哪位大哥能帮我看下 下面这程序是怎么运行的?

小二黑

功能是用AM发射莫斯码  然后用收音机能听到。

void setup(){

DDRD=B00000100; //Set pin 2 to an

}

void loop(){

for(unsigned int x=0;x<500;x++)

{

for (unsigned int y=0; y<800;y++){

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=4;

}

delay(1);

}

delay(1000);

for(unsigned int z=0;z<200;z++){

  for (unsigned int k=0; k<800;k++){

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=4;

}

delay(2);

}

delay(1000);

for(unsigned int f=0;f<200;f++){

  for (unsigned int r=0; r<800;r++){

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=0;

PORTD=4;

}

delay(1);

}

delay(1000);

}

奈何col

通过拉高拉低IO口来发送信号，每个PORTD=0，会占用一定的时钟周期，相当于delay某个时间