Datasheet
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9.3.6 Vertical Scaling Field 1 Control
9.3.7 Vertical Scaling Field 2 Control
9.3.8 Scaler Output Active Pixels
TVP5154
4-CHANNEL LOW-POWER PAL/NTSC/SECAM VIDEO DECODER
WITH INDEPENDENT SCALERS AND FAST LOCK
SLES163A – MARCH 2006 – REVISED JULY 2006
These registers allow the output data stream to toggle between unscaled and scaled data on a field basis.
By setting Field mode[n] appropriately, it is possible to use the available output bandwidth to interleave
unscaled and scaled frames to achieve reduced frame rates, while still maintaining compatibility with
legacy data receivers. These registers can also be used to reduce the frame rate of either unscaled data
or scaled data by disabling fields within the sequence.
A counter automatically moves from Field mode[0] to Field mode[n] where n can be 0 through 15, then
returns back to Field mode[0]. Depending on the value of Field mode[n], either unscaled data, scaled data,
or no data is sent for the current frame.
00 = Unscaled data
01 = Null frame (no SAV/EAV sequence will be generated)
10 = Scaled data
11 = Reserved
The values programmed for registers 3A8h and 3A9h are different for NTSC (also NTSC4.43 and PAL-M)
and for PAL (also PAL-Nc and SECAM).
Address 3A8h
Default 0h
7 6 5 4 3 2 1 0
V_Field1[7:0]
15 14 13 12 11 10 9 8
Reserved V_Field1[8]
Vertical scaling initial value in field 1 [8:0]: Initial value of vertical accumulator for field 1
For NTSC:
V_Field1 = (1.5 × V_Field2) – 128
If V_Field 1 is negative, add V_Field2 to V_Field1 and add V_Field2 to V_Field2 until V_Field1 is positive.
For PAL:
V_Field1 = (Vdesired/Vactive) × 256
Address 3A9h
Default 0h
7 6 5 4 3 2 1 0
V_Field2[7:0]
15 14 13 12 11 10 9 8
Reserved V_Field2[8]
Vertical scaling initial value in field 2 [8:0]: Initial value of vertical accumulator for field 2
For NTSC:
V_Field2 = (Vdesired/Vactive) × 256
For PAL:
V_Field2 = (1.5 × V_Field1) – 128
If V_Field 2 is negative, add V_Field1 to V_Field2 and add V_Field1 to V_Field1 until V_Field2 is positive.
Address 3ABh
Default 2D0h
7 6 5 4 3 2 1 0
SCAL_PIXEL[7:0]
15 14 13 12 11 10 9 8
Reserved SCAL_PIXEL[9:8]
SCAL_PIXEL [9:0]: Scaler active pixel outputs per line
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