General Description

The SAF7115 is a video capture device that, due to its improved comb filter performance and 10-bit video output capabilities, is suitable for various applications such as In-car video reception, In-car entertainment or In-car navigation.

The SAF7115 is a combination of a two channel analog preprocessing circuit and a high performance scaler.

The two channel analog preprocessing circuit includes source-selection, an anti-aliasing filter and Analog-to-Digital Converter (ADC) per channel, an automatic clamp and gain control, two Clock Generation Circuits (CGC1 and CGC2) and a digital multi standard decoder that contains two-dimensional chrominance/luminance separation utilizing an improved adaptive comb filter.

The high performance scaler has variable horizontal and vertical up and down scaling and a brightness/contrast/saturation control circuit.

The decoder is based on the principle of line-locked clock decoding and is able to decode the color of PAL, SECAM and NTSC signals into ITU-601 compatible color component values. The SAF7115 accepts CVBS or S-video (Y/C) from TV or VCR sources as analog inputs, including weak and distorted signals.

The expansion port (X-port) for digital video (bi-directional half duplex, D1 compatible) can be used to either output unscaled video using 10-bit or 8-bit dithered resolution or to connect to other external digital video sources for reuse of the SAF7115 scaler features.

The enhanced image port (I-port) of the SAF7115 supports 8-bit and 16-bit wide output data with auxiliary reference data for interfacing, e.g. with VGA controller applications. It is also possible to output video in square pixel formats accompanied by a square pixel clock of the appropriate frequency.

The SAF7115 also incorporates provisions for capturing the serially coded data in the Vertical Blanking Interval (VBI-data) of several standards in parallel. Three basic options are available to transfer the VBI data to other devices:

• Capturing raw video samples, after interpolation to the required output data rate, using the scaler and transferring the data to a device connected to the I-port
• Slicing the VBI data using the built-in VBI data slicer (data recovery unit) and transferring the data to a device connected to the I-port
• Slicing the VBI data using the built-in VBI data slicer and reading out the sliced data through the I²C-bus (for several slow VBI data type standards only)

The SAF7115 incorporates a frame locked audio clock generation. This function ensures that there is always the same number of audio samples associated with a frame, or a set of fields. This prevents the loss of synchronization between video and audio, during capture or playback. Furthermore, there is an option to use a second analog onboard PLL to enhance this audio clock to a low jitter frame locked audio clock.

The SAF7115 is controlled through the I²C-bus with full write/read capability for all programming registers and a bit-rate of up to 400 kbit/s. See Ref. 1 for a detailed register description, pin strapping and applications.

Key Features

Video acquisition

• Six analog inputs, internal analog source selectors, e.g. (6 x CVBS) or (2 x Y/C and 2 x CVBS) or (1 x Y/C and 4 x CVBS)
• Two differential (bi-phase) video inputs as an alternative
• Two built-in analog anti-alias filters
• Two improved 9-bit CMOS ADCs in differential CMOS style at two-fold ITU-656 oversampling (27 MHz)
• Fully programmable static gain or Automatic Gain Control (AGC) for the selected CVBS or Y/C channel
• Automatic Clamp Control (ACC) for CVBS, Y and C
• Switchable white peak control. Two 9-bit video CMOS ADCs, digitized CVBS or Y/C
• Signals are available on the expansion port (X-port)
• Requires only one crystal (32.11 MHz or 24.576 MHz) for all standards
• Independent gain and offset adjustments for raw data path

Comb filter video decoder

• Digital PLL for synchronization and clock generation from all standard and non-standard video sources e.g. consumer grade Video Tape Recorders (VTR)
• Automatic detection of 50 Hz and 60 Hz field frequencies
• Automatic recognition of all common broadcast standards
• Enhanced horizontal and vertical sync detection
• Luminance and chrominance signal processing for:
  • PAL BGDHIN
  • Combination-PAL N
  • PAL M
  • NTSC M
  • NTSC-Japan
  • NTSC 4.43
  • SECAM (50 Hz/60 Hz)
• PAL delay line for correcting PAL phase errors
• Improved 2/4-line comb filter for two dimensional chrominance/luminance-separation operating with adaptive comb filter parameters.
  • Increased luminance and chrominance bandwidth for all PAL and NTSC-standards
  • Reduced cross color and cross luminance artefacts
• Independent Brightness Contrast Saturation (BCS) – adjustment for decoder part
• User programmable sharpness control
• Detection of copy protected input signals:
  • According to Macrovision standard
  • Indicating the level of protection
• Automatic TV/VCR detection
• 10-bit wide video output at comb filter video decoder
• X-port video output either as:
  • Noise shaped 8-bit ITU-656 video or
  • Full 10-bit ITU-656 interface (DC-performance 9-bit)

Video scaler

• Horizontal and vertical down-scaling and up-scaling to randomly sized windows
• Horizontal and vertical scaling range: variable zoom to 1/64 (icon) (note: H and V zoom are restricted by the transfer data rates)
• Vertical scaling with linear phase interpolation and accumulating filter for anti-aliasing (6-bit phase accuracy)
• Conversion to square pixel format
• Generation of a video output stream with improved synchronization grid at the I-port
• Two independent programming sets for scaler part, to define two regions (e.g. for different scaling for VBI and active picture) per field or sequences over frames
• Fieldwise switching between decoder part and expansion port (X-port) input
• Brightness, contrast and saturation controls for scaled outputs

VBI data slicer

• Versatile VBI-data decoder, slicer, clock regeneration and byte synchronization, e.g.:
  • WST525/WST625 (CCST)
  • VPS
  • US/European Close Caption (CC)
  • WSS525 (CGMS), WSS625
  • US NABTS
  • VITC 525/VITC 625
  • Gemstar 1x
  • Gemstar 2x
  • Moji
• I²C-bus read-back of the following decoded data types:
  • US Close Caption (CC)
  • European Close Caption (CC)
  • WSS525 (CGMS)
  • WSS625 (CGMS)
  • Gemstar 1x
  • Gemstar 2x

Clock generation

• On-chip line locked clock generation according ITU-601
• Generation of a frame locked audio master clock to support a constant number of audio clocks per video field
• Second onboard analog Phase-Locked Loop (PLL) to be used for:
  • On-chip line locked square pixel clock generation for PAL and NTSC square pixel video output or
  • The generation of a low jitter frame locked audio clock from the audio master clock through reuse of the analog square pixel PLL. The audio clock frequencies supported are 256 x fs, 384 x fs and 512 x fs (fs = 32 kHz, 44.1 kHz or 48 kHz)

General features

• CMOS 3.3 V device with 5 V tolerant digital inputs and I/O ports
• Programming through serial I²C-bus, full read-back ability by an external controller, bit-rate up to 400 kbit/s
• Software controlled power saving stand-by modes
• Boundary Scan Test circuit complies to the IEEE Std. 1149.b1-1994

Block Diagram

Downloads

Product brief

Datasheet