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4.3.4 Y/C FIFO Unpacking
Display data is always packed into the FIFOs in 64-bit words and must be unpacked before being sent to
the display data pipeline. By default, data is unpacked from right to left.
The 8-bit Y/C mode uses three FIFOs for color separation. Samples are unpacked as shown in
Figure
4-14.
VCLKOUT
VDOUT[9−2]
VDOUT[19−12]
63
Y 31
Y 23
Y 15
Y 7
Y FIFO
63
Cb 15
Cb 7
Cb FIFO
63
Cr 15
Cr 7
Cr FIFO
4.4
Video Output Filtering
The video output filter performs simple hardware scaling and re-sampling on outgoing 8-bit BT.656 or 8-bit
Y/C data. Filtering hardware is disabled during raw data display modes.
4.4.1 Output Filter Modes
The output filter has four modes of operation: no-filtering, 2x scaling, chrominance re-sampling, and 2x
scaling with chrominance re-sampling. Filter operation is determined by the DMODE, SCALE, and
RESMPL bits of the VDCTL.
Table 4-3
shows the output filter mode selection. When 8-bit BT.656 or Y/C display operation is selected,
(DMODE = x00), scaling is selected by setting the SCALE bit and chrominance re-sampling is selected by
setting the RESMPL bit. If 8-bit BT.656 or Y/C display is not selected (DMODE
DMODE
x00
x00
x00
x00
x01
x10
x11
SPRUEM1 – May 2007
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Figure 4-14. 8-Bit Y/C FIFO Unpacking
Y 0
Y 1
Y 2
Cb 0
Cr 0
Cb 1
5655
4847
4039
Y 30
Y 29
Y 22
Y 21
Y 14
Y 13
Y 6
Y 5
5655
4847
4039
Cb 14
Cb 13
Cb 6
Cb 5
5655
4847
4039
Cr 14
Cr 13
Cr 6
Cr 5
Table 4-3. Output Filter Mode Selection
VDCTL Bit
RESMPL
0
0
1
1
x
x
x
Y 3
Y 4
Y 5
Y 6
Y 7
Cr 1
Cb 2
Cr 2
Cb 3
Cr 3
32
31
2423
Y 28
Y 27
Y 20
Y 19
Y 12
Y 11
Y 4
Y 3
32
31
2423
Cb 12
Cb 11
Cb 10
Cb 4
Cb 3
Cb 2
32
31
2423
Cr 12
Cr 11
Cr 10
Cr 4
Cr 3
Little-Endian Unpacking
SCALE
Filter Operation
0
No filtering
1
2x scaling
0
Chrominance re-sampling (full scale)
1
2x scaling with chrominance re-sampling
x
No filtering
x
No filtering
x
No filtering
Video Output Filtering
Y 8
Y 9
Y 10
Y 11
Cb 4
Cr 4
Cb 5
Cr 5
1615
8 7
Y 26
Y 25
Y 24
Y 18
Y 17
Y 16
Y 10
Y 9
Y 8
Y 2
Y 1
Y 0
1615
8 7
Cb 9
Cb 8
Cb 1
Cb 0
1615
8 7
Cr 9
Cr 8
Cr 2
Cr 1
Cr 0
x00), filtering is disabled.
Video Display Port
0
0
0
103
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