SDA9189X Datasheet, PDF (27/55 Pages) Siemens Semiconductor Group – Quarter PIP Processor

SDA 9189X
processings. Three different characteristics of the output stage of this signal are
available. An open source, an open drain, or a TTL output can be selected via I²C Bus
(SELMOD).
2.4.11 Blanking Signals
In case of full screen background insertion the circuit has to generate output signals with
correctly positioned line blanking intervals relative to the horizontal synchronization
pulses of the parent channel. This can be achieved by a programmable delay (BLKDEL).
A field-blanking interval with a length of 16 lines is also provided. It is triggered by the
vertical synchronization pulse of the parent channel (VSP). The generation of this
field-blanking signal can be activated via I²C Bus (VERBLK = ‘1’).
2.4.12 Pedestal for the Chrominance Signals
Both components of the chrominance signal are equipped with a programmable
pedestal (white balance, PEDESTU, PEDESTV). The pedestal values are fed to the
digital to analog converters during the line blanking intervals. For each component a 4-bit
value in 2’s complement code is defined via I²C Bus. Building up the 6-bit input words of
the digital to analog converters these 4 bits are used as LSBs. The missing two MSBs
are complemented by sign extension. In this way pedestal values from – 8 to + 7 LSBs
of the digital to analog converters can be achieved.
2.5 Digital-to-Analog Conversion
2.5.1 Analog Video Outputs
The IC includes three 6-bit digital to analog converters for the video outputs. Each
converter supplies a current through an external resistor that is placed between V_SSA and
OUT1, OUT2, OUT3 respectively. The current is controlled by a digital control circuit.
2.5.2 Analog Control Signal
The additional 6-bit digital to analog converter that provides an analog control signal
(e.g. for color decoder adjustment) is fed directly by a 6-bit signal programmable via
I²C Bus. No external resistor is needed at output ANACON.
2.6 On-Screen Display
2.6.1 Display Format
The on-screen display allows to insert a block of 5 characters into each of the PIP
pictures. The characters are placed in a box (background) with a width of 64 pixels and
a height of 12 lines. This box is situated in the upper left corner of the PIP pictures. The
Semiconductor Group
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