Intel® 815 Chipset: Graphics Controller PRM, Rev 1.0

R

Bit

 

Descriptions

 

 

23:18

Reserved.

 

 

17

Vertical Blank Enable.

 

0

= Vertical Blank Status Disabled

 

1

= Vertical Blank Status Enabled

 

 

16

Overlay Registers Upated Enable.

 

0

= Overlay Registers have been updated during Vertical Blank Status Disabled

 

1

= Overlay Registers have been updated during Vertical Blank Status Enabled

 

 

15

Flat Panel Hot Plug Detect Status. This bit is the state of the TVCLKIN pin of the TV/Flat Panel

 

interface. This pin signals an interrupt when it is low. When an interrupt is asserted on the pin, this

 

status bit reads back as a 1. This bit is forced low when the TVCLKIN pin is selected as a Clock Input

 

reference to the Dot Clock PLL and NOT an Interrupt pin.

 

0

= Flat Panel Hot Plug Detect asserted

 

1

= Flat Panel Hot Plug Detect not asserted (forced to 1 when used as CLKIN)

 

 

14:11

Reserved.

 

 

10

Flat Panel Hot Plug Detect (edge catcher). This bit is the edge detector for bit 15 above. It is set to 1

 

when it detects a low to high transition.

 

0

= Flat Panel Hot Plug Detect not asserted; bit 15 has not transitioned from 1 to 0 (forced to 0 when

 

 

used as CLKIN)

 

1

= Flat Panel Hot Plug Detect asserted; bit 15 has transitioned from 1 to 0.

 

 

9

Vertical Sync Status.

 

0

= Vertical Sync not asserted

 

1

= Vertical Sync asserted

 

 

8

Display Line Compare Status.

 

0

= Display Line Compare Status not asserted

 

1

= Display Line Compare Status asserted

 

 

7:2

Reserved.

 

 

1

Vertical Blank Status.

 

0

= Vertical Blank Status not asserted

 

1

= Vertical Blank Status asserted

 

 

0

Overlay Registers Updated Status.

 

0

= Overlay Registers have been updated during Vertical Blank Status not asserted

 

1

= Overlay Registers have been updated during Vertical Blank Status asserted

 

 

 

360

Page 360
Image 360
Intel 815 manual Vertical Blank Enable, Overlay Registers Upated Enable, Vertical Sync Status, Display Line Compare Status