W9971CF
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GENERAL DESCRIPTION
Winbond s W9971CF is a highly-integrated VLSI providing high performance graphics acceleration
and TV-quality full screen motion video acceleration for IBM PCs or compatibles. The W9971CF
integrates an NTSC/PAL TV encoder with S-Video or composite video for flicker-free and glueless
TV output. An on-chip RAMDAC and a dual programmable clock synthesizer with a 170 MHz pixel
data rate are also integrated into the chip to simplify system design and reduce cost.
The W9971CF is a high-performance graphics accelerator specially designed for Microsoft
Windows, Mac OS, IBM OS/2, and DOS-based applications. In addition to 100% IBM VGA register-
level compatibility, the W9971CF incorporates a 64-bit graphics engine (GE) to accelerate drawing
functions such as bit block transfer (BitBLT), line drawing, clipping, and hardware cursor
manipulation.
The W9971CF s integrated video accelerator (VA) features high-quality video filtering, bilinear
interpolating scaling along both the X and Y axes, color space conversion and overlay keying. In
addition to accelerating software video playback, the W9971CF also provides an advanced
multimedia video interface for glueless interfacing to major TV decoders such as the Philips
SAA711X and the Brooktree Bt815A/7A/9A. The 16-bit baseline VESA Advanced Feature
Connector (VAFC) and the 8-bit bidirectional IBM Feature Connector are also supported for legacy
video applications. By performing scaling and color space conversion on the fly, the W9971CF
provides high-quality video playback in 1024
768 256-color mode with only 1 MByte of DRAM.
The W9971CF integrates a high quality NTSC/PAL TV encoder to directly interface to TV sets. It
allows an NTSC/PAL TV to be used as the primary or secondary display for Windows-based and
video playback applications. The TV output capabilities are required for Microsoft Entertainment PC
97 designs that do not come bundled with a VGA monitor. These capabilities provide a more
realistic game, video, and multimedia experience for users who use large-screen TVs.
The flexible display memory interface design of the W9971CF allows system designers to select
various types of DRAMs, including 128K
8, 128K
16, 256K
4, 256K
8, and 256K
16. These
DRAMs may be used in either fast page or extended data out (EDO) modes.
The W9971CF supports a glueless interface with the 32-bit PCI Local Bus. Green PC power
management is supported via VESA Display Power Management Signaling (DPMS) and power-
down of the on-chip RAMDAC and clock synthesizers. VESA DDC1 and DDC2 smart monitor
control is also supported.
W9971CF
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FEATURES
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Integrated Video Graphics Controller with TV encoder
64-bit graphics engine
Integrated video accelerator
On-chip 24-bit true color RAMDAC with up to 170 MHz pixel clock rate
On-chip clock synthesizers generating up to 170 MHz VCLK and 100 MHz MCLK
On-chip flicker filtering and NTSC/PAL TV encoder
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GUI Acceleration
64-bit GUI acceleration
Fast frame buffer blts include screen to screen blt, pattern blt, color/font expanding blt,
color/font expansion, rectangle fill, etc.
256 ROPs (Raster Operations) for all 8/15/16/24 bit-per-pixel modes
Transparent blt using the color key for source or destination
Accelerated Bresenham line draw and Short Stroke Vector
Rectangle and line clipping
Built-in 64
64
2 or 32
32
2 hardware cursor
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Video Conferencing Acceleration
Glueless digital camera interface with direct support of CCIR 656 format; analog camera
support with external video decoder
Hardware 2-dimensional down-scaling for local view capture
Hardware dual-video window for local and remote viewing
Built-in Color Space Conversion and 2-dimensional bi-linearly interpolated up-scaling
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Video Playback Acceleration
Video (YUV) and graphics (RGB) shared frame buffer architecture
RGB 5:5:5, RGB 5:6:5, and YUV 4:2:2 packed video formats support
Double buffering and single command page flipping for anti-tearing support
Readable current scan line refresh to allow behind the beam writing in non-double-buffered
scenarios
On-the-fly 2-D bi-linear interpolation and arbitrary up-scaling
On-chip standard CCIR 601 YUV to RGB CSC (Color Space Conversion)
On-the-fly interpolated up-scaling to allow 320
200 game image to be displayed at 640
480 full-screen resolution
Color keying, chroma keying, and window keying to overlay video and graphics streams
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On-the-fly blending of video and graphics streams
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TV Output
Integrated TV encoder to support both NTSC and PAL output
3-line flicker removal filter for flicker reduction
Underscan scaling to support 640x480 modes on NTSC and 800x600 modes on PAL
Support RCA-style composite video and S-Video
Simultaneous output to both VGA monitor and TV
Support simultaneous graphics on VGA and video on TV
TV auto-detect, VGA and TV output can be enabled or disabled independently
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Multimedia Video Interface
VMI Bus v.1.4 compliance
Glueless support for 8/16-bit YUV input and CCIR656 standard, and 16-bit RGB input
Arbitrary down-scaling for the captured video stream
I2C serial bus control for other peripherals such as TV tuner, video decoder, etc.
Glueless Support for 16-bit baseline VESA Advanced Feature Connector (VAFC)
Glueless Support for 8-bit bi-directional pass-through VGA feature connector
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RAMDAC and Dual Clock Synthesizer
Integrated 170 Mhz triple 8-bit RAMDAC
Integrated dual-clock synthesizer for MCLK speeds up to 100 Mhz and VCLK speeds up to
170 Mhz
q
System Bus Interface
Glueless support for zero wait-state, 32-bit PCI bus
Big-endian and little-endian byte ordering support
PCI 2.1 compliant (33 Mhz)
q
Memory Interface
64 or 32-bit interface to support 1-, 2-, or 4-MByte frame
Support FPM and EDO DRAMs with 100 Mhz MCLK
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Extended High Non-Interlaced Refresh and Resolution Support (2 Mbytes DRAM)
1280x1024x256, 85 Hz (157.5 Mhz VCLK)
1024x768x64K, 85 Hz (94.5 Mhz VCLK)
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800x600x16M, 85 Hz (56.25 Mhz VCLK)
1600x1200x256, 65 Hz (173 Mhz VCLK)
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Green PC and Monitor Plug and Play Support
VESA DPMS compliance
VESA DDC2B compliance
q
Software Support
VESA BIOS extension support and VESA monitor timing compliant
Drivers for all major operating systems such as Windows 3.11, 95, NT, OS/2 Warp 3.0,
etc.
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208-pin PQFP Package
Host Bus Interface
PCI Bus
Graphics
Engine
SVGA
Video
Accelerator
DRAM Controller
RAMDAC
TV
Encoder
PLLs
MCLK VCLK
W9971CF
DRAM
BIOS ROM
Xtal/Osc
TV
VGA
Monitor
Multimedia
Video
Interface
Fig. 1. W9971CF Block Diagram
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FUNCTIONAL DESCRIPTIONS
Graphics Engine
The 64-bit graphics engine (GE) is specially designed to improve the performance of Microsoft
Windows applications and other graphical user interface software. Performance is enhanced by
accelerating GUI functions such as BitBLTs, Bresenham line draw, and short stroke vector. The GE
performs several types of BitBLTs, including HostBLT, pattern BLT, color/font expanding BLT,
transparent BLT, color expansion, and rectangle fill, with 256 ROPS on source, pattern, and
destination. The graphics engine operates at all pixel depths in enhanced modes, including 8/16/24
bit-per-pixel modes. A fully Microsoft Windows compatible 64
64
2 or 32
32
2 hardware
cursor, is used to speed up cursor performance and accelerate all graphics operations by eliminating
the CPU overhead associated with cursor manipulation.
Video Accelerator
The Video Accelerator is a high-quality video processor for enhancing and displaying video images.
It not only accelerates software video playback but also facilitates the interface to MPEG-1 video
decoders and TV decoders.
The video accelerator employs back-end color space conversion and a scaling mechanism. Video
and game-generated graphics frames are read from an off-screen buffer and sent to the overlay and
blending control block as the secondary stream. Color space conversion and scaling are performed
along the way. This on-the-fly video acceleration and overlaying ensure game and video playback at
full speed.
Color Space Conversion
The built-in color space converter converts YUV format to 24-bit RGB format according to the CCIR
601-2 Recommendation.
Down Scaling
The down-scaling function is performed by dropping pixels or lines. To support arbitrary scaling
factors, the video accelerator uses a digital differential accumulator (DDA) to drop pixels or lines
smoothly. The scaling factor may range from 1/64 to 63/64.
Scaling up by 2D Interpolation
Rather than duplicating pixels or lines for enlargement, the video accelerator uses a 2-D bilinear
interpolation algorithm to enhance the output for high-quality video display.
The interpolation algorithm creates seven weighted, intermediate values between two original pixels
or lines. This allows a maximum enlargement of 800%. For non-integer scaling, a 10-bit DDA with
1/1024 resolution is used to interpolate pixels by averaging.
2x Scaling
The 2x scaling located in the RAMDAC is used to optionally scale up the overlaid data stream by a
factor of 2. This is used to scale 320
240 game-generated frames to full screen.
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Filtering
The video accelerator provides horizontal RGB or YUV filtering to reduce noise and aliasing
artifacts in the video data stream
Cropping
A rectangular cropping window is supported in the video accelerator for subsampling the incoming
video data stream. Only video located in the cropping window can be stored into the off-screen
buffer.
Alpha Blending
Alpha blending is supported for overlaying the primary stream and secondary stream. The alpha
value can be 1 bit or 3 bits. The 1-bit alpha depth overlaying (also known as a software key) is
supported only for the pixel format of RGB 1:5:5:5, where the alpha bit value of 0 is transparent and
value of 1 is opaque.
An overlay control register specifies the 3-bit alpha value for the primary stream (Kp) and
secondary stream (Ks). Note that Kp + Ks must be
8. The blending equation is [Pp
Kp
+
Ps
Ks]
/
8, where Pp is the primary stream pixel data and Ps is the secondary stream pixel data.
Overlay Control
The overlay controller provides control for overlaying of four input sources: the primary stream
(normally the graphics data), secondary stream, blending stream, and FC/VAFC pass-through data
stream. When the hardware cursor is active, it is overlaid on top of all image streams. The
W9971CF supports a range of advanced keying forms; these include window key, color key, chroma
key, software key (1-bit alpha overlaying in RGB 1:5:5:5 format), external key (FC/VAFC only), and
a logical combination of these keys.
Dual Video Windows
Two video windows may be simultaneously displayed on the monitor. This makes the W9971CF
highly suitable for video conferencing applications. If the two video windows are placed at different
scan lines, they can be scaled separately with different factors.
Flicker Filter and TV Encoder
The W9971CF incorporates an integrated TV encoder, flicker-free filtering, and vertical scaling for
TV output. It directly interfaces with a composite or S-video connector for NTSC or PAL TV output.
The software reads the TV output hardware to detect whether a TV is attached to either S-Video or
composite output connectors. This allows the operating system and graphics drivers to support a
correct display output during the startup sequence (i.e. the correct resolution and refresh rate to
use), and for applications to adjust their user interfaces to the screen s capabilities. Simultaneous
output to a VGA monitor and TV are also supported. If a VGA monitor is not attached, the TV output
works automatically as the primary display. The same image can be simultaneously displayed on
the VGA monitor and TV. Alternatively, graphics may be displayed on the VGA monitor while
display video is displayed on the TV. The graphics adapter must default to modes compatible with
the TV;s output. Adapters manufactured for NTSC countries should default to 60-Hz modes while
adapters manufactured for PAL countries should default to 50-Hz modes.
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When displayed on an interlaced TV, VGA data as well as PC games are often unusable due to the
flicker effect caused by an interlaced monitor. The W9971CF uses a 3-line flicker filtering technique
to provide the best flicker-free TV quality. The vertical underscan scaling is also implemented to
allow 640x480 resolution modes to fit NTSC displays and 800x600 modes to fit PAL displays.
Gamma Correction
In most TV systems, CRT displays have an inherent nonlinear relationship between signal voltage
and light intensity. Linear digital RGB data (normally, the graphics data) need gamma correction to
compensate for the nonlinear CRT characteristics. The linear RGB data is gamma corrected to
obtain a voltage that can be applied to the TV monitor.
Flicker Filter
Without filtering, one contrast VGA line may be encoded into one field of the TV video. This will
cause flicker at 30 Hz with NTSC and 25 Hz with PAL. The W9971CF incorporates an advanced
flicker-free filter to eliminate such problems by providing three filter modes: High Filter (3-line),
Medium Filter (2-line), and No Filter.
TV Auto-detect
In order for the CPU to determine the presence of a TV monitor, the W9971CF includes circuitry to
detect a loaded or unloaded TV output connection. This information can be used to detect the
existence and the type of TV connector used.
Graphics on VGA and Video on TV
The W9971CF can display the same image (including graphics and video) on both a VGA monitor
and a TV. It can also display different images, i.e. graphics on VGA and video on TV. This is
controlled by the TV Video Select bit of the TV Encoder register.
Vertical Scaling
The W9971CF is able to correct vertical overscan via hardware scaling. This allows 640x480
resolution modes to fit onto NTSC displays and 800x600 modes to fit onto PAL displays. This is
done by using a 6-bit DDA which is controlled by the TV Underscan Scaling Control register.
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SYSTEM BLOCK DIAGRAM
Feature Connector
VMI Connector
Camera,
Video Decoder,
etc.
W9971CF
PCI Bus
Display Memory
FPM/EDO DRAM
1/2/4 MBytes
BIOS
ROM
VGA
Monitor
TV
NTSC/PAL
Composite/S-Video
Multimedia
Video Interface
Fig. 3. System Block Diagram
Headquarters:
Winbond Electronics
Corp.
No.4, Creation Rd. III
Science Park, Hsinchu
Taiwan, ROC
T: 886 35 770066
F: 886 35 792647
WWW: www.winbond.com.tw
USA:
Winbond Electronics
North America Corp.
2730 Orchard Parkway
San Jose, CA95134
T: 1 408 9436666
F: 1 408 9436668
Taipei:
115/11F Ming Sheng E.
Rd.
Taipei, Taiwan ROC
T: 886 2 7190505
F: 886 2 7197502
Hong Kong:
Winbond Electronics
[H.K.] Ltd.
Rm 803, World Trade
Square,
Tower II
Kowloon, Hong Kong
T: 852 27516023
F: 852 27552064
W9971CF
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