| 摘要 |
PURPOSE:To enable efficient memory access by normally allowing a control part to access a memory and also allowing a sound source part to access the memory for the read time of data for musical sound generation when the sound source part sends a use request signal. CONSTITUTION:The ROM 18 as an external memory is stored with the data for musical sound generation and data for operation control data and a CPU 15 reads a program out of the ROM 18 and controls the operations of respective circuit devices. An access control part 25 control an external memory bus 17 so as to enable one of the CPU 15 and sound source part 14 to access, and normally the CPU 15 preferentially accesses the ROM 18. When the sound source 14 needs to read waveform sample data out of the ROM 18, the use request signal is generated and the access control part 25 when supplied with this use request signal allows the sound source 14 to access the ROM 18 only for the time required to read out the waveform sample data. |
