| 摘要 |
PROBLEM TO BE SOLVED: To make the device usable for electronic musical instruments with various performance and suppress a decrease in the quality of a musical sound generated by a sound source part by providing a clock generating means which make the ratio of both the frequencies of a 1st and a 2nd operation clock signal between a 1st and a 2nd mode. SOLUTION: A clock generator 109 generates a master clock corresponding to the frequency of crystal 8, properly divides its frequency, and supplies operation clocks to respective parts in a sound source chip 1. Here, ϕTG is an operation clock supplied to the sound source part 104 and ϕCPU is an operation clock supplied to a CPU 102. According to the switching state of a switching part (SX) 9, the frequency ratio of ϕTG and ϕCPU is varied to vary the ratio of the possible frequency of access to an external memory 2 by the CPU 10 per unit time and the possible frequency of access to the external memory 2 by the sound source part 104. Further, the time-length ratio of a CPU access section and a sound source access section is made variable. |
