82845G Datasheet, PDF (131/193 Pages) Intel Corporation – Intel 82845G/82845GL/82845GV Graphics and Memory Controller Hub (GMCH)

Functional Description
4.5
Display Interfaces
The GMCH has three display ports, one analog and two digital. Each port can transmit data
according to one or more protocols. The digital ports are connected to an external device that
converts one protocol to another. Examples of this are TV encoders, external DACs, LVDS
transmitters, and TMDS transmitters. Each display port has control signals that may be used to
control, configure, and/or determine the capabilities of an external device.
The GMCH has one dedicated display port, the analog port. DVO ports B and C are multiplexed
with the AGP interface. When a system utilizes an AGP connector, DVO ports B and C can be
utilized via an ADD (AGP Digital Display) card. Ports B and C can also operate in dual channel
mode, where the data bus is connected to both display ports, allowing a single device to take data at
twice the pixel rate.
The GMCH’s analog port uses an integrated 350 MHz RAMDAC that can directly drive a standard
progressive scan analog monitor up to a resolution of 2048x1536 pixels with 32-bit color at 60 Hz.
The GMCH’s DVO ports are each capable of driving a 165 MHz pixel clock. Each port is capable
of driving a digital display up to 1600x1200 at 60 Hz. When in dual-channel mode, the GMCH can
drive a flat panel up to 2048x1536 at 60 Hz or dCRT/HDTV up to 1920x1080 at 85 Hz.
The GMCH is compliant with Digital Visual Interface (DVI) Specification, Revision 1.0. When
combined with a DVI compliant external device and connector, the GMCH has a high-speed
interface to a digital display (e.g., flat panel or digital CRT).
Table 4-9. Display Port Characteristics
Interface Protocol
Analog
Digital Port B
Digital Port C
HSYNC
VSYNC
BLANK
STALL
Field
Display_Enable
Image Aspect Ratio
Pixel Aspect Ratio
Voltage
Clock
Max Rate
Format
Control Bus
External Device
Connector
Special Functions
RGB DAC
Intel^® DVO 2.0
DVO 2.0
Yes Enable/Polarity
Yes Enable/Polarity
No
Yes⁽¹⁾
Yes⁽¹⁾
No
Yes
Yes
No
Yes
No
Yes
Yes⁽¹⁾
Programmable and typically 1.33:1 or 1.78:1
Square⁽¹⁾
RGB 0.7 V p-p
1.5 V
1.5 V
NA
Differential
350 Mpixel
165/330 Mpixel
Analog RGB
RGB 8:8:8 YUV 4:4:4
DDC1/DDC2B
DDC2B
No
TMDS/LVDS Transmitter /TV Encoder
VGA/DVI-I
DVI/CVBS/S-Video/Component/SCART
Monitor Sense
Dual Channel Mode
NOTE:
1. Single signal software selectable between display enable and Blank#.
Intel^® 82845G/82845GL/82845GV GMCH Datasheet
131