Kontron KTA55-pITX - Manual (Page 8)

KTD-S0043-A Page 5 Graphics Interface
KTA55/pITX Software Guide
4 Graphics Interface
4.1 LCD/LVDS Technology Overview
4.1.1 Detailed Timing Descriptor (EDID or DisplayID TM )
The input fields Pixel Clock, Horizontal Active, Horizontal Blank, Horizontal Sync Offset, Horizontal Sync
Width, Vertical Active, Vertical Blank, Vertical Sync Offset and Vertical Sync Width must be filled in with the
correct values according to the panels data sheet. In many cases the value for Horizontal/Vertical Blank
cannot be read directly from the data sheet. Instead terms such as Display Period (active pixels/lines) or
Horizontal/Vertical Total appear.
In this case the following calculation can be made:
⇒ Blank Value = Total Value – Active Value.
Sometimes the datasheet does not specify Sync Offset and/or Sync Width. In this case the permissible
values can only be determined though testing. However the rule is:
⇒ The sum of Sync Offset and Sync Width must not exceed the value for Horizontal/Vertical Blank.
Also datasheets are often different for displays with double pixel clock. If Pixel Clock and Horizontal Values
seem to be halved this must be corrected for input:
⇒ The values must always be entered as though it were a panel with single pixel clock.
Example 1:
PRIMEVIEW PM070WL4 (single pixel clock)
Data sheet specifications:
Clock Frequency [typ.] 32 MHz
HSync Period [typ.] 1056 Clocks (equivalent to Horizontal Total)
HSync Display Period [typ.] 800 Clocks (equivalent to Horizontal Active)
HSync Pulse Width [typ.] 128 Clocks
HSync Front Porch [typ.] 42 Clocks
HSync Back Porch [typ.] 86 Clocks
VSync Period [typ.] 525 Lines (equivalent to Vertical Total)
VSync Display Period 480 Lines (equivalent to Vertical Active)
VSync Pulse Width [typ.] 2 Lines
VSync Front Porch [typ.] 10 Lines
VSync Back Porch [typ.] 33 Lines
Result:
Pixel
Clock 32
Horizontal Active 800
Horizontal Blank 256 ((128 + 42 + 86) → H. Pulse Width + H. Front Porch + H.
Back Porch)
Horizontal Sync Offset 42 (H. Front Porch)
Horizontal Sync Width 128 (H. Pulse Width)
Vertical Active 480
Vertical Blank 45 ((2 + 10 + 33) → V. Pulse Width + V. Front Porch + V. Back
Porch)
Vertical Sync Offset 10 (V. Front Porch)
Vertical Sync Width 3 (V. Pulse Width)