GENERAL DESCRIPTION
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).

FEATURES
The PELICAN SAA7112 is a video capture device for application at the image port of a VGA controller, with following feature highlights:
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.