5.0 Control Register Definitions-Function 0
Fusion 878A
5.3 Local Registers (Memory Mapped)
PCI Video Decoder
5-10
Conexant
100600B
0x004—Input Format Register (IFORM)
Upon reset IFORM is initialized to 0x58. FORMAT(0) is the LSB.
0x008—Temporal Decimation Register (TDEC)
Upon reset TDEC is initialized to 0x00. DEC_RAT(0) is the LSB. This register enables temporal decimation by
discarding a finite number of fields or frames from the incoming video.
Bits
Type
Default
Name
Description
[7]
RW
0
Reserved
This bit must be set to 0.
[6:5]
RW
10
MUXSEL
Used for software control of video input selection. The Fusion 878A can select
between four composite video sources, or three composite sources, and one
S-Video source.
00 = Select MUX3
01 = Select MUX2
10 = Select MUX0
11 = Select MUX1
[4:3]
R0
11
Reserved
[2:0]
RW
000
FORMAT
Automatic format detection may be enabled or disabled. The NUML bit is used
to determine the input format when automatic format detection is enabled.
000 = Auto format detect enabled
001 = NTSC (M) input format
010 = NTSC without pedestal (Japan)
011 = PAL (B, D, G, H, I) input format
100 = PAL (M) input format
101 = PAL (N) input format
110 = SECAM input format
111 = PAL (N-combination) input format
Bits
Type
Default
Name
Description
[7]
RW
0
DEC_FIELD
Defines whether decimation is by fields or frames.
0 = Decimate frames.
1 = Decimate fields.
[6]
RW
0
FLDALIGN
Aligns the start of decimation with an even or odd field.
0 = Start decimation on the odd field (an odd field is the first field dropped).
1 = Start decimation on the even field (an even field is the first field
dropped).
[5:0]
RW
000000
DEC_RAT
The number of fields or frames dropped out of 60 (NTSC) or 50 (PAL/SECAM)
fields or frames. The 0x00 value disables decimation (all video frames and fields
are output).