VESA Digital Flat Panel explained

DFP
Type:Digital video connector
Designer:Video Electronics Standards Association
Design Date:February 14, 1999
Superseded:VGA connector
Superseded By:Digital Visual Interface
Data Signal:PanelLink protocol Transition Minimized Differential Signaling
Data Bit Width:3 bits plus clock
Data Devices:1
Data Style:PanelLink (Serial)
Num Pins:20
Pin1 Name:TMDS data 1 +
Pin2 Name:TMDS data 1 –
Pin3 Name:GND
Pin4 Name:GND
Pin5 Name:TMDS data C +
Pin6 Name:TMDS data C –
Pin7 Name:GND
Pin8 Name:+ 5V
Pin9 Name:Reserved
Pin10 Name:Reserved
Pin11 Name:TMDS data 2 +
Pin12 Name:TMDS data 2 –
Pin13 Name:GND
Pin14 Name:GND
Pin15 Name:TMDS data 0 +
Pin16 Name:TMDS data 0 –
Pin17 Name:Reserved
Pin18 Name:Reserved
Pin19 Name:DDC data
Pin20 Name:DDC clock

The VESA Digital Flat Panel (DFP) interface standard specifies a video connector and digital TMDS signaling for flat-panel displays.[1] It features 20 pins and uses the PanelLink protocol; the standard is based on the preceding VESA Plug and Display (P&D) standard, ratified in 1997. Unlike the later, electrically-compatible Digital Visual Interface (DVI, 1999), DFP never achieved widespread implementation.

History

P&D combined analog and digital video with data over USB and FireWire to reduce cable clutter, but the feature creep resulted in an unpopular, expensive connector.[2] Compaq described DFP as a "transition" step between the analog VGA connector and P&D: DFP was designed by a consortium including Compaq, Hewlett-Packard, and ATI Technologies as a smaller, simpler connector, dropping support for analog video and data in favor of transmitting exclusively digital video signals.[1]

The connector was used by displays such as the Compaq Presario FP400, FP500, FP700, Fp720, 5204, and 5280. It was offered on graphics cards such as the Xpert LCD,[3] and Rage LT Pro by ATI Technologies, and the Oxygen GVX1[4] by 3Dlabs.

Design

DFP is compatible electrically with P&D (and by extension, DVI); DFP uses the Display Data Channel (DDC) standard level DDC2B for operation and the Extended Display Identification Data (EDID) protocol to identify the display to the host.[5] Like the preceding P&D, DFP uses the PanelLink TMDS protocol developed by Silicon Image for digital video signals.[2]

The DFP standard specifies a 20-pin mini D ribbon connector;[5] however, as the signal protocols are identical, DFP connectors generally are compatible with devices equipped with a DVI interface by using a passive adaptor.

All DFP-compliant devices are required to support resolutions of 640×400, 720×400, and 640×480 (each at a refresh rate of 60Hz) as a minimum level of interoperability, although the resulting display may not necessarily be centered or scaled.[5]

DFP was superseded by DVI because DFP, like P&D, is limited to a single-link TMDS signal. In contrast, DVI is capable of higher maximum resolutions because it supports a dual-link TMDS signal; in addition, DVI also supports analog video, which makes the VGA connector redundant.[2]

External links

Notes and References

  1. Gary . Manchester . 1999 . https://web.archive.org/web/20160112151649/http://www.tu-chemnitz.de/informatik/RA/news/stack/kompendium/vortraege_99/peripherie/standards/dfp/DFPwhitepap.PDF . The VESA Digital Flat Panel (DFP) Standard: A White Paper . VESA Marketing Committee . January 12, 2016 . dead.
  2. Digital Visual Interface & TMDS Extensions . October 2004 . Silicon Image . 31 January 2023.
  3. Web site: XPERT LCD. dead . https://web.archive.org/web/20030721020756/http://ati.com/products/rageltpro/xpertlcd/index.html . 2003-07-21 .
  4. Web site: Oxygen GVX1 AGP specs sheet.
  5. Web site: VESA Digital Flat Panel (DFP) Standard, Version 1 . February 14, 1999 . Video Electronics Standards Association . https://web.archive.org/web/20010602233109/http://www.vesa.org:80/dfpfinal.pdf . June 2, 2001 . dead.