Abstract: An data processing apparatus for a digital versatile disk ROM system includes an EFM demodulator, an error-correction decoder, and a data transfer unit, each of which is interfaced with an external memory partitioned into first, second, and third banks for storing demodulated data, error-corrected data and transfer data. A bank pointer comparator generates first, second, and third bank pointers, compares the bank pointers with each other, and activates or deactivates predetermined enable signals in accordance with comparison result. The bank pointers represent the bank of external memory in which EFM-demodulated data is written, the bank in which error-corrected data is stored, and the bank from which transfer data is read, respectively. Each bank pointer is incremented when an operation associated with the bank pointer is completed rather than the conventional technique of increasing the bank pointer whenever an ECC block sync signal is input.

Abstract: In an ATAPI device and method for interfacing a digital video disk signal processor with a data processor, a digital video disk ROM interfacing apparatus controls data transmission from the digital video disk signal processor to the ATAPI interfacing apparatus such that a plurality of bytes of data are transmitted for each data transmission request. In the digital video disk ROM interfacing apparatus, a byte designator stores a number of designated units which is the number of data units which are to be transmitted once. A counter up-counts when a data unit is transmitted and outputs a number of transmitted units. A comparator compares the number of designated units output by the byte designation means with the number of transmission units output by the counter. A data request signal generator requests data transmission to the digital video disk signal processor according to a comparison result from the comparator.