System and method for frame buffer storage and retrieval in alternating orientations

Abstract

The present invention provides a method and apparatus for storing image data for successive frames in a frame buffer. Specifically, the method and apparatus allow for a display-sized frame buffer to be utilized where a host system provides image data in a format different from that which the display requires to be written to it while retaining the beneficial aspects of concurrent read and write operations from and to the frame buffer. Using this method a buffer controller receives image data from a host system in a first format (e.g. row-by-row) and writes it to the frame buffer in the first format. When the buffer is completely filled with the first frame, it is read out in a second format (e.g. column-by-column) by the buffer controller and provided to a display driver that writes the data to the display. As the first frame is read out in the second format, the buffer controller receives image data for a second frame from the host system in the first format, but rotates it before writing it to the frame buffer such that it is written to the frame buffer in the second format. This rotation allows the buffer controller to write to the frame buffer and the display driver to read from the frame buffer concurrently, despite the different image data format requirements of the host system and display. When the second frame is completely written to the buffer in the second format, the buffer controller then reads the buffer in the first format, and writes it to the display. At this point the process repeats. Thus, the benefits of concurrent read and write are preserved.