#include<reg52.h>
#define uInt unsigned int
#define uchar unsigned char
uchar t_max = 10; //一個周期
static uchar t = 0,i = 0; //PWM計數(shù)
/*
uchar code SinParam[40]={
0,3,6,9,13,16,19,22,25,28,31,34,37,40,43,45,
48,51,54,56,59,61,64,66,68,71,73,75,77,79,81,83,
84,86,88,89,90,92,93,94,95,96,97,98,98,99,99,100,
100,100,100,100,100,100,99,99,98,98,97,96,95,94,93,92,
90,89,88,86,84,83,81,79,77,75,73,71,68,66,64,61,
59,56,54,51,48,45,43,40,37,34,31,28,25,22,19,16,
13,9,6,3
};
*/
uchar code SinParam[20]={
5,5,6,7,7,8,9,9,9,9,10,9,9,9,9,8,
7,7,6,5
};
// 200點正弦波樣本值
void main(void)
{
TMOD = 0x02; //定時器0，工作模式2，8位定時模式
TH0 = 146; //寫入預(yù)置初值（取值1-255，數(shù)越大PWM頻率越高）
TL0 = 146; //寫入預(yù)置值（取值1-255，數(shù)越大PWM頻率越高）
TR0 = 1; //啟動定時器
ET0 = 1; //允許定時器0中斷
EA = 1; //允許總中斷
P2 = 0xff; //初始化P1
while(1)
{
;
}
}
timer0()interrupt 1 using 2
{
t++; //每次定時器溢出加1
if(t < t_max && t >= SinParam[i]) //PWM周期 5
{
P2 = 0x00; //使LED燈亮
}
else if( t >= t_max)
{
t = 0; //使t=0，開始新的PWM周期
i++;
P2 = 0xff;
}
if(i >= 20) i = 0;
}
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