User's Manual

Intel® 815 Chipset: Graphics Controller PRM, Rev 1.0

3.3.1. VGA and Extended VGA I/O and Memory Register Map

Table 3. I/O and Memory Register Map

Address Register Name (Read) Register Name (Write)

2D Registers

3B0h–3B3h Reserved Reserved

3B4h VGA CRTC Index (CRX) (monochome) VGA CRTC Index (CRX) (monochome)

3B5h VGA CRTC Data (monochome) VGA CRTC Data (monochome)

3B6h–3B9h Reserved Reserved

3BAh VGA Status Register (ST01) VGA Feature Control Register (FCR)

3BBh–3BFh Reserved Reserved

3C0h VGA Attribute Controller Index (ARX) VGA Attribute Controller Index (ARX)/

VGA Attribute Controller Data (alternating

writes select ARX or write ARxx Data)

3C1h VGA Attribute Controller Data

(read ARxx data)

Reserved

3C2h VGA Feature Read Register (ST00) VGA Miscellaneous Output Register (MSR)

3C3h Reserved Reserved

3C4h VGA Sequencer Index (SRX) VGA Sequencer Index (SRX)

3C5h VGA Sequencer Data (SRxx) VGA Sequencer Data (SRxx)

3C6h VGA Color Palette Mask (DACMASK) VGA Color Palette Mask (DACMASK)

3C7h VGA Color Palette State (DACSTATE) VGA Color Palette Read Mode Index (DACRX)

3C8h VGA Color Palette Write Mode Index

(DACWX)

VGA Color Palette Write Mode Index

(DACWX)

3C9h VGA Color Palette Data (DACDATA) VGA Color Palette Data (DACDATA)

3CAh VGA Feature Control Register (FCR) Reserved

3CBh Reserved Reserved

3CCh VGA Miscellaneous Output Register (MSR) Reserved

3CDh Reserved Reserved

3CEh VGA Graphics Controller Index (GRX) VGA Graphics Controller Index (GRX)

3CFh VGA Graphics Controller Data (GRxx) VGA Graphics Controller Data (GRxx)

3D0h–3D1h Reserved Reserved

2D Registers

3D4h VGA CRTC Index (CRX) VGA CRTC Index (CRX)

3D5h VGA CRTC Data (CRxx) VGA CRTC Data (CRxx)

2D Registers

3D8h–3D9h Reserved Reserved

3DAh VGA Status Register (ST01) VGA Feature Control Register (FCR)

3DBh–3DFh Reserved Reserved