Graphics Adapter Basic Features

Basic PC 97

Workstation PC 97

Entertainment PC 97

800x600x16 bpp

1024x768x16 bpp

1024x768x16 bpp

640x480x8 bpp, small LCD

This section defines requirements for basic features for graphics adapters.

5. General device requirements

Required

These include the standard requirements for a Plug and Play device identifier, automated software-only settings for device configuration, standard device drivers and Windows-based installation, and icons for external connectors. For more information, see the "Basic PC 97" chapter of this guide.

6. PC 97 minimum resolution

A Basic PC 97 system must contain a graphics adapter that permits a color depth of 16 bpp, minimum. These are the minimum resolution requirements:

Basic PC 97: 800x600x16 bpp for Windows desktop and 640x480x16 bpp double buffered for DirectDraw-based full-screen applications.
The minimum required resolution for a 7"– 10" LCD internal display is 640x480x8 bpp.
Workstation PC 97: 1024x768x16 bpp.
Entertainment PC 97: 1024x768x16 bpp.

Display RAM requirements are tied directly to the minimum graphics resolution supported by the adapter. The requirement to support double buffering implies 1.5 MB of display RAM. However, PC 97 requirements do not specify minimum display RAM support; rather, the adapter designer can implement any solutions for supporting the minimum resolution requirements.

Note When the user selects 1024x768 resolution, by default the graphics adapter must use a non-interlaced refresh rate.

7. Graphics operations use relocatable registers only

Basic PC 97	Workstation PC 97	Entertainment PC 97

Required	Required	Required

VGA registers must not be used to perform graphics operations such as bit-blting, palette setting, and pointer movement. The registers used for these graphics operations can be either I/O locations or memory-mapped locations, but must be relocatable. Normal operation of the system — except system startup and mode setting— should never require using base VGA registers.

8. VESA specifications for ergonomic timing rates: 75 Hz for 1024x768

Required

Recommended: 85 Hz for 1024x768.

The graphics adapter, at a minimum, must support the ergonomic timings documented in the current version of VESA and Industry Standards and Guidelines for Computer Display Monitor Timing for all resolutions up to 1280x1024 that are supported by the monitor. Higher scan rates are preferable under standards published by VESA.

9. Support one or more pixel orderings for color depth

Required

Graphics adapters that support packed-pixel frame buffers at color depths greater than 8 bpp should support one or more of the pixel orderings for color depth that are supported by the Windows DIB engine. (Color ordering is shown from the most-significant bit (MSB) to the least-significant bit (LSB.)

Format	Color ordering

15 bpp	1 undefined, 5 red, 5 green, 5 blue (URRR RRGG GGGB BBBB)
16 bpp	5 red, 6 green, 5 blue (RRR RRGGG GGGB BBBB)
24 bpp	8 red, 8 green, 8 blue (RRRR RRRR GGGG GGGG BBBB BBBB)
32 bpp	8 undefined, 8 red, 8 green, 8 blue (UUUU UUUU RRRR RRRR GGGG GGGG BBBB BBBB)

10. Downloadable RAMDAC entries to support image color matching

Recommended

For graphics adapters that support 24-bit or higher displays, downloadable RAM digital-to-analog converter (RAMDAC) entries should be included to perform gamma correction in hardware.

Note This will become a requirement in 1998.

11. Graphics adapter supports DDC 2.0 Level 2 monitor detection

Required

This requirement is based on the Display Data Channel DDC 2.0 specification (DDC2B), which defines the communication channel between the display and host system. The adapter must be able to report to the operating system or its driver whether a VGA or an SVGA monitor is attached. The software can use this information to properly manage output to the various displays and to prevent the disabling of TV output if no monitor is attached.

12. Hardware arithmetic stretching

Basic PC 97	Workstation PC 97	Entertainment PC 97

Required (horizontal)	Required (horizontal)	Required (horizontal and vertical)

To support accelerated software playback of motion video, all graphics adapters should support scaling and interpolation to any size window, up to full screen, at any video mode. Doubling (pixel replication) is not an acceptable implementation.

For Basic PC 97 and Workstation PC 97, the minimum requirement is horizontal linear or better, up/down arithmetic stretching to any size window.
Recommended: Bilinear or better horizontal and vertical stretching.
For Entertainment PC 97, the minimum requirement is bilinear or better horizontal and vertical, up/down arithmetic stretching to any size window.

Hardware stretching also allows 3-D to be rendered to a smaller back buffer (therefore at higher speeds) and scaled up to the front buffer. Although integral stretches are useful, arbitrary stretches are better because they allow dynamic resizing of the back buffer to maintain constant high frame rates.

Note This capability is recommended but not required for mobile PCs.

13. YUV off-screen surfaces for color space conversion

Required

To support accelerated software playback of video, all graphics cards must support off-screen surfaces in either of the two following packed YUV 4:2:2 sampled formats:

YUY2: A byte stream for every pixel in this order: Y1, U, Y2, V
UYVY: A byte stream for every pixel in this order: U, Y1, V, Y2

The YUV color space and intensity range is defined by the ITU-R BT.601-4 standard (previously called CCIR-601), where U is CB and V is CR.

These formats use less memory while maintaining high quality, and YUV is the native format for many image and video compression standards.

Note This capability is recommended but not required for mobile PCs.