LCD Panels for CM-X270 & EM-X270
CompuLab provides the following means to evaluate and adapt LCD panels:
- Ready for use 640 x 480 TFT panel, including cable and s/w setup.
- Generic driver enabling adaptation of new panels.
- Verification and o/s adaptation service performed by CompuLab.
The generic driver enables application programs to access the specified LCD panel as a standard display. CompuLab provides support for the driver’s setup per operating system.
Panel Compatibility Verification
CompuLab will verify the compatibility of a specific panel with a graphics controller. The service works as follows:
- User selects a panel which meets his requirements.
- User checks panel compatibility according to below-listed guidelines.
- The panel datasheet is emailed to CompuLab.
- CompuLab engineers compare the panel datasheet with the graphics controller specifications and respond with compatibility comments.
The verification service is provided to buyers of an evaluation kit, and is limited to three panels.
Adaptation Service by CompuLab
CompuLab provides setup values for the graphics controller, which configure the generic driver to support a particular LCD panel. This service is provided for one panel, whose compatibility has been confirmed previously.
Required User Actions and Tools
CompuLab operating system packages contain facilities and tools enabling the setup of the graphics controller to support the required panel. For Linux, the user can either set values by utility or compile them into the kernel. For Win CE, the user sets the values by registry keys. These can be fed into the operating system by the bootloader or compiled into a run-time image. In most cases, the user can accomplish panel the adaptation task merely by using the facilities provided by CompuLab. However, in certain cases, kernel compilation (Linux) or platform re-build (Win CE) may be required.
Guidelines for Panel Selection
The graphics controller of PXA270 is compatible with most panels available in the market. Final selection should be confirmed by CompuLab. Selection guidelines:
STN / DSTN
|Resolution (max)||800 x 600|
|Bits per pixel (max)||16|
The PXA270 graphics controller has several limitations. For details, please refer to the “Limitations of Display Controller Capabilities” section of the CM-X270 Reference Guide. Same limitations apply for EM-X270.
Panels having resolutions lower than 320 x 240 are supported by controller; however, they sometimes require complicated adaptation, in which case CompuLab reserves the right to refuse providing of adaptation service.
Panel selection tips:
- Portrait and landscape modes are always supported for all panels.
- A typical TFT panel is expected to contain signals such as: R[5:0], B[5:0], G[5:0], CLK, Hsync, Vsync & Data Enable. Check in the datasheet that these signals are available. Take into account that the naming convention may vary.
- Some panels require an additional timing controller chip. Pay attention if the panel’s datasheet specifies this requirement.
- Check that the panel’s input “1” levels are compatible with the 3V levels of CM/EM X270. Otherwise, level shifters may be required.
- Panels usually have 18-bit color while module supports only 16. Therefore, two least significant color inputs should be connected to “0”.