AMD Geode LX 800@0.9W - Manual (Page 456)

456 AMD Geode™ LX Processors Data Book
Video Processor Register Descriptions 33234H
6.8.3.46 Dither and Frame Rate Control (DFC)
VP Memory Offset 418h
Type
R/W
Reset Value 00000000_00000000h
DFC 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
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
RSVD
RR
S
RSVD RV
R
S
RSVD BC DBS
DENB
DFC Bit Descriptions
Bit Name Description
63:13 RSVD (RO) Reserved (Read Only). Reads back as 0.
12 RRS RAM or ROM Select. This bit selects either internal ROM or internal RAM as the source of the
dither patterns.
0: Selects fixed (internal to FP) ROM for dither patterns. (Default)
1: Selects programmable (internal to FP) RAM for dither patterns.
To update the dither RAM, this bit must = 1. See FP Memory Offset 448h[6].
11 RSVD (RO) Reserved (Read Only). Reads back as 0.
10 RVRS Negative Image. This converts the black to white and white to black and all colors in between
to their logical inverse to provide a negative image of the original image. It acts as though the
incoming data stream were logically inverted (1 becomes 0 and 0 becomes 1).
0: Normal display mode.
1: Negative image display mode.
9:7 RSVD (RO) Reserved (Read Only). Reads back as 0.
6:4 BC Base Color. This field is used in conjunction with the DBS field (bits [3:1[). The value in bits
[6:4] sets the base color used prior to dithering.
000: Select 1 MSB for base color use prior to dithering.
001: Select 2 MSB for base color use prior to dithering.
010: Select 3 MSB for base color use prior to dithering.
011: Select 4 MSB for base color use prior to dithering.
100: Select 5 MSB for base color use prior to dithering.
101: Select 6 MSB for base color use prior to dithering.
110: Select 7 MSB for base color use prior to dithering.
111: Select 8 MSB for base color, no dithering.
3:1 DBS Dithering Bits Select. This field is used to select the number of bits to be used for the dither-
ing pattern. Dither bits are the LSBs of each pixel’s final color value; FRM bits are the MSBs.
000: Selects 6 bits as dither bits.
001: Selects 5 bits as dither bits.
010: Selects 4 bits as dither bits.
011: Selects 3 bits as dither bits.
100: Selects 2 bits as dither bits.
101: Selects 1 bits as dither bits.
110, 111: Reserved.