XPT2046 touch interrupt on pin 11 keeps 3b+ from initializing

[/RaspberryPi]

So I got one of the knockoff waveshare 3.5" touchscreens (I know, I know, now.) and have managed to get it to run. Sort of.

Initial install was the usual white screen only issue. Figured out that the pi was not even starting a boot sequence. No green light at all.

Then I found that if I powered it on with the screen disconnected even for just a second, I could then attach the screen and it all worked fine.

Once that has been done I can do a reboot and it starts up and works correctly. But if I do a shutdown it will not start again until the screen is pulled and replugged.

So I got some dupont wires and uaed those to connect the screen and started narrowing down the cause. I did not connect the 3v3 lines or the pins marked not used in the screen spec.

I found that when pin 11 is not connected it will start up just fine. But then there is no touch capability as that is the TP_IRQ signal. If I plug it in after starting, touch comes back just fine.

So now i basically can not case this thing up because I have to remove the screen to get it to start.

No amount of searching has found any similar issue.

Anybody have ANY ideas at all here?

Screen is non returnable and I'm trying not to throw good money after bad.
submitted by /u/mrkrag
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Source: https://www.reddit.com/r/raspberry_pi/c ... s_3b_from/