5.0 Control Register Definitions-Function 0
Fusion 878A
5.3 Local Registers (Memory Mapped)
PCI Video Decoder
5-20
Conexant
100600B
0x044
—
White Crush Up Register (WC_UP)
This control register may be written to or read by the MPU at any time, and upon reset it is initialized to 0xCF.
UPCNT(0) is the least significant bit.
0x048—Output Format Register (OFORM)
Upon reset OFORM is initialized to 0x00. OFORM(0) is the LSB.
Bits
Type
Default
Name
Description
[7:6]
RW
3
MAJS
These bits determine the majority comparison point for the White Crush Up
function.
00 = 3/4 of maximum luma value
01 = 1/2 of maximum luma value
10 = 1/4 of maximum luma value
11 = Automatic
[5:0]
RW
0xF
UPCNT
The value programmed in these bits accumulates once per field or frame, when the
majority of the pixels in the active region of the image are below a selected value.
The accumulated value determines the extent to which the AGC value needs to be
raised in order to keep the SYNC level proportionate with the white level. The UPCNT
value is assumed positive, for example:
3F = 63
3E = 62
.
.
.
.
.
.
.
.
.
00 = 0
Bits
Type
Default
Name
Description
[7]
RW
0
RANGE
Luma Output Range. This bit determines the range for the luminance output on
the Fusion 878A. Limit the range when using the control codes as video timing.
0 = Normal operation (Luma range 16–253, chroma range 2–253).
Y = 16 is black (pedestal).
Cr, Cb = 128 is zero color information.
1 = Full-range Output (Luma range 0–255, chroma range 2–253)
Y = 0 is black (pedestal).
Cr, Cb = 128 is zero color information.
[6:5]
RW
00
CORE
Luma Coring. These bits control the coring value used by the Fusion 878A. When
coring is active and the total luminance level is below the limit programmed into
these bits, the luminance signal is truncated to 0.
00 = 0 no coring
01 = 8
10 = 16
11 = 32
[4:0]
RW
00000
Reserved