Low-power cd-rom player with cd-rom subsystem for portable computer capable of playing audio cds without supply energy to cpu

Abstract

A low-power audio CD player for portable computers permits operation of the CD-ROM subsystem when power is not being supplied to the computer subsystem. In one embodiment of the invention, the computer subsystem comprises a system CPU, a digital-audio generating circuit, a digital computer bus coupling the CPU and the digital-audio generator circuit, and a digital computer bus controller. The CD audio subsystem comprises an audio device capable of playing an audio CD and coupled to the digital computer bus controller, an audio amplifier circuit coupled to the audio device, and an audio interface coupled to the digital computer bus in parallel to the digital computer bus controller and the audio device. The audio interface is adapted to generate signals to operate the audio device and play the audio CD when power is not being supplied to the computer subsystem or to the CPU. In method form, a method for playing an audio CD in a computer system comprises deenergizing a computer CPU; and controlling, using an audio interface coupled to a digital computer bus in parallel to a digital computer bus controller and an audio device capable of playing an audio CD, the audio device and a computer audio amplifier to play an audio CD without supplying energy to the CPU.