1.0 Functional Description
CX25870/871
1.3 Device Description
Flicker-Free Video Encoder with Ultrascale Technology
1.3.42 HDTV Output Mode
The CX25870/871 includes an HDTV Output Mode that generates the analog
RGB or analog YPBPR component video outputs necessary for driving an
HDTV’s HD input port.
While generating HDTV outputs, the device accepts RGB or YPRPB digital
data in a 480p, 720p, or 1080i ATSC resolution. After a pipeline delay, it outputs
either analog RGB or analog YPBPR signals and automatically inserts trilevel
synchronization pulses (when necessary) and vertical synchronizing ‘broad
pulses’. The output waveforms, input data requirements and all configuration
details are explained in Appendix E. The device complies with all major SMPTE
and EIA standards governing the HDTV resolutions.
1.3.43 SCART Output
In this mode of operation, the CX25870/871 can be used successfully to provide
one full Red/Green/Blue/Composite (or optionally, a 2-signal Luminance and
Chrominance) SCART/Peritel output to drive SCART-compatible televisions or
VCRs. Many PAL/European TVs being manufactured now have SCART
compatible sockets, that allows the television and the set top box, graphics card,
or game console driving it to work in RGB color instead of the standard
composite. The picture quality for full SCART is significantly better due to the
individual RGB Composite signals being sent directly to the TV color guns. This
is opposed to the TV having to modulate and decode the RGB signals from
another color format. This ultimately yields a crisper picture.
On power-up, the CX25870/871 will output NTSC or PAL standard-definition
television outputs depending on the state of the PAL pin. To switch the device into
SCART Output Mode with three sync-less Red/Green/Blue (RGB) analog outputs
and a single Composite (CVBS) PAL video output from the fourth DAC, program
the encoder into a satisfactory PAL output mode and then perform the sequence
of serial writes found in Table 1-24.
1-76
Conexant
100381B
CONEXANT [ CONEXANT SYSTEMS, INC ]
