Fusion 878A
5.0 Control Register Definitions-Function 0
PCI Video Decoder
5.3 Local Registers (Memory Mapped)
100600B
Conexant
5-21
Vertical Scaling Register, Upper Byte
0x04C—Even Field (E_VSCALE_HI)
0x0CC—Odd Field (O_VSCALE_HI)
Upon reset this register is initialized to 0x60.
Vertical Scaling Register, Lower Byte
0x050—Even Field (E_VSCALE_LO)
0x0D0—Odd Field (O_VSCALE_LO)
Upon reset this register is initialized to 0x00.
0x054—Reserved
A read cycle from this register returns 0x01, and only a write of 0x01 is permitted.
Bits
Type
Default
Name
Description
[7]
RW
0
VSFLDALIGN
Used in conjunction with bit 5 (INT) to align vertical scaling when overlaying
fields at CIF resolution (60/50 Hz mode)
Bits 7/5
00 = Non-interlaced vertical scaling
x1 = Interlaced vertical scaling
10 = Field aligned vertical scaling
[6]
RW
1
COMB
Chroma Comb Enable. This bit determines if the chroma comb is included in
the data path. If enabled, a full line store is used to average adjacent lines of
color information, reducing cross-color artifacts.
0 = Chroma comb disabled
1 = Chroma comb enabled
[5]
RW
1
INT
Used in conjunction with bit 7 (FLDALIGN) to align vertical scaling when
overlaying fields at CIF resolution (60/50 Hz mode)
Bits 7/5
00 = Non-interlaced vertical scaling
x1 = Interlaced vertical scaling
10 = Field aligned vertical scaling
[4:0]
RW
00000
VSCALE_HI
Vertical Scaling Ratio. These 5 bits represent the most significant portion of
the 13-bit vertical scaling ratio register.
Bits
Type
Default
Name
Description
[7:0]
RW
0x00
VSCALE_LO
Vertical Scaling Ratio. These 8 bits represent the LSByte of the 13-bit vertical
scaling ratio register. They are concatenated with 5 bits in VSCALE_HI. The
following equation should be used to determine the value for this register:
VSCALE = (0x10000 – { [ ( scaling_ratio ) – 1] × 512 } ) + 0x1FFF