PID: 2090 Raspberry Pi 3B+

[llounsbury]

Resolved and works! See bottom of post


I was given a 2.8" Capacitive touch screen, and am wishing to use it with a Raspberry Pi 3b+.
The screen works great! But I am unable to get any touch response.
Here is what I have done so far

Ive wired the display according to this guide (technically for the 3.5" display):
https://pinout.xyz/pinout/pitft_plus_35

Matching the pins via the pinouts : (brief note here, SDA appears to be listed twice?)
https://learn.adafruit.com/adafruit-2-d ... v2/pinouts

As I am using a pi3b+ the prebuilt piTFT images are not supported so I've attempted to run the easy install script, selecting the options for the 2.8" capacitive screen and HDMI mirror mode.

Upon running the script, the screen works great!
But the touch screen doesn't function.

Trying the steps here,
https://learn.adafruit.com/adafruit-2-8 ... ouchscreen
I am getting interesting results,
"$dmesg | grep ft6" returns no results
"$dmesg | grep ft5" gives me this message:

Code: Select all

 
edt_ft5x06 1-0038: touchscreen probe failed
edt_ft5x06: probe of 1-0038 failed with error -121
 

In my /etc/udev/rules.d/ I see this file: 95-ftcaptouch.rules..

Code: Select all

 
SUBSYSTEM=="input", ATTRS{name}=="EP0110M09", ENV{DEVNAME}=="*event*", SYMLINK+="input/touchscreen"
 

Ive tried changing EP0110M09 to ft5x06_ts to no avail

running "$ls -l /dev/input"
does not show touchscreen

Any ideas?

UPDATE: a few hours later
Ive managed to maybe? compile ft6236 with this tutorial
https://gitlab.com/dsehloff/HEM-GUI/wikis/home
(note links are broken, some installs are different..)

now running "$dmesg | grep ft6" gives:

Code: Select all

[   47.578516] ft6236: loading out-of-tree module taints kernel.
[   47.580467] ft6236 1-0038: failed to read from controller: -121
[   47.580500] ft6236: probe of 1-0038 failed with error -121

Resolved!
Currently have the screen working with the most recent stable release of raspbian (2018-10-09-raspbian-stretch).
Running the piTFT easy installer script works (select the 2.8" capacitive screen), and it's all you need to run. Turns out the pin diagram referenced earlier in the post was a bit misleading, and with a bit of fiddling, I've gotten it working. Hope this is able to help someone else out!
Heres the correct pin map for the 2090 on a Pi3B+

Hook up power and ground, 3.3v & 5v out from the Pi (for some reason when I only use 5V I get strange color artifacts...)

PI3B+ PIN : 2090 PIN (using all pins on left side of screen, side without D0-D7)
3 : SDA
5: SCL
18 : IRQ
19: MOSI
21: MISO (doesn't appear to be needed... Im running fine without it)
22: D/C
23: CLK
24: CS

(Ive since also tested on a Pi2B and this pin map works)

[conrad141]

You mentioned connecting the 3.3v and 5v out pins. Did you mean connecting the 3.3v to the pin on the display labeled 3vo?

[llounsbury]

Correct. 3v3 from the Pi to the 3vo on the screen.
The screen works for me without doing this, but artifacts appear often on the screen.
Not sure why it works, but for me at least it does.