Abstract: A media processing system and device with improved power usage characteristics, improved audio functionality and improved media security is provided. Embodiments of the media processing system include an audio processing subsystem that operates independently of the host processor for long periods of time, allowing the host processor to enter a low power state while the audio data is being processed. Other aspects of the media processing system provide for enhanced audio effects such as mixing stored audio samples into real-time telephone audio. Still other aspects of the media processing system provide for improved media security due to the isolation of decrypted audio data from the host processor.

Abstract: An apparatus including a system bus coupled to an I/O interface which includes a pointer register and a rejecting circuit which determines whether a write to the pointer register will be accepted or rejected. The I/O interface is further coupled to at least one I/O bus having at least one I/O device connected thereto. The system bus is further coupled to a main memory and to a Central Processing Unit (CPU) which is capable of executing software instructions, providing a command structure corresponding to an access of an I/O device, and writing to the pointer register an address of a location in main memory of the command structure. The CPU further includes a hardware indicator responsive to the rejecting circuit for providing a status signal indicating the status of a write to the pointer register. The CPU executes the software in accordance with the status signal. The apparatus allows the software being executed by the CPU to software pend accesses to devices not directly connected to the system bus.