BitsyXb - User Manual
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4.6
Displays
The BitsyXb uses the integrated display controller to drive liquid crystal displays (LCDs).
Connector J1 supplies the power and data signals needed to drive LCDs, while backlight and
touch panel control signals are located on connector J3.
4.6.1
Display Types Supported
Eurotech has configured the BitsyXb for a wide variety of display types and sizes. Consult the
Eurotech support site (section 2.4) for the latest list of displays supported by Eurotech. If a
display is not on the list, contact Eurotech Sales for information about Eurotech' panel
configuration service.
The display controller uses system memory for the display frame buffer and can drive VGA
(640x480) and SVGA (800x600) displays easily. Larger displays will work with the processor,
with some constraints imposed by the controller architecture. The Eurotech Support Forums
provide details about the design tradeoffs that are required to support larger displays.
The BitsyXb can drive LVDS displays using an Eurotech adapter circuit.
4.6.2
LCD Voltages
The BitsyXb supplies 3.3 V or 5 V power to the LCD display via J1. Select this voltage with JP2
(section 3.2.1). Please observe the cautions listed with the JP2 settings.
4.6.3
Display Signals
Display signals
LDD0
through
LDD15
—as well as the pixel clock, vertical sync and horizontal
sync—are all buffered at a factory-set voltage. See section 6.3.2 for full specifications.
The
PNL_RL
and
PNL_UD
signals are for active (TFT) displays that support changing the scan
direction. This feature allows the display to be flipped right-to-left (
RL
) or up-and-down (
UD
) by
changing the voltage on these signals. See section 6.3.2 for full specifications.
4.6.4
Creating Display Cables
Eurotech has designed cables for a wide variety of displays. See the list of supported displays on
the Eurotech support forums. Cable drawings for supported displays are available on request.
While Eurotech does not provide support to customers to create their own cables, designers with
LCD display experience may be able to design their own. For those that do so, a key point to keep
in mind is that the PXA270 LCD interface maps its display controller pins differently based on
LCD technology and color palette size. Consult the PXA270 User’s Manual for more
information.
4.6.5
Developing Display Drivers
The processor has a bank of registers that define the timing for displays. In addition, the operating
system must define the region of memory for the frame buffer(s).
16
Currently posted at http://www.applieddata.net/forums/topic.asp?topic_id=580
17
Intel PXA27x Processor Family: Developer's Manual. Order number 280000-001, April 2004.
pp. 7-49 to 7-53.
