Patent ID: 6366971
Filing Date: 2002-04-02
Classification: G06F,G10H

Abstract:
A waveform playback apparatus comprising:a CPU that controls the apparatus as a whole; a memory that stores a plurality of waveform data to be played back by a plurality of channels; a buffer memory that stores waveform data of plural samples with respect to each of the plurality of channels; a digital audio circuit that inputs the waveform data of the plurality of channels in a sampling period; a bus having a burst transfer function; a first transfer circuit that transfers the waveform data stored in the memory to the buffer memory via the bus with respect to each of the channels; a second transfer circuit that reads the waveform data from the buffer memory by each of the plural samples in each sampling period with respect to each of the channels independently, so that the second transfer circuit transfers the read waveform data to the digital audio circuit; wherein the buffer memory stores a part of the waveform data stored in the memory with respect to each of the channels, and wherein when the second transfer circuit starts data transfer for a single specific channel, the first transfer circuit performs burst transfer, using units of plural samples, on a top portion of the waveform data to the buffer memory, and after the second transfer circuit starts the data transfer for the single specific channel, the first transfer circuit performs burst transfer, using units of plural samples, on following waveform data following the waveform data which have been already transferred to the buffer memory if a prescribed vacant area is created in the buffer memory due to the data transfer performed by the second transfer circuit.