The device is based on an ARM946E-S microprocessor whose function is to control the entire system, to capture and play back audio, and to multiplex compressed video and audio into a single bitstream that can be delivered to the main CPU. Most computationally-intensive functions are implemented in hardware which can be programmed according to user specifications, thus allowing the ARM® processor to be free for other user-defined functions such as advanced image and multimedia processing. The processor has 8 KB + 8 KB of internal instruction/data cache which helps it to operate efficiently and use minimal DDR SDRAM bandwidth.