单片机无源蜂鸣器的程序，请求解释下这个程序从第一个for开始的意思！

#include//包含51的头文件

sbit BEEP=P1^5//sbit是位定义的意思，即使用beep来代表单片P1端口的第5个IO口

void beep()//蜂鸣器子函数，方便调用，

{

unsigned char i , j//设置无符号字符型变量i；和J

for (i=0i<100i++)//定义一个for循环，每次完整地执行for里面的所有语句，i就自增1，直到i=10

{ //当i=100是，for循环就结束

BEEP=!BEEP//BEEP取反//蜂鸣器发生原理，进行电平取反，散蔽滚冲余原来为高电平，下一次执行就变成低电平

for (j = 0 j<200 j++)//需要产生方波这个是延时程序

}

BEEP=1//关闭蜂鸣器蜂鸣器电平不并段发生变化的时候，蜂鸣器无法发声。

}

将51单片机的P1.2口连接到蜂鸣器的一个管脚上，另外一个管脚接地。若声音腔历慧小，则添加一个三级管放大电路或直接串一个UL2003

/*------------------------------------------------*/

#include<reg52.h> //包含头文件，一般情况不需要改动?

//头文件包含特殊伍答功能寄存器的定义

/*------------------------------------------------

硬件端口定义

------------------------------------------------*/

sbit SPK=P1^2 //定义音乐输出端口

unsigned char Timer0_H,Timer0_L,Time

//世上只有妈妈好数据表

code unsigned char MUSIC[]={ 6,2,3,5,2,1, 3,2,2,5,2,2,1,3,2,6,2,1,5,2,1,

6,2,4, 3,2,2, 5,2,1,6,2,1,5,2,2, 3,2,2,1,2,1,

6,1,1, 5,2,1, 3,2,1, 2,2,4,2,2,3, 3,2,1,5,2,2,

5,2,1, 6,2,1, 3,2,2, 2,2,2,1,2,4, 5,2,3,3,2,1,

2,2,1, 1,2,1, 6,1,1, 1,2,1,5,1,6, 0,0,0

}

// 音阶烂亩频率表 定时器高八位

code unsigned char FREQH[]={

0xF2,0xF3,0xF5,0xF5,0xF6,0xF7,0xF8,

0xF9,0xF9,0xFA,0xFA,0xFB,0xFB,0xFC,0xFC, //1,2,3,4,5,6,7,8,i

0xFC,0xFD,0xFD,0xFD,0xFD,0xFE,

0xFE,0xFE,0xFE,0xFE,0xFE,0xFE,0xFF,

}

// 音阶频率表 定时器低八位

code unsigned char FREQL[]={

0x42,0xC1,0x17,0xB6,0xD0,0xD1,0xB6,

0x21,0xE1,0x8C,0xD8,0x68,0xE9,0x5B,0x8F, //1,2,3,4,5,6,7,8,i

0xEE,0x44, 0x6B,0xB4,0xF4,0x2D,

0x47,0x77,0xA2,0xB6,0xDA,0xFA,0x16,

}

/*------------------------------------------------

uS延时函数，含有输入参数 unsigned char t，无返回值

unsigned char 是定义无符号字符变量，其值的范围是

0~255 这里使用晶振12M，精确延时请使用汇编,大致延时

长度如下 T=tx2+5 uS

------------------------------------------------*/

void DelayUs2x(unsigned char t)

{

while(--t)

}

/*------------------------------------------------

mS延时函数，含有输入参数 unsigned char t，无返回值

unsigned char 是定义无符号字符变量，其值的范围是

0~255 这里使用晶振12M，精确延时请使用汇编

------------------------------------------------*/

void DelayMs(unsigned char t)

{

while(t--)

{

//大致延时1mS

DelayUs2x(245)

DelayUs2x(245)

}

}

/*------------------------------------------------

节拍延时函数

各调1/4节拍时间：

调4/4 125ms

调2/4 250ms

调3/4 187ms

------------------------------------------------*/

void delay(unsigned char t)

{

unsigned char i

for(i=0i<ti++)

DelayMs(250)

TR0=0

}

/*------------------------------------------------

定时器0中断

------------------------------------------------*/

void TIM0_ISR() interrupt 1

{

TR0=0

SPK=!SPK

TH0=Timer0_H

TL0=Timer0_L

TR0=1

}

/*------------------------------------------------

歌曲处理函数

------------------------------------------------*/

void Song()

{

TH0=Timer0_H//赋值定时器时间，决定频率

TL0=Timer0_L

TR0=1 //打开定时器

delay(Time)//延时所需要的节拍

}

/*------------------------------------------------

主函数

------------------------------------------------*/

void main(void)

{

unsigned char k,i

TMOD|=0x01//置定时器0工作方式1

EA=1 //打开全局中断

ET0=1 //打开定时0中断

while(1)

{

i=0

while(i<100)

{ //音乐数组长度 ，唱完从头再来

k=MUSIC[i]+7*MUSIC[i+1]-1//去音符振荡频率所需数据

Timer0_H=FREQH[k]

Timer0_L=FREQL[k]

Time=MUSIC[i+2] //节拍时长

i=i+3

Song()

}

}

}

#include <瞎含reg51.h> //头文件

unsigned char count//定义全局变量，是一个计数器，0-255计数，仔神档用来计时一个频率的时长

sbit speak=P2^3 //蜂念乱鸣器口

unsigned char code song[]={ //歌曲代码，存储方式为：频率，时长，频率，时长...

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,

0x30,0x1C,0x10,0x20,0x40,0x1C,0x10,0x18,0x10,0x20,0x10,0x1C,0x10,0x18,0x40,0x1C,

0x20,0x20,0x20,0x1C,0x20,0x18,0x20,0x20,0x80,0xFF,0x20,0x30,0x1C,0x10,0x18,0x20,

0x15,0x20,0x1C,0x20,0x20,0x20,0x26,0x40,0x20,0x20,0x2B,0x20,0x26,0x20,0x20,0x20,

0x30,0x80,0xFF,0x20,0x20,0x1C,0x10,0x18,0x10,0x20,0x20,0x26,0x20,0x2B,0x20,0x30,

0x20,0x2B,0x40,0x20,0x20,0x1C,0x10,0x18,0x10,0x20,0x20,0x26,0x20,0x2B,0x20,0x30,

0x20,0x2B,0x40,0x20,0x30,0x1C,0x10,0x18,0x20,0x15,0x20,0x1C,0x20,0x20,0x20,0x26,

0x40,0x20,0x20,0x2B,0x20,0x26,0x20,0x20,0x20,0x30,0x80,0x20,0x30,0x1C,0x10,0x20,

0x10,0x1C,0x10,0x20,0x20,0x26,0x20,0x2B,0x20,0x30,0x20,0x2B,0x40,0x20,0x15,0x1F,

0x05,0x20,0x10,0x1C,0x10,0x20,0x20,0x26,0x20,0x2B,0x20,0x30,0x20,0x2B,0x40,0x20,

0x30,0x1C,0x10,0x18,0x20,0x15,0x20,0x1C,0x20,0x20,0x20,0x26,0x40,0x20,0x20,0x2B,

0x20,0x26,0x20,0x20,0x20,0x30,0x30,0x20,0x30,0x1C,0x10,0x18,0x40,0x1C,0x20,0x20,

0x20,0x26,0x40,0x13,0x60,0x18,0x20,0x15,0x40,0x13,0x40,0x18,0x80,0x00,

}

void time0_init() //定时器初始化函数

{

TMOD=0x01//工作方式，16位定时器

IE=0x82 //允许定时器T0中断和总中断

TH0=0xDC //定时器初值高8位，具体时间需要根据晶振计算

TL0=0x00 //定时器初值低8位

}

void time1_int() interrupt 1 //定时器中断函数

{

TH0=0xDC //定时器重赋初值高8位

TL0=0x00 //定时器重赋初值低8位

count++ //计数器自加

}

void delay_xms(unsigned int x) //延时函数

{

unsigned int i,j//定义延时函数局部变量

for(i=0i<xi++)//用for循环实现延时

for(j=0j<3j++) //数值很小，不应该是ms级的，此函数用来改变蜂鸣器频率

}

void play_song(unsigned char i) //歌曲播放函数

{

unsigned char temp1,temp2 //定义局部变量，temp1为频率缓存器，temp2为时长缓存器

unsigned int addr //定义局部变量，是一个数据地址缓存器

count=0 //计数器清零

addr=i*217 //两首歌，数组中0~216为歌曲0，

while(1) //此循环

{

temp1=song[addr++] //从0开始，取偶数地址中的值（频率）放到缓存器temp1，addr自加

if(temp1==0xff) //如果遇到0xff

{

TR0=0 //不允许定时器T0计时

delay_xms(100) //延时，此处0xff可能是停顿符号

}

else if(temp1==0x00) //否则如果遇到0x00

{

return //函数返回，此处的0x00应该是歌曲播完的符号

}

else//否则

{

temp2=song[addr++] //取奇数地址中的值放到缓存器temp2，addr自加

TR0=1 //允许定时器T0计时

while(1) //此循环用来调节蜂鸣器发声频率和时长

{

speak=~speak//蜂鸣器取反，此蜂鸣器为它激式，可以用改变取反频率方式实现发出不同音调

delay_xms(temp1) //延时相应频率所需时长

if(temp2==count)//如果相应频率发声时长与计数器数值相同

{

count=0//计数器清零

break//跳出该while循环

}

}

}

}

}

void main() //主函数

{

time0_init() //调用定时器初始化函数

while(1) //单片机进入正常工作死循环

{

play_song(0) //调用播放歌曲函数，并且播放歌曲0

}

}

/*****

/*我的注释中其实有个错误：取偶数地址中的值放到temp1，取奇数地址中的值放到temp2。因为有0xff停顿符号和0x00停止符号存在于歌曲代码中，以至于偶数地址中并非全是频率代码、奇数地址中并非全是时长代码。但我这样写是方便你理解，所以最后作此说明。*/

*****/

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