Question

用单片机控制蜂鸣器放音乐

下面的程序怎么理解，数组是怎么得到的
#include "reg51.h"

unsigned char Count;

sbit FMQ =P3^5 ; //蜂鸣器控制脚

unsigned char code SONG[] ={

0x26,0x20,0x20,0x20,0x20,0x20,0x26,0x10,0x20,0x10,0x20,0x80,
0x26,0x20,0x30,0x20,0x30,0x20,0x39,0x10,0x30,0x10,0x30,0x80,
0x26,0x20,0x20,0x20,0x20,0x20,0x1c,0x20,0x20,0x80,0x2b,0x20,
0x26,0x20,0x20,0x20,0x2b,0x10,0x26,0x10,0x2b,0x80,0x26,0x20,
0x30,0x20,0x30,0x20,0x39,0x10,0x26,0x10,0x26,0x60,0x40,0x10,
0x39,0x10,0x26,0x20,0x30,0x20,0x30,0x20,0x39,0x10,0x26,0x10,
0x26,0x80,0x26,0x20,0x2b,0x10,0x2b,0x10,0x2b,0x20,0x30,0x10,
0x39,0x10,0x26,0x10,0x2b,0x10,0x2b,0x20,0x2b,0x40,0x40,0x20,
0x20,0x10,0x20,0x10,0x2b,0x10,0x26,0x30,0x30,0x80,0x18,0x20,
0x18,0x20,0x26,0x20,0x20,0x20,0x20,0x40,0x26,0x20,0x2b,0x20,
0x30,0x20,0x30,0x20,0x1c,0x20,0x20,0x20,0x20,0x80,0x1c,0x20,
0x1c,0x20,0x1c,0x20,0x30,0x20,0x30,0x60,0x39,0x10,0x30,

0x10,0x20,0x20,0x2b,0x10,0x26,0x10,0x2b,0x10,0x26,0x10,0x26,
0x10,0x2b,0x10,0x2b,0x80,0x18,0x20,0x18,0x20,0x26,0x20,0x20,
0x20,0x20,0x60,0x26,0x10,0x2b,0x20,0x30,0x20,0x30,0x20,0x1c,
0x20,0x20,0x20,0x20,0x80,0x26,0x20,0x30,0x10,0x30,0x10,0x30,
0x20,0x39,0x20,0x26,0x10,0x2b,0x10,0x2b,0x20,0x2b,0x40,0x40,
0x10,0x40,0x10,0x20,0x10,

0x20,0x10,0x2b,0x10,0x26,0x30,0x30,0x80,0x00,};

void Time0_Init() //定时器0初始化函数

{

TMOD = 0x01; //工作模式选择

IE = 0x82; //中断设置

TH0 = 0xD8; //装初值

TL0 = 0xEF; //12MZ晶振，10ms

}

void Time0_Int() interrupt 1 //定时器0中断子函数

{

TH0 = 0xD8;

TL0 = 0xEF;

Count++; //长度加1

}

void Play_Song(unsigned char i)

{

unsigned char Temp1,Temp2;

unsigned int Addr;

Count = 0; //中断计数器清0

Addr = i * 217;

while(1)

{

Temp1 = SONG[Addr++];

if ( Temp1 == 0xFF ) //休止符

{

TR0 = 0;

Delay_xMs(100);

}

else if ( Temp1 == 0x00 ) //歌曲结束符

{

return;

}

else

{

Temp2 = SONG[Addr++];

TR0 = 1;

while(1)

{

FMQ = ~FMQ;

Delay_xMs(Temp1);

if ( Temp2 == Count )

{

Count = 0;

break;

}

}

}

}

}
谢谢你，我已经自己编出来了，恩，你说的问题确实是延时定义有问题。

Answer 1

看起来数组应该是音乐数据，其中包括四种数据，就是休止符（每个100毫秒）、歌曲结束符、音阶（给出的是蜂鸣器的震荡周期）、一个音阶持续的时间长度。如果你的晶振是12MHz，按照定时器中断给Count加一来看，音阶持续的时间应该是以10毫秒为单位。
Play_Song函数要求给出参数i，我的看法是这个i是指要播放第几段乐曲，i*217表示每段乐曲都是217个字节。本例中，数组只给出217个字节，所以只有一段乐曲，播放时需要给出参数i=0.

if ( Temp1 == 0xFF ) //休止符
{
TR0 = 0;
Delay_xMs(100);
}
所以休止符每个固定是100毫秒。
如果读到第一个不是休止符或者结束符的字节，那就是音阶，而下一个字节就是这个音阶的长度或者说节拍

while(1)
{
FMQ = ~FMQ;
Delay_xMs(Temp1);
if ( Temp2 == Count )
{
Count = 0;
break;
}
}
这一段是说，如果当前音阶的时间（Temp2次定时器中断，由Count计时）还没完，就每隔Temp1毫秒震动一次蜂鸣器，就形成一个震动频率，这段时间就发出一定音调的乐音。不过我也有疑惑，震荡周期如果以毫秒为单位恐怕只能发出次声波，所以以上对有关Delay_xMs函数时间的估算都可能有问题，还得看Delay_xMs函数的具体定义才行。