Integrated apparatus for displaying a plurality of modes of color information on a computer output display

An apparatus for providing digital shade values for display on a display device for a data processing system, the apparatus comprising:

• a color index map to contain digital shade values, said color index map being configured to translate pixel data received from a frame buffer to one or more of the digital shade values during an active scan period of the display device;
• a FIFO buffer coupled to said color index map, said FIFO buffer being configured to receive updated digital shade values from the data processing system during the active scan period and to transfer the updated digital shade values to said color index map during a retrace interval of the display device;
• a gamma correction map coupled to said color index map and to said FIFO buffer, said gamma correction map being configured to receive digital shade values from said color index map and translate the digital shade values into corrected digital shade values during the active scan period;
• and
• wherein said FIFO buffer is further configured to receive updated corrected digital shade values from the data processing system during the active scan period and to transfer the updated corrected digital shade values to said gamma correction map.

An apparatus for providing digital shade values for display comprising:

• a frame buffer to store image data received from a host processor, the image data representing at least a portion of an image;
• color index map circuitry to output a sequence of digital shade values indicated by the image data stored in the frame buffer, the color index map circuitry being configured to store in an update operation updated digital shade values received from the host processor;
• and
• a FIFO buffer to receive from the color index map circuitry the sequence of digital shade values and to output each digital shade value of the sequence of digital shade values for display at a respective location on a display device during the update operation to prevent display of incorrect digital shade values while updated digital shade values are stored in the color index map circuitry.

A method for updating a color index map in a display device of a data processing system, the method comprising the steps of:

• a FIFO buffer receiving a plurality of digital shade values from the data processing system during an active scan period;
• transferring the plurality of digital shade values from the FIFO buffer to the color index map during a retrace interval of the display device;
• detecting the FIFO buffer is full;
• and
• transferring the plurality of digital shade values to the color index map during the active scan period in response to detecting the FIFO buffer is full.