Embedded Panel Interface
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EPI Embedded Panel Interface |
The Embedded Panel Interface EPI, an open standard, allows for easy and direct control of all flat panel displays with maximum interchangeability.
One of the biggest advantages of COM‘s (Computer On Modules) is the inter-changeability of modules between different suppliers. The only weak point was the direct control of flat panel displays. Due to the lack of a uniform standard all manufacturers had to define their own interface strategy.
This problem is now solved with the use of Embedded Panel Interface EPI. EPI is based on the VESA standard EDID 1.3 and defines the software format for display properties and the scalable hardware interface.
With EDID 1.3 only monitors with local intelligence can be operated. In order for an Embedded Computer Module to have direct control of a flat-panel display some more information is required. Therefore, EPI adds the missing parameters to the complete set of EDID 1.3 data.
An EPI data set, used to describe the control of a flat panel display, can be easily created using the information found in the display‘s datasheet. It‘s even easier when using congatec‘s system utility.
With this tool the newly created data set can be written to a reserved area in the congatec embedded BIOS.
The EPI data set description is independent from the video controller and is interpreted by the video BIOS of the COM in order to set the correct video attributes. The result is a manufacturer independent “plug-and-display” solution that enables free interchangeability of displays and COM‘s.
EPI at a glance
What is EPI?
EPI = Embedded panel Interface. It defines the direct connection of flat panel displays to computer modules.
Why do we need a new interface?
Previous attempts to create a standard failed. There are several reasons: to complex / unclear, not flexible or open enough or just not independent from companies (like JILI / JUMPtec).
Why is a cross-company standard needed?
Will this push the customers into the hands of competitors?
No, not at all:
A better exchangeability of modules - which often failed when it came to display Interfaces - will bring more customers to use COMs instead of own CPU designs.
What is new/different with EPI?
There's no hardware change. The widely used panel interfaces (LVDS, TTL, TMDS) are fixed in a clearly defined common scheme.
The software part of EPI is based on the VESA EDID 1.3 definition. The few additional parameters remain EDID conform.
And: EPI is from a technical and a marketing point of view totaly independent from brand names and other brand matters.
Why are additional parameters necessary?
EDID assumes a high level interface which is not directly conneted to a LCD module. Parameters such as pixel per clock or different data mappings are not defined here.
What is needed for EPI?
The most simple case requires 10 signal lines and two additional if the EDID data should be stored with the display unit for autodetect. Using congatec embedded computer modules it's possible to store the EDID data within the BIOS. This makes sense when the replacement of the display is very improbable.
Who joins EPI?
On one hand chip, BIOS and board manufacturers which want to support EPI. Intel for example holds out the prospect to support EPI with the integrated graphic controllers.
On the other hand can all customers and users of embedded PC support the EPI activities. Every active interest leads to more products. Improvements and enhancements are always very welcome.
used abbreviations
LVDS: Low Voltage Differential Signaling
TMDS: Transition Minimized Differential Signaling
VESA: Video Electronics Standards Association
EDID: Extended Display Identification Standard