Cirrus Logic Inc.

William W Chu

Thuan Thai Hoang

Rajan N Kapur

A graphics interface circuit for connecting a serial output port of a video RAM to a RAMDAC to allow a user selectable color mode to be displayed wherein the selectable color modes allows one of 256, 32K, 64K or 16.7M colors to be displayed at one time. A host microprocessor addresses the video RAM as a linear, unfragmented address space in the selected one of these modes. The invention provides an improved utilization of the video RAM memory space, as well as improved memory bandwidth as compared with prior art techniques. A graphics interface module allows for 8, 16, 24 or 32 bit wide output on the data bus from the interface to a RAMDAC. A display system of the type in which the present invention may be utilized places data generated by a host processor, after processing by a graphic displays processor into a video memory. The display processor constantly updates the video memory based upon the data generated by the host processor. The data in the video memory is transferred to a graphics interface which receives the data from the video memory and passes it to the RAMDAC which converts the digitized data into analog signals capable of being displayed by a display.

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Los Altos, CA, United States of America

William W Chu