51单片机.之蜂鸣器振动播放歌曲

蜂鸣器发声是通过喇叭振动发声的，通电产生磁场，磁铁吸收，而振动。不断释放，吸收。

1、蜂鸣器发声，播放不同频率的声音逐渐变尖

c 复制代码

#include<reg52.h>

sbit BUZZ = P1^6;

unsigned char T0RH=0;
unsigned char T0RL=0;
void OpenBuzz(unsigned int frequ);
void StopBuzz();

void main()
{
	unsigned int i;

	EA =1;
	TMOD = 0x01;

	while(1)
	{
		OpenBuzz(4000);
		for(i=0; i<40000; i++);
		StopBuzz();
		for(i=0; i<40000; i++);
		OpenBuzz(1000);
		for(i=0; i<40000; i++);
		StopBuzz();
		for(i=0; i<40000; i++);

	}
}

void OpenBuzz(unsigned int frequ)
{
	unsigned int reload;

	reload = 65536 - (11059200/12)/(frequ*2); 
	T0RH = (unsigned char)(reload >>8);
	T0RL = (unsigned char)reload;

	TH0 = 0xFF;
	TL0 = 0xFE;

	ET0 = 1;
	TR0 = 1;
}

void StopBuzz()
{
	ET0 = 0;
	TR0 = 0;
}

void InterruptTimer0() interrupt 1
{
	TH0 = T0RH;
	TL0 = T0RL;
	BUZZ = ~BUZZ;
}

2、蜂鸣器播放歌曲

c 复制代码

#include <reg52.h>

sbit BUZZ = P1^6;  //蜂鸣器控制引脚

unsigned int code NoteFrequ[] = {  //中音1-7和高音1-7对应频率列表
    523,  587,  659,  698,  784,  880,  988,  //中音1-7
    1047, 1175, 1319, 1397, 1568, 1760, 1976  //高音1-7
};
unsigned int code NoteReload[] = { //中音1-7和高音1-7对应的定时器重载值
    65536 - (11059200/12) / (523*2),  //中音1
    65536 - (11059200/12) / (587*2),  //2
    65536 - (11059200/12) / (659*2),  //3
    65536 - (11059200/12) / (698*2),  //4
    65536 - (11059200/12) / (784*2),  //5
    65536 - (11059200/12) / (880*2),  //6
    65536 - (11059200/12) / (988*2),  //7
    65536 - (11059200/12) / (1047*2), //高音1
    65536 - (11059200/12) / (1175*2), //2
    65536 - (11059200/12) / (1319*2), //3
    65536 - (11059200/12) / (1397*2), //4
    65536 - (11059200/12) / (1568*2), //5
    65536 - (11059200/12) / (1760*2), //6
    65536 - (11059200/12) / (1976*2), //7
};
bit enable = 1;   //蜂鸣器发声使能标志
bit tmrflag = 0;  //定时器中断完成标志
unsigned char T0RH = 0xFF;  //T0重载值的高字节
unsigned char T0RL = 0x00;  //T0重载值的低字节

void PlayTwoTiger();

void main()
{
    unsigned int i;
    
    EA = 1;       //使能全局中断
    TMOD = 0x01;  //配置T0工作在模式1
    TH0 = T0RH;
    TL0 = T0RL;
    ET0 = 1;      //使能T0中断
    TR0 = 1;      //启动T0
    
    while (1)
    {
        PlayTwoTiger();  //播放乐曲--两支老虎
        for (i=0; i<40000; i++);  //停止一段时间
    }
}
/* 两只老虎乐曲播放函数 */
void PlayTwoTiger()
{
    unsigned char beat;   //当前节拍索引
    unsigned char note;   //当前节拍对应的音符
    unsigned int time = 0;      //当前节拍计时
    unsigned int beatTime = 0;  //当前节拍总时间
    unsigned int soundTime = 0; //当前节拍需发声时间
    //两只老虎音符表
    unsigned char code TwoTigerNote[] = {
        1,   2,   3, 1,    1,   2,   3, 1,   3, 4, 5,   3, 4, 5,
        5,6, 5,4, 3, 1,    5,6, 5,4, 3, 1,   1, 5, 1,   1, 5, 1,
    };
    //两只老虎节拍表，4表示一拍，1就是1/4拍，8就是2拍
    unsigned char code TwoTigerBeat[] = {
        4,   4,   4, 4,    4,   4,   4, 4,   4, 4, 8,   4, 4, 8,
        3,1, 3,1, 4, 4,    3,1, 3,1, 4, 4,   4, 4, 8,   4, 4, 8,
    };
    
    for (beat=0; beat<sizeof(TwoTigerNote); )  //用节拍索引作为循环变量
    {
        while (!tmrflag);  //每次定时器中断完成后，检测并处理节拍
        tmrflag = 0;
        if (time == 0)  //当前节拍播完则启动一个新节拍
        {
            note = TwoTigerNote[beat] - 1;
            T0RH = NoteReload[note] >> 8;
            T0RL = NoteReload[note];
            //计算节拍总时间，右移2位相当于除4，移位代替除法可以加快执行速度
            beatTime = (TwoTigerBeat[beat] * NoteFrequ[note]) >> 2;
            //计算发声时间，为总时间的0.75，移位原理同上
            soundTime = beatTime - (beatTime >> 2);
            enable = 1;  //指示蜂鸣器开始发声
            time++;
        }
        else  //当前节拍未播完则处理当前节拍
        {
            if (time >= beatTime)  //当前持续时间到达节拍总时间时归零，
            {                      //并递增节拍索引，以准备启动新节拍
                time = 0;
                beat++;
            }
            else  //当前持续时间未达到总时间时，
            {
                time++;   //累加时间计数
                if (time == soundTime)  //到达发声时间后，指示关闭蜂鸣器，
                {                       //插入0.25*总时间的静音间隔，
                    enable = 0;         //用以区分连续的两个节拍
                }
            }
        }
    }
}
/* T0中断服务函数，用于控制蜂鸣器发声 */
void InterruptTimer0() interrupt 1
{
    TH0 = T0RH;   //重新加载重载值
    TL0 = T0RL;
    tmrflag = 1;
    if (enable)   //使能时反转蜂鸣器控制电平
        BUZZ = ~BUZZ;
    else          //未使能时关闭蜂鸣器
        BUZZ = 1;
}