426 AMD Geodeā„¢ LX Processors Data Book
Video Processor Register Descriptions
33234H
6.8.3.6 Video Color Key Register (VCK)
30 GB (RO) GLIU Behind (Read Only). This bit set indicates the GLIU line buffer fill is falling behind
the Dot display. This bit clears on read.
This bit is typically set if during vertical downscale, the 2nd line buffer fill has not com-
pleted before the Dot display has started. This does not necessarily indicate an error,
recovery is possible.
29:16 RSVD Reserved.
15 SP Spare. Bit is R/W but has no function.
14 DHD Double Horizontal Downscale. Selects which method data gets written into line buffers.
0: Write data from video interface directly.
1: Write data from video interface averaged each 2 pixels.
This bit should only be set when horizontal downscale greater than 4:1 is desired.
13 COED Coefficient Mode. Selects between 128 and 256 coefficient usage.
0: Use common 256 vert/horz coefficient table.
1: Use separate 128 vert/horz coefficient tables.
When using separate tables, the vertical coefficient should be placed in the lower half of
the coefficient RAM (0-127 = vertical 128-255 = horizontal).
12 LPS La st Pixel Select. Selects method to choose last pixel for the scaler to use.
0: Use video source line size.
1: Use video window size.
The preferred setting is 0. This will avoid unnecessary horizontal mirroring.
11 SP Spare. Bit is R/W but has no function.
10:0 VSL Vid eo Source Lines. Represents the total number of video source lines. For example, a
720x480 video image would have VSL = 480.
VP Memory Offset 028h
Type R/W
Reset Value 00000000_00000000h
SCL Bit Descriptions
Bit Name Description
VCK Register Map
63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32
RSVD
313029282726252423222120191817161514131211109876543210
RSVD VID_CLR_KEY
VCK Bit Descriptions
Bit Name Description
63:24 RSVD (RO) Reserved (Read Only). Reads back as 0.