Automatic virtual display panning circuit for providing VGA display data to a lower resolution display and method therefor

摘要

A circuit and method for providing VGA display data to a display of lower resolution, such as an LCD panel, is disclosed. The circuit detects a write to the Frame Buffer that stores the full resolution VGA image, determines the address within the Frame Buffer that was changed, then translates the Start Address of the circuit such that the recently updated data will be displayed at or near the center row of the display. The circuit blocks accesses to display data outside the range of data displayed on the lower resolution display such that the operation of the circuit is transparent to a conventional VGA controller, thereby providing automatic virtual display panning for VGA data that is displayed on a lower resolution display such as an LCD panel.