Browse Prior Art Database

Local Video Memory Access Interface

IP.com Disclosure Number: IPCOM000115969D
Original Publication Date: 1995-Jul-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 4 page(s) / 105K

Publishing Venue

IBM

Related People

Andric, T: AUTHOR [+5]

Abstract

Disclosed is the use of a local Video Random Access Memory (VRAM) interface slot to provide the ability to upgrade the graphics subsystem of a personal computer to support a multimedia daughter card. The interface is simple, requiring three control signals, three ID signals, and one connector.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 56% of the total text.

Local Video Memory Access Interface

      Disclosed is the use of a local Video Random Access Memory
(VRAM) interface slot to provide the ability to upgrade the graphics
subsystem of a personal computer to support a multimedia daughter
card.  The interface is simple, requiring three control signals,
three
ID signals, and one connector.

      Fig. 1 is a fragmentary isometric view showing the multimedia
daughter card 1 in an exploded relationship with the planar (system)
board 2 of a personal computer.  An interface connector 3, extending
upward from planar board 2, engages a mating connector 4 extending
downward from daughter card 1.  If necessary, cable connections can
be made from daughter card 1 to various adapter cards.

      Fig. 2 is a schematic diagram illustrating the logic between
the graphics controller 5, such as an SC3C928 graphics controller,
and the multimedia control signals at interface connector 3, which
provides access to the Digital to Analog Convertor (DAC) bus
interface generally reserved for only planar (system) board
components.  Multimedia IDs are provided through the MMID signals to
support a multi-function daughter card that can be attached to the
system at interface connector 3.  For example, a video memory card, a
multimedia card, or a multimedia card with video memory may be
attached.  The BREQ# signal is used to request the use of the DAC bus
interface.  The BGNT# signal is used to acknowledge this bus can be
used by the mu...