Methods and apparatus for delayed block release in compact disc systems

Abstract

Disclosed is a disc drive system that includes a digital signal processor for processing information sectors read from a CD media. The digital signal processor is configured to parse the information sectors into data frames and subcode frames. A data auto-start unit for triggering a data transfer to a buffer memory when a desired data frame is detected. A subcode auto-start unit for triggering a subcode transfer to the buffer memory when a desired subcode frame is detected. Preferably, the desired data frame and the desired subcode frame have a same MSF. The disc drive system further includes a buffer manager having a plurality of counters that are configured to track the number of data frames and the number of subcode frames being transferred to the buffer memory, and releasing a block including one of the data frames and one of the subcode frames when the counters indicate that the block is complete.

Description

[0001] This application is related to the following US patent applications: (1) Ser. No. _______ (attorney docket no. ADAP019) filed on the same day as the instant application, and entitled "Methods and Apparatus For Compact Disc Automatic Start", and (2) Ser. No. ______ (attorney docket no. ADAP021) filed on the same day as the instant application, and entitled "Method and Apparatus for Subcode / Data Synchronization in a Compact Disc System". These applications are hereby incorporated by reference.[0002] 1. Field of the Invention[0003] This invention relates generally to compact discs, and more particularly efficient integrated circuit processing of sector components in high speed compact disc drives.[0004] 2. Description of the Related Art[0005] Compact disc drives have become increasingly popular due to their ability to rapidly access large quantities of data as well as provide fine quality digital play-back. To meet the need for increased data transfer rates, compact disc "CD" ha...

AI Technical Summary

Problems solved by technology

A common technique for increasing processing speeds has been to incorporate faster microprocessors, however, even fast processors have found reading and processing the CD media being spun at ever increasing speeds a challenge.

By way of example, basic CD drive tasks, such as "seeking" to a location on the CD media in order to start play-back, are becoming increasingly difficult.

In some cases, the microprocessor that is in charge of seeking to a particular "start" location on a CD media track has been found to be too slow to begin a play-back once the start location has been identified.

As mentioned earlier, as disc speeds continue to increase, the microprocessors that are assigned the task of processing the 98 bytes of subcode for each sector 102, will find it challenging, if not impossible, to begin the data transfer before the next sector is encountered.

However, even the fastest of microprocessors will experience that processing and finding the correct subcode MSF, and triggering a start after the correct subcode MSF is actually found is difficult without introducing delays.

Unfortunately, these components are often times released from a holding buffer memory with offsets.

Consequently, if the subcode component is released before the data component, the data that is designed to interact with the subcode graphics will not match up.

This problem is sometimes further complicated when offsets of several frames are produced, which may introduced play-back errors or degrade the quality of the data being read.

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