Difference between revisions of "Engage 10"

Revision as of 12:58, 13 December 2016

Engage 10 Wireless LCD Model number : W10T200-HWH1WH

These devices were intended to be WUSB touchscreens. They include an internal WUSB device dongle, an NEC USB hub, a USB displayport video chip feeding VGA to an RTD LCD driver, and a USB HID touchscreen.

The LCD seems to be 1024 x 600 native resolution. There are some macro buttons, but I have not seen them driving any linux input streams.

The box should include the display, an external WUSB host dongle, a 12 volt (usually 3 amp) power supply and a USB A to USB A cable. The cable was included just to allow pairing between the WUSB dongles, but it can be used to connect the display directly to the computer.

The pairing process seems to be tricky...

The displayport chip is a DL-125, old and well supported.

• The current raspbian image has a kernel module driver for it.

• Current Ubuntu distrubtions seem to hot plug the display and bring up GUI to configure it, but guess the resolution badly.

• Current Debian distrubtions seem to have the driver which generates a green screen, but they do not bring up any GUI to configure it.

• Windows XP needs a displayport driver, I have not tried newer versions on the metal, and had trouble with 7 on a VM.

In general, plugging the display into a linux computer should cause a new fb device to show up in /dev/ and you can then do what you like with it, including x11. A solid green screen is generally a good sign.

Wired USB Connection

I have not actually gotten WUSB to work. I have not tried very hard because it does not seem very useful.

Instead, I have been using the included USB cable. There is some weirdness here. I have seen the external USB port (labeled ¨WUSB¨) work just fine. I have also just seen the external port on a new looking display not work.

Opening the case, removing the dongle from the internal port and plugging the cable in there seems to permanently disable the external port. This might be some magic in U28, but I have not dug into it. By just looking at the board, it seems that both USB ports are connected to the host pins on the USB hub chip.

However, the internal port seems to always work, so it seems like the best bet.

If lsusb lists a displaylink device USB is working.

Raspberry Pi Config

To configure raspbian to use the display create /usr/share/X11/xorg.conf.d/60-pluggable.conf with the following text:

Section "Device" 
  Identifier "displaylink device" 
  driver "fbdev" 
  Option "fbdev" "/dev/fb1" 
  Option "ShadowFB" "off"
EndSection 

Section "Monitor" 
  Identifier "displaylink monitor" 
EndSection 

Section "Screen" 
  Identifier "displaylink screen" 
  Device "displaylink device" 
  Monitor "displaylink monitor"
  DefaultDepth    16
  SubSection "Display"
    Depth    16
    Modes     "1024x600"
  EndSubSection
EndSection 

Section "ServerLayout" 
  Identifier "default" 
  Screen 0 "displaylink screen" 0 0 
EndSection

That should take care of the display.. I just made up most of the config, it is probably not optimised.

Hacking

Touch Screen

The touch screen seems to stream HID absoulte X and Y events.. Raspbian seems to convert these to mouse events by default, and gets the axis wrong. This can probably be fixed in software, but it is an area that needs work.

USB

I have removed R311 and jumped pins 1 of the USB ports together to allow a pi to be powered from the external port.

The USB hub is an NEC 720114, which should have 4 downstream ports. It would be nice to bring out the two unused ports for a keyboard and mouse (or anything else).

VGA

I have cut the traces on the displaylink (left) side of J5 and fed VGA into J5. This has worked briefly a few times, I think I was just having trouble generating acceptable resolutions. I think it has promise.

Interestingly, the ¨Searching¨ icon was still present, so it must come from the RTD2033V chip.

Power

12 volt current draw is about 550mA for the screen and 800mA for the screen and a pi 2B.