CD-ROM decoder having means for reading selected data from a CD into a memory

Abstract

A CD-ROM decoder comprising a DSP interface, an error correcting portion or a RAM access portion, a host interface, and a subcode reading portion. A control microcomputer and a buffer RAM are connected to the CD-ROM decoder. The DSP interface subjects CD-ROM data to a descrambling processing and writes it into the buffer RAM. After code errors of the CD-ROM data written into the buffer RAM are corrected, the CD-ROM data is output from the host interface to a host computer. The subcode reading portion reads subcode data for 98 frames and writes it into the buffer RAM. The subcode data is output from the host interface to the host computer. The subcode data is transferred not through the control microcomputer but directly to the host computer. Alternatively, the RAM access portion reads selected CD-ROM data from the host interface into the buffer RAM. As a result, the load applied to the control microcomputer for controlling the operation of the CD-ROM decoder is reduced.

Dependencies are inferred from the claim text.