NEC LCD52V User Guide

DDc/ci & NaviSet

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Introduction

The majority of hardware connected to Windows-based PC systems does not require a large amount of user

configuration after its initial installation. Display monitors, however, are the notable exception. Today’s displays

offer users vast control over their configuration, but this is often through cryptic front-panel controls with

non-standard interfaces, minimal or no localization and minimal assistance to the user.

Consequently, user frustration with display configuration is high, and often display configuration is not optimal.

The set of controls available to the user varies among manufacturers, and even among display models from the

same manufacturer. Often, modifying a setting causes changes in other settings, requiring the user to move

back and forth among several controls to find the right balance.

In attempting to address these issues, vendors have used various methods to allow the operating system to

control the display settings. These controls have taken various forms, but most have several drawbacks,

including:

· Incons

Incons

Inconsis

isttttteeeeent Int

nt Int

nt Inteeeeerrrrrface

face

facesssss..... The method of connecting the display to the PC for control either requires

additional connections to the display beyond the data connection or requires non-standard signaling over

the data connection. The former results in increased manufacturing costs; the latter may mean that the

display can work only with specific display adapters.

· Incons

Incons

Inconsis

isttttteeeeent UIs

nt UIs

nt UIs..... The interfaces often do not follow Windows user interface (UI) guidelines, and may have the

same drawbacks as the built-in display controls: cryptic controls, lack of localization and interdependent

controls.

Both cases can result in increased user confusion and support calls.

Standardization in the control of display configuration provides all-around gains. User confusion and therefore

support calls are lessened, and system integration improved. Manufacturing costs of displays are improved as well.

DDC/CI as an Enabling Technology

Windows operating systems use VESA Display Data Channel (DDC) protocols to retrieve Extended Display

Identification Data (EDID) data from displays through the display adapter driver, which reports the display as a

child device.

The solution to the above problems is for Windows and the display hardware to fully implement VESA DDC Command

Interface (DDC/CI) bi-directional control and to create a Windows-based control panel for the display hardware.

In addition to the inter-integrated circuit (I

C) interface for the display itself, many display adapters contain an

interface for other on-board devices such as TV tuners or video capture devices. The I

C bus is a standard

protocol two-wire (clock and data) serial data bus that is bi-

directional, but most display adapter drivers only expose the

C interface to the non-display devices for Windows Driver

Model (WDM) child drivers to use.

Simple changes to what is exposed on the I

C interface and to

display adapter drivers allow WDM child display drivers to

control displays by way of the DDC/CI standard. The display

child driver can in turn be controlled by a standard display control panel extension.

DDC/CI Advantages

DDC/CI enables two-way communication between monitors and their video adapters, which provides many

advantages. Today’s monitors do more than merely display text; the best possible display configuration is

mission-critical for applications including digital imaging, pre-press, graphic arts and video production. On-

screen colors that don’t match printed output or are off because of an incorrect setting waste valuable time

“Standardization in the control

of display configuration

provides all-around gains.”