Question

51单片机控制DAC0832产生正弦波，如何用定时器改变频率，求代码!

#include <reg51.h>
unsigned int i;
code unsigned char Sin[128]={
64,67,70,73,76,79,82,85,88,91,94,96,99,102,104,106,
109,111,113,115,117,118,120,121,123,124,125,126,126,
127,127,127,127,127,127,127,126,126,125,124,123,121,
120,118,117,115,113,111,109,106,104,102,99,96,94,91,
88,85,82,79,76,73,70,67,64,60,57,54,51,48,45,42,39,
36,33,31,28,25,23,21,18,16,14,12,10,9,7,6,4,3,2,1,
1,0,0,0,0,0,0,0,1,1,2,3,4,6,7,9,10,12,14,16,18,21,23,
25,28,31,33,36,39,42,45,48,51,54,57,60};
main()
{
while(1)
{
i++;
if(i==128)i=0;
P1=Sin[i];
}
}

Answer 1

你确定是使用定时器改变频率？？
下面的程序是使用定时器改变幅值的，你要是确定是定时器改变频率的话，把具体的要求贴出来
#include <reg51.h>
unsigned int i;
code unsigned char Sin[128]={
64,67,70,73,76,79,82,85,88,91,94,96,99,102,104,106,
109,111,113,115,117,118,120,121,123,124,125,126,126,
127,127,127,127,127,127,127,126,126,125,124,123,121,
120,118,117,115,113,111,109,106,104,102,99,96,94,91,
88,85,82,79,76,73,70,67,64,60,57,54,51,48,45,42,39,
36,33,31,28,25,23,21,18,16,14,12,10,9,7,6,4,3,2,1,
1,0,0,0,0,0,0,0,1,1,2,3,4,6,7,9,10,12,14,16,18,21,23,
25,28,31,33,36,39,42,45,48,51,54,57,60};
main()
{
TMOD=0X01;
EA=1;
ET0=1;
TR0=1;
TH0=(65535-1000)/256;
TL0=(65535-1000)%256;
while(1)
{
P1=Sin[i];
}
}
void timer0(void) interrupt 1
{
TH0=(65535-1000)/256;
TL0=(65535-1000)%256;
i=i+1;
if(i==128)i=0;
}

Answer 2

详见DDS频率合成技术

Answer 3

你可以通过按键改变进入中断定时的参数改变周期嘛。。。