EDID技术介绍.doc

EDID技术介绍1 介绍：DDC 是显示器与电脑主机进行通信的一个总线标准，其全称是：DISPLAY DATA CHNNEL。它的基本功能就是将显示器的电子档案资料信息，诸如可接收行场频范围、生产厂商、生产日期、产品序列号、产品型号、标准显示模式及其参数、 所支持的DDC标准类别、EDID的版本信息等等。高版本的DDC标准总线还可以允许电脑主机直接调节显示器的基本参数，诸如亮度、对比度、行场幅度的大 小、行场中心位置、色温参数等等。2 DDC总线标准类别：1）DDC1：单向传输，CLOCKED BY VSYNC，只传输128 BYTE EDID标准数据信息。2） DDC2B：单向传输（地址为：0xA0/A1），是一个简单的从存储器读取数据信息的标准I2C协议，其方向为从显示器到电脑主机。3） DDC2Bi：双向传输，I2C SLAVE MODE，传送图形信息（地址为：0x6E/6F，0x50/51）, 支持简单的ACCESS.BUS总线标准。4） DDC2B+：双向传输，点对点，不支持ACCESS.BUS，传输EDID/VDIF标准数据信息（地址为：0x6E/6F，0x50/51）。5） DDC2AB：双向传输，支持ACCESS.BUS，传输EDID/VDIF标准数据信息（地址为：0x6E/6F，0x50/51）。6）3 EDID数据标准：EDID(Extended Display Identification Data Standard) 就是显示器通过DDC传输给电脑主机的标准数据信息，至今已发布到第三版本，即EDID Version3，前面分别有EDID Version 1.0，Revision 0，EDID Version 1，Revision 1，EDID Version 2，Revision 0，EDID Version 2，Revision 1等版本。就数据信息量而分，EDID分为128 BYTE和256 BYTE，将来也许会有更多数据信息量的新版EDID公布EDID(Extended Display Identification Data Standard) 就是显示器通过DDC传输给电脑主机的标准数据信息。EDID分为128 BYTE和256 BYTEEDID数据格式：0007: Header information0817: Complete serial number0809: Manufacturer ID1011: Product ID Code (little-endian)1215: Serial Number (little-endian)16: Week of Manufacture17: Year of Manufacture. Add 1990 to the value for actual year.18: EDID Version Number19: EDID Revision Number20-24: Basic Display Parameters20: VIDEO INPUT DEFINITIONbit 7: 0=analog, 1=digitalif bit 7 is digital: bit 0: 1=DFP 1.x compatibleif bit 7 is analog:bit 6-5: video level 00=0.7, 0.3,01=0.714, 0.286, 10=1, .4 11=0.7, 0bit 4: blank-to-black setupbit 3: separate syncsbit 2: composite syncbit 1: sync on greenbit 0: serration vsync21: Maximum Horizontal Image Size (in centimeters).22: Maximum Vertical Image Size (in centimetres).23: Display Gamma. Divide by 100, then add 1 for actual value.24: Power Management and Supported Feature(s):bit 7: standby bit 6: suspendbit 5: active-off/low powerbit 4-3: display type.00=monochrome, 01=RGB colour,10=non RGB multicolour, 11=undefinedbit 2: standard colour spacebit 1: preferred timing modebit 0: default GTF supported25-34: CHROMA INFO 25: low significant bits for Red X (bit 7-6), Red Y (bit 5-4), Green X (bit 3-2), Green Y (bit 1-0).26: low significant bits for Blue X (bit 7-6), Blue Y (bit 5-4), White X (bit 3-2), White Y (bit 1-0).2734: high significantbits for Red X, Red Y, Green X, Green Y, Blue X, Blue Y, White X, White Y. To decode actual value, rearrange bits as follows:High significant bits 7-0 for (channel), low significant bits for (channel).Actual value is between 0.000 and 0.999, but encoded value is between 000h and 3FFh.35: ESTABLISHED TIMING Ibit 7-0: 72040070 Hz, 72040088 Hz, 64048060 Hz, 64048067 Hz,64048072 Hz, 64048075 Hz, 80060056 Hz, 80060060 Hz36: ESTABLISHED TIMING IIbit 7-0: 80060072 Hz, 80060075 Hz, 83262475 Hz, 102476887 Hz (Interlaced),102476860 Hz, 102476870 Hz, 102476875 Hz, 1280102475 Hz37: Manufacturers Reserved Timing3853: Standard Timing Identification.2 bytes for each record.First byte Horizontal resolution.Multiply by 8, then add 248 for actual value.Second byte bit7-6: Aspect ratio.Actual vertical resolution depends on horizontal resolution.00=16:10, 01=4:3, 10=5:4, 11=16:9bit 5-0: Vertical frequency.Adds 60 to get actual value.5471: Desc riptor Block 15455: Pixel Clock (in 10 kHz) or 0 If Pixel Clock is non null:56: Horizontal Active (in pixels)57: Horizontal Blanking (in pixels)58: Horizontal Active high (4 upper bits)Horizontal Blanking high (4 lower bits)59: Vertical Active (in pixels)60: Vertical Blanking (in vertical pixels/lines)61: high significant bits for Vertical Active (4 upper bits) high significantbits for Vertical Blanking (4 lower bits)62: Horizontal Sync Offset (in pixels)63: Horizontal Sync Pulse Width (in pixels)64: Vertical Sync Offset (in lines)(4 upper bits) Vertical Sync Pulse Width (in lines)4 lower bits)65: high significant bits for Horizontal Sync Offset(bit 7-6)high significant bits for Horizontal Sync Pulse Width (bit 5-4)high significant bits for Vertical Sync Offset (bit 3-2)high significant bits for Vertical Sync Pulse Width (bit 1-0)66: Horizontal Image Size (in mm)67: Vertical Image Size (in mm)68: high significant bits for HorizontalImage Size (4 upper bits)high significant bits for Vertical Image Size (4 lower bits)69: Horizontal Border70: Vertical Border71: Interlaced or not (bit 7)Stereo or not (bit 6-5) (00 means not)Separate Sync or not (bit 4-3)Horizontal Sync positive or not (bit 2)Vertical Sync positive or not (bit 1)Stereo Mode (bit 0) (unused if 6-5 are 00)If Pixel Clock is null:56:057: Block type FFh=Monitor Serial Number, FEh=ASCII string, FDh=Monitor Range Limits, FCh=Monitor name, FBh=Colour Point Data, FAh, Standard Timing Data, F9h=Currently undefined, F8h=defined by manufacturer58: Unknown5971: Desc riptor block contents.If block type is FFh, FEh, or FCh, the entire area is a text string.If block type is FDh:5963: Min Vertical frequency, Max Vertical frequency, Min Horizontal frequency (in kHz), Max Horizontal frequency (in kHz), pixel clock (in MHz (multiply by 10 for actual value)6465: Secondary GTF toggle If encoded value is 000A, bytes 59-63 are used. If encoded value is 0200, bytes6771 are used.66: Start horizontal frequency (in kHz). Multiply by 2 for actual value.67: C. Divide by 2 for actual value.68-69: M (little endian).70: K 71: J. Divide by 2 for actual value. If block type is FBh:59: W Index 0. If set to 0, bytes60-63 are not used. If set to 1,6163 are assigned to white point index #164: W Index 1. If set to 0, bytes65-68 are not used. If set to 2,6568 are