Camera interface and method using dma unit to flip or rotate a digital image

Abstract

A camera interface employing a direct memory access (DMA) unit to digitally perform an image transformation such as 'flipping' and 'rotating' an image (e.g., to correct for X-axis, Y-axis, or XY-axes mirroring). The image transforming DMA unit includes an address generator and a data selector. The address generator appropriately modifies a frame start address, a burst transfer address, a line start address, of an image frame, based on the X, Y, or XY mirrored image mode. The data selector changes the sequences of words and of pixels in a word based upon the mirrored image mode. The data selector includes a plurality of pixel-sequence modifying multiplexers each for selecting between a word having an original pixel sequence stored in the buffer memory and a word having the reverse pixel sequence; and a word-sequence modifying multiplexer outputting the selected words in the original word sequence or in the reverse word sequence in response to outputs of a counter that increments or decrements based upon the mirrored image mode.