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SAB9082

NTSC Picture-In-Picture (PIP) controller

Philips Electronics 

Philips Semiconductors

NTSC Picture-In-Picture (PIP) controller

Preliminary specification

SAB9082

MPIPON (DOUBLE WINDOW)

Bit MPIPON is used to switch the main channel PIP on

(logic 1) or off (logic 0).

SPIPON

Bit SPIPON is used to switch the subchannel PIPs on

(logic 1) or off (logic 0).

PRIO

The priority bit decides whether the main channel PIP (Prio

set to logic 0) or the subchannel PIP (Prio set to logic 1)

will be on top when both PIPs overlap.

S1FLD

If S1FLD is set to logic 0, two fields are used for the live

PIP. When a 50/60 Hz or a 60/50 Hz mode is detected, the

SAB9082 automatically switches to the 1-Field mode

(1-Field resolution vertically).

If S1FLD is set to logic 1, only one field is used. This

causes joint line errors but saves memory. This bit should

not be set in normal modes.

SFREEZE

With SFreeze set to logic 1, the current live subchannel

PIP will be frozen. If set to logic 0, it is unfrozen.

ALGOFF

In double window mode, precautions are taken to prevent

a joint line error. Under some conditions, this feature

should be switched off. This can be realized by setting this

bit to logic 1. Normally, bit AlgOff should be set to logic 0.

DNONINT

In normal mode (this bit is logic 0), the SAB9082 calculates

whether a signal is non-interlaced and reacts accordingly.

With bit DNonint set to logic 1, the display channel is

forced into the non-interlaced mode. In the non-interlaced

mode, only one field is used during the processing of the

PIPs.

PIPMODE

Byte PipMode determines the PIP modes for the SAB9082

are shown in Table 2.

Table 2 PIP modes

PipMode<2:0>

000

001

010

011

100

111

MODE

double window mode

replay PIP

multistandard PIP 3

multistandard PIP 6

reserved

multistandard PIP 6 split

SHRED AND SVRED (DOUBLE WINDOW)

Bits SHRed<5:0> and SVRed<6:0> determine the

reduction factors in the double window mode.

The horizontal reduction is equal to SHRed/96; the vertical

reduction is equal to SVRed/96. SHRed should lie in the

range from 0 to 48; if set to logic 0, the PIP is off. SVRed

should lie in the range from 0 to 96; if set to logic 0, the PIP

is off.

When the horizontal reduction factor is 48/96,

704 samples are processed. The horizontal reduction

factor is linear; therefore, when it is 24/96, 352 samples

are processed. The same holds for the vertical reduction

factor but then with the number of lines. For NTSC, the

number of processed lines can be calculated from

SVRed/96 × 228 lines.

SHRED AND SVRED (REPLAY)

In the replay mode, the range of SHRed and SVRed is

limited as follows: SHRed = 12; SVRed = 24, 16 or 12.

This leads to a fixed horizontal reduction factor of 1⁄8; and

to a variable vertical reduction factor of 1⁄4, 1⁄6 or 1⁄8. Note

that the resulting replay PIP can be expanded by using

SHBlow and/or SVBlow.

SHPIC AND SVPIC (MULTISTANDARD PIP MODES)

Bytes SHPic and SVPic control the picture size in the

multistandard PIP modes. The horizontal range is

256 steps of four 28 MHz clock periods. The vertical range

is 256 steps of one line/field.

In the double window and replay modes, the picture size is

determined by the reduction factors (SHRed and SVRed)

and bits HBlow and VBlow.

1999 Nov 12

10

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