SAA7196 Datasheet, PDF (3/76 Pages) NXP Semiconductors – Digital video decoder, Scaler and Clock generator circuit DESCPro

Philips Semiconductors
Digital video decoder, Scaler and Clock
generator circuit (DESCPro)
Product specification
SAA7196
1 FEATURES
• Digital 8-bit luminance input [video (Y) or CVBS]
• Digital 8-bit chrominance input [CVBS or C from CVBS,
Y/C, S-Video (S-VHS or Hi8)]
• Luminance and chrominance signal processing for main
standards PAL, NTSC and SECAM
• Horizontal and vertical sync detection for all standards
• User programmable luminance peaking for aperture
correction
• Compatible with memory-based features (line-locked
clock, square pixel)
• Cross colour reduction by chrominance comb-filtering
for NTSC or special cross-colour cancellation for
SECAM
• UV signal delay lines for PAL to correct chrominance
phase errors
• Square-pixel format with 768/640 active samples per
line
• The bidirectional expansion port (YUV-bus) supports
data rates of 780 × f_H (NTSC) and 944 × f_H (PAL,
SECAM) in 4 : 2 : 2 format
• Brightness, contrast, hue and saturation controls for
scaled outputs
• Down-scaling of video windows with 1023 active
samples per line and 1023 active lines per frame to
randomly sized windows
• 2D data processing for improved signal quality of scaled
luminance data, especially for compression applications
• Chroma key (α-generation)
• YUV to RGB conversation including anti-gamma
ROM tables for RGB
• 16-word output FIFO (32-bit words)
• Output configurable for 32-, 24- and 16-bit
video data bus
• Scaled 16-bit 4 : 2 : 2 YUV output
• Scaled 15-bit RGB (5-5-5+α) and 24-bit (8-8-8+α)
output
• Scaled 8-bit monochrome output
• Line increment, field sequence (odd/even,
interlace/non-interlaced) and vertical reset control for
easy memory interfacing
• Output of discontinuous data bursts of scaled video data
or continuous data output with corresponding qualifier
signals
• Real-time status information
• I²C-bus control
• Only one crystal of 26.8 MHz required
• Clock generator on chip.
2 GENERAL DESCRIPTION
The CMOS circuit SAA7196, digital video decoder, scaler
and clock generator (DESCPro), is a highly integrated
circuit for DeskTop Video applications. It combines the
functions of a digital multistandard decoder (SAA7191B),
a digital video scaler (SAA7186) and a clock generator
(SAA7197).
The decoder is based on the principle of line-locked clock
decoding. It runs at square-pixel frequencies to achieve
correct aspect ratio. Monitor controls are provided to
ensure best display.
Four data ports are supported:
• Port CVBS7 to CVBS0 of input interface; used in Y/C
mode (see Fig.1) to decode digitized luminance and
chrominance signals (digitized in two external ADCs).
In normal mode, only this input port is used and only one
ADC is necessary (see Fig.4)
• Port CHR7 to CHR0 of input interface; used in Y/C
mode (see Fig.1) to decode digitized luminance and
chrominance signals (digitized in two external ADCs)
• 32-bit VRAM output port; interface to the video memory.
It outputs the down-scaled video data; different formats
and operation modes are supported by this circuit
• 16-bit expansion port; this is a bidirectional port.
In general, it establishes the digital YUV as known from
the SAA71x1 family of digital decoders. In addition, the
expansion port is configurable to send data from the
decoder unit or to accept external data for input into the
scaler. In input mode the clock rate and/or the sync
signals may be delivered by the external data source.
Decoder and scaler units can run at different clock rates.
The decoder processing always operates with a Line
Locked Clock (LLC). This clock is derived from the CVBS
signal and is suited best for memory based video
processing; the LLC clock is always present. The scaler
clock may be driven by the LLC clock or by an external
clock depending on the configuration of the expansion
port.
1996 Nov 04
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