Integrated single frame buffer memory for storing graphics and video data

In a multi-media display system for

• providing an integrated display of video, graphics and image data on a display monitor and including a source of digital image signals, a source of graphics signals, a processing unit responsive to said digital image video signals, said processing unit including an image video processing means responsive to said digital image video signals, a video capture means connected to said image video processor means and a scaling means connected to said image video processor means and to said video capture means for scaling image data of said digital image video signals,
• a display unit responsive to said digital image data signals and to graphic data signals, said display unit having means containing a stored pre-programmed color index and a graphics rasterizer means, and a three-port video random access memory structure connected to said color index and graphics rasterizer means and to said scaling means for functioning as a graphic and video buffer means, the improvement characterized in a graphics control means connected to said processing unit and said display unit for providing control signals for writing said digital image video signals into said three-port video random access memory structure and for providing control signals for writing said graphics signals into said three-port random access memory structures;
• and an input locking means connected to the output of said control means, including-logic operator means for comparing said graphics signals to said stored pre-programmed color index for providing one of two lock bits in response to said comparing function wherein said lock bit is enabled for a compare occurrence and is disabled for a non-compare occurrence,
• wherein said logic operator means of said input locking means included first, second third and fourth storage registers, said, first and second storage registers containing said pre-programmed color index data, a source color comparison means connected to the output of said graphics controller means and to the outputs of said first and second registers, and a multiplexer means connected to the outputs of said third storage register means and said source color comparison means, said source color comparison means being responsive to graphics data from said graphics controller means associated with an address being accessed and also responsive to said pre-programmed color index stored in said first and second storage-registers for providing a 1 bit for a compare and a 0 bit for a non-compare, said fourth storage register being connected to said multiplexer means for providing inband and outband mode signals to said multiplexer for setting and resetting said lock bits.