US 5,334,998 A · Method and apparatus for utilizing blanking on both zero setup and pedestal setup display monitors with a conventional computer system

Abstract

In a computer system having a frame buffer, apparatus for providing an overlay for the frame buffer, and a digital-to-analog converter for furnishing analog signals from the frame buffer to a pedestal setup display monitor, the digital-to-analog converter including apparatus for furnishing a blank level substantially below the lowest level of the analog signal desired to be visible on the monitor during retrace periods when used with a pedestal setup display monitor, the improvement including apparatus for allowing the system to utilize zero setup display monitors including apparatus for disabling the apparatus for furnishing a blank level when the computer system is used with a zero setup display monitor, and apparatus for causing the apparatus for providing an overlay for the frame buffer to furnish signals indicating a black level during retrace periods when the computer system is used with a zero setup display monitor.

Claims14

Dependent claims

In a computer system having a frame buffer, means for providing an overlay for the frame buffer, a digital-to analog converter for furnishing analog signals from the frame buffer to a pedestal setup display monitor, and means for furnishing a blank level at a level substantially below the lowest level of the analog signal desired to be visible on the monitor during retrace periods when used with a pedestal setup display monitor, the improvement comprising apparatus for allowing the system to utilize zero setup display monitors, said apparatus comprising means for disabling the means for furnishing a blank level when the computer system is used with a zero setup display monitor, and means for causing the means for providing an overlay for the frame buffer to furnish signals indicating a black level during retrace periods when the computer system is used with a zero setup display monitor.

A computer system capable of providing appropriate analog outputs to both a zero-setup display monitor and a pedestal setup display monitor comprising:

a digital-to-analog converter (DAC) including means for receiving a first plurality of digital signals, means for receiving a second plurality of digital signals, and means for outputting analog signals;
frame buffer means coupled to said means for receiving a first plurality of digital signals;
frame buffer overlay means coupled to said means for receiving a second plurality of digital signals;
circuit means for generating a black level signal coupled to said frame buffer overlay and said means for receiving a second plurality of digital signals;
means for switchably coupling a blanking signal to either said DAC or said circuit means for generating a black level;
wherein, in the event said computer system is used with a pedestal setup display monitor, said means for switchably coupling a blanking signal couples said blanking signal to said DAC, thereby causing said DAC to output an analog signal appropriate for said pedestal setup display monitor,
wherein, in the event said computer system is used with a zero setup display monitor, said means for switchably coupling a blanking signal couples said blanking signal to said circuit means for generating a black level signal, causing said circuit means to couple said black level signal to said DAC, thereby causing said DAC to output an analog signal appropriate for said zero setup display monitor.

4 more elements

Dependencies are inferred from the claim text.

Method and apparatus for utilizing blanking on both zero setup and pedestal setup display monitors with a conventional computer system

Life of this patent

Method and apparatus for utilizing blanking on both zero setup and pedestal setup display monitors with a conventional computer system

Life of this patent

Abstract

Claims14