	US 7,526,349 B2
	Low power digital audio decoding/playing system for computing devices
Reginia Chan, Los Altos, Calif. (US); James Lam, Fremont, Calif. (US); William L. Densham, Los Gatos, Calif. (US); Sheau Chuen Her, Milpitas, Calif. (US); and Sterling Du, Palo Alto, Calif. (US)
Assigned to O2Micro International Limited, Grand Cayman (Cayman Islands)
Filed on Aug. 02, 2001, as Appl. No. 9/921,171.
Claims priority of provisional application 60/265466, filed on Jan. 30, 2001.
Claims priority of provisional application 60/250899, filed on Dec. 01, 2000.
Prior Publication US 2002/0068988 A1, Jun. 06, 2002
This patent is subject to a terminal disclaimer.
Int. Cl. G06F 17/00 (2006.01)

U.S. Cl. 700—94

51 Claims

1. A computer system adapted to play audio files, said computer system comprising:

a system CPU;

at least one drive coupled to said system CPU and having stored thereon an audio file comprising compressed audio data; and

circuitry coupled between said drive and a digital-to-analog converter, said circuitry also coupled to user-actuated function keys;

wherein a first operating system is adapted to control at least said system CPU and is executed when said computer system is operating in a first mode, said first operating system adapted to decompress said compressed audio data if said computer system is operated by said first operating system; and

wherein a second operating system is executed instead of said first operating system when said computer system is operating in a second mode, said second operating system adapted to decompress said compressed audio data if said computer system is operated by said second operating system, wherein decompressed audio data is transferred to said digital-to-analog converter through a first transfer path through said circuitry if said computer system is operated by said first operating system, and wherein decompressed audio data is transferred to said digital-to-analog converter through a second transfer path through said circuitry if said computer system is operated by said second operating system, wherein on said first transfer path said decompressed audio data is not modified by said circuitry but on said second transfer path play of said decompressed audio data is subject to said function keys.