Audio-only combined DVD and CD player

An audio DVD-CD device, comprising:

• a playback system for playing audio from either a CD disc or a DVD disc depending on which type of disc is inserted at a given moment;
• a data manager located within said playback system;
• and
• a user-accessible button panel and an on screen display both electronically connected to said playback system, for duplicating the functionality of a DVD selection panel so as to enable a user to make playback selections native to the DVD content that would normally be selectable from a display of a DVD player except that no such display exists and no video portion of the DVD is displayed;
• a data bus;
• a disc motor for rotating the disc, responsive to signals sent along the bus,
• an optical pickup (OPU) subsystem, for obtaining data from the disc;
• and
• a signal amplifier, servo error detector, servo control subsystem, and a plurality of servo drivers, all connected to the disc motor,
• wherein the disc motor includes two or more spindle motors which rotate the disc to a variety of desired speeds depending on whether a CD or DVD is being operated, various user selections, and internal resistance factors,
• wherein the servo drivers output signals to disc motor to drive and control the rate of rotations of the various motors contained in disc motor, where the servo drivers also output signals to position the OPU on the desired location of the disc to focus the laser beam onto disc and to track the recorded spiral pits on disc;
• and further wherein the bus has an arbitrator and devices connected thereto make bus access requests of the arbitrator prior to obtaining access, where each access request is typically processed according to a priority scheme, which is typically based on the priority given to a specific device and the order in which the bus access requests are received;
• wherein the priority scheme is set up so that no device monopolizes the bus, thereby avoiding the starving of the other devices;
• and further wherein the arbitrator has a queuing module designed to share the bus so that no device attached therein uses more than approximately 40% of the bus's total available bandwidth;
• wherein the various components of the playback system are either located on one integrated circuit die or are separate non-integrated components in any combination;
• wherein the playback system accepts data from pre-fabricated CD/DVD modules that already have all the logic for sensing data from the disc lenses, motors, and optical devices, so that the OPU, motor, error detector, and control subsystem are unused and instead the disc lenses, motors, and optical devices are connected directly to the pre-fabricated disc sensing mechanisms.