Touch screen display for Hikey960

96boards

#1

Hello,

I want to know, if I powered this display using external USB such as using Laptop’s USB, then will touch works properly?
Or is there any alternative way to connect this board without using any USB port from Board?

Thanks,
Raj


#2

USB is not just for power but also for the touchscreen ‘protocol’ (USB HID), so If you plug USB to a Laptop, you’ll control your laptop not the board.

Why you don’t want to use USB port of the board ? if this is a power limitation issue you can insert a USB powered HUB between the Hikey and the touchscreen.


#3

I’ve had problems running USB-powered displays on a hikey960. The issue is that the display’s hdmi controller isn’t powered up until the USB power is switched on, which happens too late for the hdmi to be initialized. What I’ve done to deal with this situation, is to power the display from the +5 available on the LS plug, since that 5v is available immediately.

@Raj_Kadu I don’t know much of the details about that display, if it has a jack or pins for adding external power directly (not the USB), then you can hook that into the low speed connector, or any other external power supply. If not, then you may have to modify the USB cable. If you strip the insulation off the cable, you will find 4 wires in it. If one of them is RED, that will be your +5, and if one of them is BLACK, that will be your 0. CUT the red wire, and connect the display side of it to the +5 on the low speed connector (pin 37). Bind the other side of the wire with insulating tape. That should be all you need to do (no need to reroute the black wire, since it will already be common). If you want to use an EXTERNAL power source, then you will also need to tap into the BLACK wire in order to establish a common ground, BUT DO NOT DISCONNECT IT. The black wire should still connect right through.


#4

Thank you @doitright

After doing this, will touch work for Hikey960?


#5

As long as you keep the USB data pins connected, touch should work.


#6

Thanks @Loic for your answer.
Whenever I am connecting C-Type connector for ADB, it is disabling the USBs. I want to interact with board while adb is connected.


#7

You will need to either use ADB over IP (network / wifi), or you will need to use UART instead of USB/ADB. Unfortunately, the kirin 960 SoC only has ONE USB port, which means that it can either be set to DEVICE mode (USB-C plug), or HOST mode (USB-A plugs), but never both at the same time.

You can add this to your /system/build.prop to enable ADB over IP:
service.adb.tcp.port=5555

Then reboot, and use it by running;
adb connect ip_address_of_hikey960

Or for uart:
https://www.seeedstudio.com/depot/96Boards-UART-p-2525.html
Then you run “screen /dev/ttyUSBx 115200” to connect to it.


#8

Ohh thats what I want… :smiley:

But I doubt, will touch work properly with UART as it works with USB?


#9

Uart has NOTHING to do with touch.


#10

Then will touch work or not using UART?


#11

Touch uses USB. Touch does not use UART.


#12

Thats correct,
Here is what I understood, connect the display using HDMI and power it using USB (UART to USB), as touch also uses the same USB, touch will also work using UART to USB converter.

Correct me if I missed anything.