SAA7112

Video Decoder
` Six analog inputs, internal analog source selectors, (e.g. 6 *CVBS or(2  *YC and 2  *CVBS) or (1  *YC and 4  *CVBS)
` Two analog preprocessing channels, including built in analog anti-alias filters
` Fully programmable static gain for the main channels or Automatic Gain Control (AGC) for the selected CVBS/Y channel
` Two 8 bit video CMOS Analog-to-Digital Converters
(ADCs)
` Automatic Clamp Control (ACC) for CVBS, Y and C
` Switchable white peak control
` On-chip line locked clock generation in accordance with CCIR-601
` Digital PLL for synchronization and clock generation from all standards and non-standard video sources, e.g. consumer grade VTR
` Requires only one crystal (32.11 MHz) for all standards
` Horizontal and vertical sync detection
` Automatic detection of 50/60Hz field frequency, and automatic switching between standards PAL and NTSC
` Luminance and chrominance signal processing for PAL BGHI, PAL N, PAL M, NTSC M, NTSC N, NTSC 4.43 and SECAM
` User programmable luminance peaking or aperture
correction
` Cross-colour reduction for NTSC by chrominance
combination filtering
` PAL delay line for correcting PAL phase errors
` Real time status information output (RTCO)
` Independent Brightness Contrast Saturation (BCS) adjustment for decoder part.
Video Scaler
` Horizontal and vertical down-scaling and up-scaling to randomly sized windows
` Horizontal and vertical scaling range: 2 (zoom) to 1¤64 (icon); vertical zoom might be restricted
` Anti-alias- and accumulating filter for horizontal scaling
` Vertical scaling with linear phase interpolation (6-bit phase accuracy) and accumulating filter for anti-aliasing
` Horizontal phase correct up- and down-scaling for improved signal quality of scaled data, especially for compression and video phone applications, with 6-bit
phase accuracy
` Two independent programming sets for scaler part, to define two 'ranges' per field or per frame
` Field-wise switching between decoder-part and expansion port input
` Brightness, contrast and saturation controls for scaled outputs.
VBI-data decoder and text slicer
` versatile VBI-data decoder, slicer, clock regeneration and byte synchronization; e.g. for WST, NABST, Close Caption, WSS, etc.
Audio clock generation
` Generation of a field locked audio master clock to support a constant number of audio clocks per video field
` Generation of an audio serial and left/right (channel) clock signal.
Digital I/O interfaces
` Real time signal port (R-port), including continuous line locked reference clock and real time status information
` Bidirectional expansion port (X-port) with half duplex functionality (D1), 8-bit YUV
output from decoder part, real time, or
input to scaler part, e.g. video from MPEG-decoder
` Video image port (I-port) configurable for 8-bit (16-bit) data in master mode (own clock), or slave mode (external clock), with auxiliary timing and hand shake signals
` 8-bit data Host port (H-port) for 16-bit extension of I-port
` Discontinuous data streams supported
` 32-word *4 bytes FIFO register for video output data
` 16-word *4 bytes FIFO register for decoded VBI output data Scaled 4 : 2 : 2, 4 : 1 : 1 YUV output
` Scaled 8-bit luminance only and raw data output
` Decoded VBI data output. miscellaneous
` Power-on control
` Programming via I2C-bus, or parallel image data port (full read-back ability by an external controller)
` Chip enable function (reset for the clock generator).

The PELICAN SAA7112 is a video capture device for applications at the image port of VGA controllers. The SAA7112 is a combination of a two channel analog preprocessing circuit including source-selection, anti-aliasing filter and ADC, an automatic clamp and gain control, a Clock Generation Circuit (CGC), a digital multistandard decoder and a SAA7140B based scaler, including variable horizontal and vertical up and down scaling and a brightness, contrast and saturation control circuit (see Fig.1).

SAA7112 is a highly integrated circuit for desktop video applications. The decoder is based on the principle of line-locked clock decoding and is able to decode the colour of PAL, SECAM and NTSC signals into CCIR-601 compatible colour component values. The SAA7112 accepts as analog inputs CVBS or S-video (Y-C) from TV or VCR sources, including weak and distorted signals.

An Expansion port for digital video (bidirectional half duplex, D1 compatible) is also supported to connect to MPEG or video phone CODEC. At the so called image port the SAA7112 supports 8-bit (16-bit) wide output data with auxiliary reference data for interfacing to VGA controllers The target application of SAA7112 for PELICAN is to capture and scale video images, to be provided as digital video stream through the image port of a VGA controller, for display via VGAs frame buffer, or for capture to system memory.

In parallel the SAA7112 incorporates also provisions for capturing the serially coded data in the vertical blanking interval (VBI-data). Two principal functions are available: to capture raw video samples and a versatile data slicer (data recovery) unit.

The SAA7112 incorporates also a field locked audio clock generation. This function ensures that there is always the same number of audio samples associated with a field, or a set of fields. SAA7112 prevents the loss of synchronization between video and audio, during capture or playback.

The circuit can be controlled via the I²C-bus or via its fast parallel programming mode of the image port interface (full write/read capability).