OV511+ based on OV511, is a low cost and highly integrated solution for USB PC camera applications. It remains OV511’s performance unchanged or is improved, while some new features were implemented. New features include built-in USB transceiver with selectable external USB transceiver interface, more effective packet size of the isochronous pipe, programmable LED control, programmable switching power clock with frequencies of 24K/48K/96K/192KHz, etc. OV511+ is a USB PC camera controller that includes a proprietary compression engine supporting real time image transfer through USB bus. A complete USB camera system consists of OV511+, a 256Kx16 EDO DRAM, and a digital camera such as OV7620 for VGA resolution or OV6620 for CIF resolution. Camera Interface generates different image formats by taking either 16-bit YUV 4:2:2/RGB raw data or 8-bit Y 4:0:0/RGB raw data inputs. OmniCE is the proprietary compression engine. It not only performs 10~15fps for VGA and 30fps for CIF, but also allows very fast decompression with low CPU utilization. Depending on the camera device that is built with the system, either SCCB or Parallel IO bus can be chosen. The SCCB bus master uses two dedicated pins “SIO-0” & “SIO-1”, while the PIO shares with Y & UV buses. Snapshot button allows users to take a high quality, VGA resolution uncompressed still image The functional blocks of OV511+, as shown in the following figure, consist of Camera Interface, DRAM Interface, OmniCE, UDC interface, ISO FIFO, System Control, SCCB and PIO.