Abstract: A single chip audio system 100 includes a bus interface 101, digital to analog converters 110, an analog mixer 115, and analog spatial enhancement circuitry 7500. Digital to analog converters 110 convert digital audio data received through bus interface 101 into analog signals. Analog mixer 115 mixes signals received from digital to analog converters 110 with an analog signal received from an external source. Analog spatial enhancement circuitry 7500 enhances first and second mixed analog signals output from analog mixer 115.

Abstract: A system 100 fabricated on a single integrated circuit chip includes a microprocessor 101 operating from a high speed bus 102 and a peripheral bus 103 operating in conjunction with high speed bus 102 through a bus bridge 113. A first set of processing resources operate from high speed bus 102 and includes an external memory interface 108, a direct memory access engine 105 for controlling the exchange of information through memory interface 108, and a boot memory 104 for storing boot code. A second set of processing resources operate from peripheral bus 103 and includes an interrupt controller 115 for issuing interrupt requests to microprocessor 101, a set of programmable timers 117 for generating timed interrupt signals, and a phase locked loop 131 for generating timing signals.

Abstract: An audio system 100 includes circuitry 116 for generating an audio data stream and circuitry 103 for generating digital words defining a volume control level. System 100 also includes volume control circuitry 5000 for controlling the amplitude of the audio data stream in response to the digital words. Volume control circuitry 5000 includes a master register 5001 for holding digital words received from circuitry for generating 116 and a slave register 5002 for holding a digital word selectively transferred from master register 5001 in response to an enable signal. Output control circuitry 5005, 5006 and 5007 receive the audio data stream and apply a preselected gain defined by the digital word held in slave register 5002. Volume control circuitry 5000 also includes circuitry 5003, 5004 for generating the enable signal when a digital word held in the master register 5001 changes and the audio data stream output from ouput control circuitry 5005, 5006, 5007 reaches a zero crossing.

Abstract: Amplitude control circuitry 5000 includes a first register 5001 for storing received amplitude control data and a second register 5002 for storing amplitude control data transfered from first register 5001. Output circuitry 5005, 5006, 5007 controls the amplitude of a received signal in response to amplitude data transferred from second register. A sensor 5003 determines when data stored in first register 5001 and second register 5002 does not match and enables a comparator 5004 when data in first register 5001 and, second register 5002 does not match. Comparator 5004 compares a signal output from output circuitry 5005, 5006, 5007 with a reference signal and generates a signal for enabling the transfer of data from first register 5001 to second register 5002 when the signal output from output circuitry 5005, 5006, 5007 falls within a window defined by the reference voltage.

Abstract: A single chip audio system 100 includes a bus interface 101, digital to analog converters 110, an analog mixer 115, and analog spatial enhancement circuitry 7500. Digital to analog converters 110 convert digital audio data received through bus interface 101 into analog signals. Analog mixer 115 mixes signals received from digital to analog converters 110 with an analog signal received from an external source. Analog spatial enhancement circuitry 7500 enhances first and second mixed analog signals output from analog mixer 115.

Abstract: An audio system 100 disposed on a single chip includes an output mixer 115 having inputs for receiving first digital audio data of a first bit width from a first digital-to-analog converter 110, digital audio data of a second bit width from a second digital-to-analog converter 6601, and analog data from an external port. An output port drives an analog signal output from the output mixer. An input mixer 114 has inputs for receiving analog data from a plurality of sources and analog-to-digital converters 111 to convert an analog output from the input mixer into digital data. An input path transmits the digital data output from the analog to digital convertors 111 to an external digital bus.