openldi

OpenLDI Specification v0.95 © 1999 National Semiconductor Open LVDS Display Interface (OpenLDI) Specification v0.95 May 13, 1999 This is a draft standard and is subject to change. Implementations built to this draft standard may not be compliant with the standard when it is finally published. OpenLDI Specification v0.95 © 1999 National Semiconductor Page i Foreword The OpenLDI specification was developed through the cooperation of companies in the semiconductor, display, computer system, connector, and cable industries to be an open standard for the digital connection of display sources and display devices. This standard is an evolution of the de facto industry standard for the connection of display controllers to LCD panels in notebook computers. The OpenLDI standard draws upon the work of other standards that are widely used, specifically the Video Electronics Standards Association (VESA) and the American National Standards Institute (ANSI). This standard provides a completely digital, plug and play, interface to provide the sharpest, clearest video image obtainable on a digital display device. This standard was developed such that there is no material in this standard for which licensing fees must be paid nor for which membership in a particular organization is required (with the concomitant required sharing of intellectual property) in order to implement this standard. OpenLDI Specification v0.95 © 1999 National Semiconductor Page ii Table of Contents 1 Scope..................................................................................................................................1 2 Purpose...............................................................................................................................1 3 References and Definitions..................................................................................................1 3.1 Normative References.....................................................................................................1 3.2 Definitions......................................................................................................................2 3.3 Language Conventions....................................................................................................2 3.4 Ordering Conventions.....................................................................................................2 4 Overview............................................................................................................................3 5 Logical Interface.................................................................................................................4 5.1 Overview.........................................................................................................................4 5.1.1 Security of Data Transmitted via OpenLDI..............................................................6 5.2 Operation of OpenLDI.....................................................................................................6 5.2.1 Default Configuration of OpenLDI..........................................................................6 5.2.1.1Default Configuration for a Display Source.........................................................6 5.2.1.2Default Configuration for a Display Device.........................................................6 5.2.2 Plug and Play Operation of OpenLDI ......................................................................7 5.2.2.1Display Device Attach Event...............................................................................7 5.2.2.2Display Device Removal Event............................................................................7 5.2.2.3Display Source Attach Event...............................................................................7 5.2.2.4Display Source Removal Event............................................................................7 5.2.3 DDC........................................................................................................................7 5.2.4 EDID.......................................................................................................................7 5.2.5 Gamma Correction..................................................................................................8 5.2.5.1Display Source Gamma Correction......................................................................8 5.2.5.2Display Device Gamma Correction......................................................................8 5.3 Pixel Formats..................................................................................................................8 5.3.1 18-bit Single Pixel Format.......................................................................................9 5.3.2 24-bit Single Pixel Format.......................................................................................9 5.3.3 18-bit Dual Pixel Format.........................................................................................9 5.3.4 24-bit Dual Pixel Format.........................................................................................9 5.4 Serialization....................................................................................................................9 5.4.1 Mapping Pixel Bit Numbers Onto Interface Bit Numbers.......................................10 5.4.2 Unbalanced Operating Modes................................................................................10 5.4.2.118-bit Single Pixel Mode, Unbalanced...............................................................11 5.4.2.224-bit Single Pixel Mode, Unbalanced...............................................................12 5.4.2.318-bit Dual Pixel Mode, Unbalanced..................................................................13 5.4.2.424-bit Dual Pixel Mode, Unbalanced..................................................................14 5.4.3 Balanced Operating Modes....................................................................................14 5.4.3.118-bit Single Pixel Mode, Balanced...................................................................16 5.4.3.224-bit Single Pixel Mode, Balanced...................................................................17 5.4.3.318-bit Dual Pixel Mode, Balanced......................................................................18 5.4.3.424-bit Dual Pixel Mode, Balanced......................................................................19 6 Electrical Interface............................................................................................................20 OpenLDI Specification v0.95 © 1999 National SemiconductorPage iii 6.1 Overview.......................................................................................................................20 6.2 LVDS Interface.............................................................................................................20 6.2.1 ANSI/EIA/TIA-644...............................................................................................20 6.2.1.1Bit Times...........................................................................................................20 6.2.2 Additional Pre-emphasis........................................................................................20 6.2.3 Intra-pair Skew Tolerance......................................................................................21 6.2.4 Inter-pair Skew Tolerance......................................................................................21 6.3 USB Interface................................................................................................................22 6.4 DDC Interface...............................................................................................................22 7 Mechanical Interface.........................................................................................................23 7.1 Overview.......................................................................................................................23 7.2 OpenLDI Connector......................................................................................................23 7.2.1 Pin Assignment – Shielded Twisted Pair................................................................24 7.2.2 Pin Assignment – Unshielded Twisted Pair............................................................24 7.2.3 Mechanical Drawings............................................................................................25 7.2.4 Connector Retention..............................................................................................27 7.2.5 Contact Finish........................................................................................................27 7.2.6 Shell Finish............................................................................................................27 7.3 OpenLDI Cabling..........................................................................................................27 7.3.1 Cable Length.........................................................................................................27 7.3.2 Number of Signal Conductors................................................................................27 7.3.3 Wire Gauge...........................................................................................................27 7.3.4 Conductor Resistance............................................................................................27 7.3.5 Insulation...............................................................................................................27 7.3.6 Shield Requirement...............................................................................................28 7.3.7 Single Twisted Pair Transmission Skew (Intra-pair Skew).....................................28 7.3.8 Multiple Twisted Pair Transmission Skew (Inter-pair Skew)..................................28 7.3.9 USB Cable Requirements......................................................................................28 7.3.10DDC Cable Requirements......................................................................................28 8 Testing Requirements........................................................................................................29 8.1 Environmental Requirements.........................................................................................29 8.1.1 Temperature Life...................................................................................................29 8.1.2 Cyclic Humidity....................................................................................................29 8.1.3 Thermal Shock......................................................................................................29 8.1.4 Corrosion Resistance.............................................................................................29 8.2 Electrical Requirements.................................................................................................29 8.2.1 Dielectric Withstanding Voltage............................................................................29 8.2.2 Insulation Resistance.............................................................................................29 8.2.3 Contact Resistance.................................................................................................30 8.2.4 Shell to Shell and Shell to Bulkhead Resistance.....................................................30 8.2.5 Impedance of Digital Signal Lines.........................................................................30 8.2.6 Impedance of LVDS and USB Differential Signal Lines........................................30 8.2.7 Contact Current Rating..........................................................................................30 8.2.8 Bandwidth of Digital Signal Lines.........................................................................30 8.2.9 Bandwidth of LVDS and USB Differential Signal Lines........................................30 8.2.10Crosstalk of LVDS and USB Differential Signal Lines..........................................30 OpenLDI Specification v0.95 © 1999 National SemiconductorPage iv 8.3 Mechanical Requirements.............................................................................................30 8.3.1 Durability..............................................................................................................30 8.3.2 Mating and Unmating Force..................................................................................31 8.3.3 Mechanical Shock..................................................................................................31 8.3.4 Vibration...............................................................................................................31 9 Conformance Statement Proforma.....................................................................................32 9.1 Introduction...................................................................................................................32 9.2 Abbreviations and Special Symbols...............................................................................32 9.2.1 Status Symbols......................................................................................................32 9.2.2 General Abbreviations...........................................................................................32 9.3 Instructions for Completing the Conformance Statement Proforma................................33 9.3.1 General Structure of the Conformance Statement Proforma...................................33 9.3.2 Additional Information..........................................................................................33 9.3.3 Exception Information...........................................................................................34 9.3.4 Conditional Status.................................................................................................34 9.4 Conformance Statement Proforma—OpenLDI..............................................................35 9.4.1 Implementation Identification................................................................................35 9.4.2 Conformance Summary, OpenLDI.........................................................................35 9.4.3 IUT Configuration.................................................................................................36 OpenLDI Specification v0.95 © 1999 National Semiconductor Page v Table of Figures Figure 5-1, OpenLDI Architecture..............................................................................................5 Figure 5-2, 18-bit Single Pixel Transmission, Unbalanced........................................................11 Figure 5-3, 24-bit Single Pixel Transmission, Unbalanced........................................................12 Figure 5-4, 18-bit Dual Pixel Transmission, Unbalanced...........................................................13 Figure 5-5, 24-bit Dual Pixel Transmission, Unbalanced...........................................................14 Figure 5-6, 18-bit Single Pixel Transmission, Balanced............................................................16 Figure 5-7, 24-bit Single Pixel Transmission, Balanced............................................................17 Figure 5-8, 18-bit Dual Pixel Transmission, Balanced...............................................................18 Figure 5-9, 24-bit Dual Pixel Transmission, Balanced...............................................................19 Figure 6-1, Pre-emphasis Template...........................................................................................21 Figure 7-1, Pin Assignment for Shielded Twisted Pair Cabling.................................................24 Figure 7-2, Pin Assignment for Unshielded Twisted Pair Cabling.............................................25 Figure 7-3, Example OpenLDI 36 Position Receptacle Mechanical Drawing............................26 Figure 7-4, Example Panel Cutout for OpenLDI 36 Position Receptacle...................................26 Figure 7-5, Example OpenLDI 36 Position Plug (TBD)............................................................27 OpenLDI Specification v0.95 © 1999 National SemiconductorPage vi Table of Tables Table 5-1, Common Display Resolutions....................................................................................9 Table 5-2, Bit Number Mappings..............................................................................................10 Table 5-3, Control Transmission in 18-bit Balanced Single Pixel Mode....................................16 Table 5-4, Control Transmission in 24-bit Balanced Single Pixel Mode....................................17 Table 5-5, Control Transmission in 18-bit Balanced Dual Pixel Mode......................................18 Table 5-6, Control Transmission in 24-bit Balanced Dual Pixel Mode......................................19 Table 7-1, Part Numbers for OpenLDI Connector Receptacles..................................................23 Table 7-3, Part Numbers for OpenLDI Connector Receptacles..................................................23 OpenLDI Specification v0.95 © 1999 National Semiconductor Page 1 1 Scope The OpenLDI specification describes a logical, electrical, and mechanical interface between a display source and a display device for the transfer of digital display data. Included in this interface are communication channels for display identification (DDC/CI and EDID) and connection of peripheral devices (USB). Use of this interface is appropriate for both direct attachment of a display source to a display device in a single assembly, e.g. notebook computers and single cabinet HDTVs, as well as for attachment of a display source to a remote display device, e.g., standalone LCD computer monitors. OpenLDI is an evolutionary development of the de facto industry standard for the interconnection of video controllers to LCD panels in notebook computers. 2 Purpose The purpose of the OpenLDI specification is to provide for the transfer of digital display data between a display source and a display device, avoiding the conversion of the display data into analog form with its resultant loss of information. Additionally, this specification describes a signaling mechanism that minimizes the number of wires that must be used to connect the display source and display device, as well as minimizes electromagnetic emissions. The interface described provides the flexibility to support a wide range of display formats, refresh rates, and pixel depths. 3 References and Definitions 3.1 Normative References The following standards are referenced in this specification and their provisions are incorporated where they are cited. The versions listed are current at the time of publication of this specification. VESA1 Display Data Channel Command Interface (DDC/CI) Standard, Version 1, August 14, 1998. VESA Extended Display Identification Data (EDID) Standard, Version 3, November 13, 1997. Universal Serial Bus Specification, Version 1.0, January 15, 1996. ANSI/TIA/EIA-644-1995 Electrical Characteristics of Low Voltage Differential Signaling (LVDS) Interface Circuits, November 1995. ANSI/EIA 364-C-1994 Electric Connector Test Procedure 1 VESA is a registered trademark of the Video Electronics Standards Association. OpenLDI Specification v0.95 © 1999 National Semiconductor Page 2 3.2 Definitions LVDS Low Voltage Differential Signaling (ANSI Standard 644) LDI LVDS Display Interface DDC Display Data Channel EDID Extended Display Identification Data USB Universal Serial Bus 3.3 Language Conventions T