DDC/CI标准：I2C协议驱动的显示器与设备交互指南

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DDC/CI标准，全称为Display Data Channel Command Interface Standard（显示数据通道命令接口标准），是由Video Electronics Standards Association (VESA)制定的一项通信协议。它旨在通过Display Data Channel (DDC)提供双向交互式控制，以满足用户对即插即用功能的需求。这个标准定义了一种基于I2C（Inter-Integrated Circuit）的通信协议，适用于各类显示设备，包括CRT（阴极射线管）、LCD（液晶显示器）和PDP（等离子显示屏），以及不同的视频接口，如VGA、DVI和HDMI。 DDC/CI（以前称为DDC2Bi）的核心作用是作为主机与显示器之间的桥梁，允许数据在两者之间高效传输，无论是查询屏幕信息还是发送控制指令。这个标准的初衷是为了简化接口，使得设备间的兼容性增强，无需过多依赖特定的技术细节，从而降低系统复杂性和成本。在VESA 1.1版本的《DDC/CI标准》中，其主要内容可能包括以下几点： 1. **标准架构**：明确了协议的工作原理和实现方式，强调了其I2C基础，这有助于确保不同制造商能够遵循统一的通信规则。 2. **功能划分**：根据用户需求的不同层次，定义了E-DDC的不同通信级别，这些级别可能涉及数据报告速率、控制指令的复杂度和响应时间等方面。 3. **兼容性**：强调了DDC/CI标准与各种显示技术的兼容性，使其能够在多种显示设备上通用，提升了市场的接受度。 4. **扩展性**：这一修订版的目的是扩展E-DDC标准，可能包含了新的功能特性、错误处理机制或者性能提升，以适应不断发展的技术趋势。 5. **接口规范**：详述了接口的具体接口规范，包括信号时序、数据格式、错误检测和校验等，以保证数据传输的可靠性和效率。 6. **应用示例**：可能提供了示例代码或操作指南，帮助开发者理解和实现DDC/CI协议在实际产品中的应用。 7. **版权和许可**：明确了版权信息和使用条款，保护了VESA的权利同时也鼓励了标准的采用和创新。 8. **版本更新**：注明了发布日期，表明这是VESA对于DDC/CI标准的最新修订，反映了当时的技术水平和市场需要。 DDC/CI标准是一个关键的IT行业规范，它促进了显示器与主机之间的标准化交互，推动了电子产品的易用性和兼容性，对于现代显示设备的发展和市场整合起到了重要作用。

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VESA DDC/CI Standard Page 8 of 42

Table 1 : DDC Modes......................................................................................................................9

Table 2 - Reference Documents.....................................................................................................11

Table 3 - I

C Notation....................................................................................................................12

Table 4 : Examples of External Display Dependent Devices........................................................15

Table 5 : Examples of Fixed I

C Address devices.........................................................................16

Table 6 : I

C Bus Notation.............................................................................................................17

Table 7 : Capability String Fields..................................................................................................30

Table 8 - FAQ................................................................................................................................41

Figure 1: Key Elements of a DDC/CI System...............................................................................13

Figure 2 - Recommended SCL and SDA Line Terminations........................................................37

VESA DDC/CI Standard Page 9 of 42

1. OVERVIEW

1.1 Summary

This standard defines a bidirectional communications channel between a host device and a display using the

Display Data Channel (defined in the VESA E-DDC standard) as the physical layer. Implementation allows

interaction beteen the host and display devices.

The main changes in this revision are the provision of support for the ‘table class’ of VCP codes introduced in the

MCCS standard version 2 and to restructure and expand the explanations of command structures. Minor changes

included elimination of the references to unused standards and other points to improve clarity.

1.2 Background

Table 1 summarizes the various DDC modes (old and current), the purpose of each and current status. Some

modes and terms are no longer recommended. The fields with a gray background show older standards or

terminology that is not recommended. … note that all new designs are recommended to support E-DDC

addressing and those requiring support for the MCCS VCP codes are recommended to also support DDC/CI.

Name Purpose Comment

DDC1

Original uni-directional mode (display → host)

Not recommended for new designs

DDC2 Original bi-directional mode. Host able to request EDID

data

Not recommended for new designs

DDC2B A generic term for all bi-directional DDC modes Not recommended terminology

DDC2Bi Original name for command interface mode Old terminology, replaced by DDC/CI

E-DDC Enhanced DDC, a bi-directional mode, supporting access to

EDID data including all possible EDID extension blocks

Recommended for all new display

designs

Note: This is base level of support

recommended for all new display

designs. Some designs will choose to

implement DDC/CI to provide

additional functions.

DDC/CI The command interface uses I

C single master

communications and allows MCCS VCP codes and

associated data to be sent to or received from a display

Recommended for new display designs

when support for the MCCS VCP

codes is required.

Note: This does not replace the need

for E-DDC support, DDC/CI

complements E-DDC.

Table 1 : DDC Modes

1.3 VCP Codes

Commands used over the DDC/CI channel are known as VCP Codes (Virtual Control Panel) – see the VESA

MCCS standard for details. (Complete reference to MCCS in “Table 2 - Reference Documents”.)

Version 2 of MCCS provides a much more complete set of VCP codes with particular emphasis on the needs of

new (e.g. LCD, PDP) technologies.

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DDC/CI标准：I2C协议驱动的显示器与设备交互指南

VESA DDC协议标准（Display Data Channel Command Interface standard） 包括应用实例及代码

DDCCI 命令说明

带有CI-V端口的Icom无线电上的外部S-Meter-项目开发

S5和S6建立ibgp协议号为100，且S5和S6还有S7用rip协议互联， R1和R2建立ibgp协议号为200，且R1和R2与R3用ospf协议互联，

stm32 si24r1程序

解释这段matlab代码r1 = sqrt(r1vec*r1vec.')

MAOPAO: MOV R0,#09H LOOP1: MOV R1,#30H MOV A,R0 MOV R2,A LOOP2: MOV A,@ R1 MOV R3,A INC R1; SUBB A,@R1 ; JC LOOP3 ; MOV A,R3 XCH A,@R1 DEC R1 MOV @ R1,A INC R1 LOOP3: DJNZ R2,LOOP2 DJNZ R0,LOOP1 SJMP $ END 翻译这段代码

读懂下面程序，写出程序执行的过程 backwordSUBR1,R1,#1 CMPR1，＃0;比较R1和0 BEQ forward ;如果R1==0,跳转到forward处执行 SUBR1,R2,#3 SUBR1,R1,#1 forwardADDR1,R2,#4 ADDR2,R3，#2 B backword

R2的值是0x87，分别LSR R1,R2,#2和ASR R1,R2,#2后，R1的值分别是

逐行解释代码LDR R1,[R0];MVN R1,R1;STR R1,[R0]

已知R0=1,R1=2,R2=3,R3=4,R5=0,则执行下列指令后：ADD R0,R2,R3 AND R4,R1,R0 SUB R1,R3,R5 EOR R5,R1,R4 R1等于多少，R5等于多少

[R1]ospf 1 [R1-ospf-1] [R1-ospf-1]import-toute rip 1 ^ Error: Unrecognized command found at '^' position. [R1-ospf-1] [R1-ospf-1]rip 1 [R1-rip-1] [R1-rip-1]import-rpute ospf 1 ^ Error: Unrecognized command found at '^' position. [R1-rip-1]

已知R0=1,R1=2,R2=3,R3=4,则执行下列指令后：ADD R0,R2,R3 AND R4,R1,R0 SUB R1,R3,R5 EOR R5,R1,R4,R1等于多少，R5等于多少

已知R0=1,R1=2,R2=3,R3=4,则执行下列指令后：ADD R0,R2,R3 AND R4,R1,R0 SUB R1,R3,R5 EOR R5,R1,R4 R1等于多少，R5等于多少

优化以下代码 AREA TEST, CODE, READONLY ENTRY MOV R0, #0 ; MOV R1, #1 ;loop ADD R0, R0, R1 ; ADD R1, R1, #1 ; TEQ R1, #N+1 ; ; ; BNE loop ; END ;

假设（R1）=01H，（R2）=02H，在所给定的运算器数据通路中，怎样实现（R1）+(R2)→R1？（即R1寄存器与R2寄存器内容相加，结果送R1）

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VESA DDC协议标准（Display Data Channel Command Interface standard）包括应用实例及代码