code 1 (ABS_Y), value 2645
Event: time 1487194527.013537, type 3 (EV_ABS), code 24 (ABS_PRESSURE), value 64
944

There is no a line with (EV_KEY), code 330 (BTN_TOUCH), value 0 which corresponds to release finger from touch panel.

Posted: **Thu Feb 16, 2017 7:25 am**

If the display worked initially, then stopped working, then surely 1 of 2 things have happened
1..the display has developed a fault or bad connection to the pi
2..the os has changed in such a way to corrupt the drivers required.

Are you able to start from scratch with the specific OS for the display?

Texy

Posted: **Tue Feb 21, 2017 2:19 pm**

Display worked fine earlier. So I assumed that there is not a problem with connection.
I used pure software with drivers and again with Waveshare software and the problem occurs too.

Is there any possibility to send EV_KEY BTN_TOUCH command with value 0 (release) via command line and then do touch again?

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