[TriEmbed] Pi Zero W -- Touch Display Troubleshooting

[Huan Truong]

Since you mentioned that you use a handmade usb cable... This could be the 
problem. Reason is that the mini USB-OTG cable actually has 5 pins:

https://www.pinterest.com/pin/511580838893581192/

If you splice a straight USB cable to connect to a usb device, the pi will 
assume it's the slave, not the master.

If you insist on using our DIY cable, try adding this to /boot/config.txt:

[pi0]
dtoverlay=dwc2,dr_mode=host



On Monday, June 6, 2022 6:31:29 PM PDT you wrote:
> Thanks, Huan!
> Unfortunately, dmesg showed nothing, and xev showed one event on the first
> touch, and nothing after.
> I do see (I think) the device coming up in dmesg during bootup, but nothing
> unusual.
> 
> [   22.986800] input: TSTP MTouch as
> /devices/platform/soc/20980000.usb/usb1/1-1/1-1:1.0/0003:0416:C168.0
> 001/input/input1
> [   23.023450] hid-multitouch 0003:0416:C168.0001: input,hidraw0: USB HID
> v1.11 Device [TSTP MTouch] on usb-20980000.usb-1/input0
> 
> Great idea, though. I'd meant to check that, but forgot until you reminded
> me.  Thanks!
> 
> Best,
> Ron
> 
> On Mon, Jun 6, 2022 at 9:17 PM Huan Truong <htruong at tnhh.net> wrote:
> > You could try watching the dmesg for any disconnection of usb
> > 
> > $ sudo dmesg -w
> > 
> > Then touch the screen and see if there's anything weird.
> > 
> > You could also watch for x events.
> > 
> > $ xev
> > 
> > 
> > 
> > 
> > Huan Truong
> > tnhh.net
> > 
> > On Jun 6, 2022, at 5:38 PM, Ron Craig via TriEmbed <triembed at triembed.org>
> > wrote:
> > 
> > 
> > Hi, gang.
> > 
> > I bought this display
> > <https://www.amazon.com/dp/B07L6WT77H?psc=1&ref=ppx_yo2ov_dt_b_product_det
> > ails> from Amazon. It states it works with the Pi Zero, but I cannot get
> > Touch to work on that. Touch works fine on a Pi 4B, but not the Zero.
> > Any hints?
> > 
> > I have made my own cables where needed, but Touchscreen still does not
> > work.  I am including my wiring setup below.  Am I missing something?  The
> > arrow on the OS screen moves the *first *time I touch the screen, but
> > will not move after that.  I think it is a software issue?  Are there
> > drivers needed for the Zero?
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > *pi at hamclock:~ $ cat /etc/os-releasePRETTY_NAME="Raspbian GNU/Linux 10
> > (buster)"NAME="Raspbian GNU/Linux"VERSION_ID="10"VERSION="10
> > (buster)"VERSION_CODENAME=busterID=raspbianID_LIKE=debianHOME_URL="http://
> > www.raspbian.org/
> > <http://www.raspbian.org/>"SUPPORT_URL="http://www.raspbian.org/RaspbianF
> > orums
> > <http://www.raspbian.org/RaspbianForums>"BUG_REPORT_URL="http://www.raspb
> > ian.org/RaspbianBugs <http://www.raspbian.org/RaspbianBugs>"*
> > 
> > *pi at hamclock:~ $ uname -aLinux hamclock 5.10.103+ #1529 Tue Mar 8 12:19:18
> > GMT 2022 armv6l GNU/Linux*
> > 
> > 
> > In the picture:
> > 1: Power Block (5V 3.5A) to MICRO USB power connector on the Zero W.  No
> > under voltage warnings. All looks good.
> > 2: DIY 4-wire cable from JST to MICRO USB connector on the Zero W.
> > Substitute for the 5V+Touch connector on the side.
> > 3: Supplied FPC to MINI HDMI connector on the Zero.  Reaches fine once I
> > moved the Zero to another location (was too short if the Zero was
> > installed
> > where suggested).
> > 
> > [image: Zero Connections small.png]
> > I've put Kapton tape on the back of the Zero W to prevent any electrical
> > shorts with the unused mounting post.
> > 
> > On bootup to 32-bit Raspberry OS, the desktop appears properly and the
> > picture looks great.  I can touch the screen EXACTLY ONE TIME, and the
> > arrow cursor will move to where I touched the screen.  It never moves
> > after
> > that.
> > 
> > The application I use does not require a keyboard if I can use a
> > touchscreen. Without touch, I need a bluetooth mouse, which I would rather
> > not use. There are less expensive non-touch screens I think I could use if
> > touch will not work.
> > 
> > Any help is greatly appreciated. I've already printed a nice case and
> > swinging mounting arm for this display, so I would love to keep it and use
> > it if I can get touch to work.
> > 
> > Note that I've also tried power through the 5V IN connector, but the
> > behavior is exactly the same.
> > 
> > Generally, are there any gotchas with Touch and the Zero or Raspberry OS
> > in general I could try?
> > 
> > Best,
> > --
> > Ron Craig   KO4RON
> > J'ai bonne espérance!
> > 
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