| 摘要 |
<P>PROBLEM TO BE SOLVED: To make a separate excitation buzzer emit a plurality of timbres even when only a single PWM signal output port is used. <P>SOLUTION: The sound generating device is provided with: a chime sound generating circuit 2 which performs ON/OFF control over supply of a current to a separate excitation buzzer 6 while gradually attenuating the PWM signal; a chime sound inhibiting circuit 3 which inhibits the current from being supplied to the separate excitation buzzer 6 by the chime sound generating circuit 2 by stopping the supply of the PWM signal; a buzzer sound generating circuit 4 which performs ON/OFF control over the supply of the current to the separate excitation buzzer 6 according to the PWM signal, and a buzzer sound inhibiting circuit 5 which inhibits the current from being supplied to the separate excitation buzzer 6 by the buzzer sound generating circuit 4 by stopping the supply of the PWM signal. A microcomputer 1 supplies the same PWM signal to the chime sound generating circuit 2 and buzzer sound generating circuit 4 to perform control for generating a buzzer sound by driving the chime sound inhibiting circuit 3 or control for generating a chime sound by driving the buzzer sound inhibiting circuit 5. <P>COPYRIGHT: (C)2004,JPO |
