1 实验原理
PWM(Pulse Width Modulation)脉冲宽度调制,一种用数字信号控制模拟量的方法,因此在控制领域应用非常广泛。所谓PWM信号就是调整波形的占空比得到一系列矩形脉冲。PWM信号产生的原理是基于面积等效原理。即冲量相同的形状不同的窄脉冲加在具有惯性的环节上时,其效果基本相同。
2 参考程序
#include
sbit LED=P2^0;
void Delay(unsigned int i)
{
while(i--);
}
void main()
{
unsigned char Time,i;
while(1)
{
for(Time=0;Time<100;Time++) //改变亮灭时间,由暗到亮
{
for(i=0;i<20;i++) //计次延时
{
LED=0; //LED亮
Delay(Time); //延时Time
LED=1; //LED灭
Delay(100-Time); //延时100-Time
}
}
for(Time=100;Time>0;Time--) //改变亮灭时间,由亮到暗
{
for(i=0;i<20;i++) //计次延时
{
LED=0; //LED亮
Delay(Time); //延时Time
LED=1; //LED灭
Delay(100-Time); //延时100-Time
}
}
}
}
3 参考资料
(1)https://www.bilibili.com/video/BV1VJ411b7Wi/?spm_id_from=333.880.my_history.page.click;
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