51单片机中用定时器怎么样控制频率答:include<intrins.h> define uint unsigned int //宏定义 define uchar unsigned char //宏定义 sbit beep=P2^3;uchar num=0,times=0;uint flag,tt;uint freq[]={4000,400,80,40,20,10,5,4}; //1Hz~1KHz void main() //主函数 { beep=0;TMOD=0x12;//设置定时器0,定时器...