Intel 815 manual DISPSLC-Display Scan Line Count Range Compare, Inclusive / Exclusive

Models: 815

1 423
Download 423 pages 44.71 Kb
Page 354
Image 354

Intel® 815 Chipset: Graphics Controller PRM, Rev 1.0

R

20.2.DISP_SLC—Display Scan Line Count Range Compare

Memory Offset Address:

70004h

Default:

0000h

Attributes:

Read only

The Top and Bottom Line Count Compare registers are compared with the display line values from CRTTG (the CRT timing generator) or the TV/FP timing generator, depending upon whether the TV/FP timing generator is enabled and not in FP VESA VGA Mode (LCDTV_C[31]=1 AND LCDTV_C[28]=0) or not. The line counter changes at the leading edge of HSYNC. It can be safely read during the display enable active time. The Top compare register operator is a less than or equal, while the Bottom compare register operator is a greater than or equal. The results of these two comparisons are communicated to the command stream controller for generating interrupts, status, and command stream flow control (wait for scanline). These registers can be loaded from the command stream and read through the PCI.

When in TV/FP centering mode, scan line 0 is the first active scan line of the TV/FP, not the first line of the centered active display.

 

31

30

28

27

16

 

 

In/Ex

Reserved

 

 

Top Line Count Compare for Display SLC [11:00]

 

 

 

 

 

 

 

 

 

15

 

12

11

0

 

 

 

Reserved

 

 

Bottom Line Count Compare for Display SLC [11:00]

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bit

 

 

 

Descriptions

 

31Inclusive / Exclusive.

1 = Inclusive: within the range.

0 = Exclusive: outside of the range.

30:28

Reserved.

27:16

Top Line Count Compare for Display SLC [11:00]. This register is used as the top comparison (less

 

than or equal to) value with the display vertical line counter.

 

 

15:12

Reserved.

 

 

11:0

Bottom Line Count Compare for Display SLC [11:00]. This register is used as the bottom

 

comparison (greater than or equal to) value with the display vertical line counter.

354

Page 354
Image 354
Intel 815 manual DISPSLC-Display Scan Line Count Range Compare, Inclusive / Exclusive