I wanted to attach an LCD touch screen to the top of the kit.  The lid has a diagonal of about nine inches (22cm) so a 6, 7 or 8 inch screen will do. 

The LCD

The options are:

  1. A  portable LCD screen unit with a VGA interface such as:
  2. An LVDS LCD display such as:
  3. A TFT Flat Panel Display such as:
  • The first type is simplest as it requires no internal changes to the box.  These are priced at about $A400 upwards.
  • The second type is more integrated into the system.  The Vortex86DX-Spark Kit has an LVDS socket on the processor board.
  • The third type is even more integrated into the system.
  • The second  type requires a (hardware) backlight driver to generate the higher voltages required to drive the light in the back of the screen.
  • A further consideration is that the display will run from battery (DC) voltage such as 12V or 5V.  Therefore a main powered display is out.
  • I decided that I would get best support by getting a screen from the kit supplier (ICOP).  This proved to be quite pivotal in getting the display working.
    • Note that the SBC manual supplies lists of TFT Flat Panels and LVDS Panels that are compatible.
    • You need to specify which ICOP SBC you are ordering it for.

Decision: I chose an 8.4” LVDS display from ICOP, LCD-AU084-SET (Qualification later).  I actually wanted a 6.4” display but it wasn’t available until later.

The Touch screen

A 4 wire resistive (single touch) touch panel will do.  A USB interface is desirable.

A key issue is whether there is a Windows CE driver for the touch screen.  The off-the-shelf screen (as in 1.) don’t tend indicate CE compatibility for touch.  Enquiries suggested to try the CE driver at:
http://home.eeti.com.tw/web20/eg/drivers.htm
but no guarantees were given.

The ICOP LVDS displays come with a touch screen option that has a USB interface.

Read the fine print!

I ordered the LCD-AU084-SET form ICOP in Taiwan and it arrived about 5 days later. This cost about $US200 plus shipping.  I also ordered a Mini PCU WiFi card for about $US30 as part of the same order.  (This fits into the internal Mini PCI slot).

On examination I realised it didn’t have the touch panel.  I should have ordered LCD-AU084-U-SET; the extra U was missing.  The touch panel was shipped later and cost about $US40  plus shipping.  !@#$%^*&$#@!

image

In the next few Blogs I will cover setting up the display and touch screen with the kit.  I use the LVDS display as above. 
This sequence does not cover using the TFT Flat Panel.

Addendum

Here is a diagram of how a resistive touch panel works  (Ref https://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=139 .. Thanks A1ronzo )

The four pins control 4 buss bars located around the peripheral of the touchscreen. In order to read either an x or a y position, two opposing bars need to be powered and a third orthogonal bar is used to measure the divided voltage.

http://www.sparkfun.com/tutorial/USB%20Touchscreen%20Mouse/bussbarssmall.jpg

This configuration means that the voltage, ground, and sense bar need to be continually switched in order to quickly read x and y positions. Here is how I hooked up the touchscreen